Trigger GREEN Traffic Lights

if you or someone you know, owns a motorcycle, a scooter or even a small car, you've probably noticed that it's easy to get stuck at traffic lights. Well, I'm going to explain why it happens and show you a great little trick that will save time, gas and frustration by getting you a green light every time.

Step 1: The Problem...

At most traffic lights and turn signals, you will notice a loop of wire buried in the pavement of the road near the stop line. This is called an Inductive-loop traffic detector that operates by sensing a change in frequency to the electromagnetic field over the coil of wire. In other words, when a car pulls up, it senses the vehicle and the light changes. Most motorcycles, scooters, bicycles and small cars don't have enough conductive material to trigger these loops and change the traffic light.

Comments

[cathys]

First thing...if you have a scooter you should ride on the side of the road with bicycles instead of putt putting along where people in cars, trucks and motorcycles travel. Second thing...if you took a motorcycle course or did some research you would find out that the lines underground can sense metal. So, if you are on a little scooter or even a motorcycle there is not enough metal for it it sense that's why you will see a motorcycle at a line moving their bike back and forth over the line and Third thing....really? really? You can't wait one minute for a light? dah

[snuzzle]

First, yes a bicycle or slow scooter should be on the side of the road... unless there is a right-turn lane, in which case he or she should be in the through lane so as not to get right-hooked by a car making a right turn :) I'm not going to get right-hooked. If I'm going straight, I'm in the through lane. If I'm turning left, I'm biking to the left. You know? Common sense here.

Thirdly, it's not a matter of waiting... some lights do not change at all unless they detect a vehicle. The magnets allow them to detect that a bike or small scooter is there so they know they need to change.

[Furball_Fidelis]

Yes..scooters are entitled to ride on the road just like any other road legal motorized vehicle...and most of them are able to keep up with traffic however scooters are not meant for highways where the speed limit is 65Mph or 100Kmph (not 100% on the conversion) and yes...I own a motorcycle and it's only a small one a 250 Suzuki..and at most intersections i'm able to trigger the light...but there's very rare times when I have to move my bike around to trigger them

[cowen]

One of my customers has a 80 model Harley and had the magnet idea professionally installed some years ago because of the loops not picking up very well. The loops are burried in cement so the only way to FIX them is to dig up the payvement. The only way to check them for PROPER operation is to trigger them. If the cement shifts in the heat and cold that can break the loop and thus you need something to help trigger them. The Loop starts most lights counters that change them to green it is not a Green light EMS device that makes your side change and everyone else RED. I work on LOOPS at the drive thru and sometimes we have to cut them out and replace them or fix the junctions that connect to the inside equipment.

[anjin12]

Cathys --- First things first. Scooters ARE entitled to be on the road, they are a "motorized" vehicle, and, as such, shall NOT travel in the bicycle lane if marked. Second, most states and provinces require that "bicycles" travel "As far to the right as practicable", not as far as possible and recommend that a path 1 metre or 3 feet be maintained from the edge of the road. .... Now ... for the rest of your comment ... Most bicycles have enough ferrous material in the crank set (pedals) to activate the sensors embedded in the road. The bicycle must be on the outside edge of the circle to "change" the current to activate the lights. For more information see ... http://www.humantransport.org/bicycledriving/library/signals/detection.htm ... Thanks and have a good day

[cathys]

putt putt

[snuzzle]

Waiting at a red light with your bike laying on the pavement isn't really safe, so it's not really feasible. As soon as you move off the conductor (ie, stand your bike up) the light assumes you've moved on and that it doesn't have to change.

I haven't tried the magnets yet, but I'm going to. You can also try aligning your wheel and frame with the outline of the detector. This allows for the most metal in direct line with the conductor and should (usually) get you a light change.

[dscotthep]

Any metal will disturb the field of an inductor (metal detectors are nothing more than inductors-on-a-stick!) A powerful magnet just gives you more bang for your buck.

[pcooper2]

As an ultimate test, I took a powerful rare-earth magnet salvaged from an old hard disk drive and taped it to the end of a 10-ft long PVC pipe, then waved it over the sensing loop at a quiet intersection where cars only passed every few minutes. The light only changed when cars arrived at the intersection, but never did while I was just waving the magnet. Conclusion: It doesn't work. Don't waste your time or money.

[Ludwig Von Mech]

I had a rather large and powerful magnet, and I attached it to my bottom bracket. I thought it was working, but after about 4 months of testing, I conclude that magnets do not work. Wait for a break in the traffic and just go.

[Ludwig Von Mech]

In Wisconsin this is no longer a problem, as in 2010 we got a new law that allows bikes to wait and proceed through the red if traffic allows. I used to report all the lights that did not work, but now I don't bother. I just ride through.

[pcooper2]

I've been treating signals with unresponsive road sensors as four-way stops for decades, even without the benefit of such a law. If I hadn't, I'd have died of thirst and starvation while waiting for the light to change ages ago!

[2 stroke]

awesome i let a car get in front of me lol

[NatureGeek24]

We have that here, too. But sadly, it doesn't apply much for heavy traffic when you have a line of cars behind you getting madder with each missed cycle and no opening to go. This is a helpful fix.

[Ludwig Von Mech]

You have a very good point.

Another way to fix this situation is to become proactive; the inductive coils in the road will not trigger if they are out of adjustment. I have reported these for years and years, and I have also seen them become so bad that a pickup truck will not work. The state supervisor is on my email list, and he will send out a crew if someone complains. They do not have time or manpower to continually inspect each light.
I will try this magnetic solution at a place that I know does not work.

Also, if you are on a bicycle or moped, do not hug the curb. You will get old waiting for the change. Ride over the lines slowly, and position yourself directly on top of the transverse wire. If it is still working, you will trip it.

Happy riding.

[dylanl]

Cool

[boom1234]

find the I !!!! TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTITTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT

[crazyg]

cool, so i guess revving the nuts of your motor at the lights does the magneticy thing thus changing light,

[cyber_meat]

you can also do it a different way using a universal remote.

[Spense09]

yeah. but I bet thats illegal what your saying. would you have to hack the traffic light for a remote for it to work with a control

[cyber_meat]

first of all no it's not illegal, second the cops can't arrest you for having a universal remote on your dashboard, and third their is no law against doing it. no there is no traffic light hacking needed for it to work; you just need the sensor code. i am not saying the code because it is so obvious if you can't figure it out then oh well i don't really care.

[brhoney]

which button on the Uni remote do you use to change the light?

[brhoney]

911 maybe?

[mikerosati]

Everything you said proves you do not know what you're talking about.. Here are the actual facts, from someone who works on those systems: 1. It is illegal for non-emergency vehicles to trigger (and attempt to trigger) the emergency pass system. If you think a universal remote magically has the "codes" you speak of, everyone would be trying it. (see next note) 2. The "code" you speak of is a simple 14hz flash from a high-powered infrared strobe mounted on the dash or exterior of an emergency vehicle. Universal remotes use a morse-code like flash pattern, which these signals ignore. 3. Bringing back to point one, yes, you can be arrested if an officer sees you just trying to trigger that sensor. You obviously don't know that the basic circuit being sold to most localities also records data about each trigger, including the time it occurred - fairly easy to prove you were the one who tried to trigger it, when they can figure out when you went through the intersection. 4. While ignorance may be bliss, you arrogance doesn't help anyone, including yourself. Please read up before you try to push someone down with complete misinformation.. Next time learn from an actual source, and contribute to the conversation - People will give you respect when you give it.. Thank you.

[acassis1]

Thank You Mike Rosati, it's about time people start telling things as they really are, you'd be surprised who pushes to wrong excesses, check on Facebook PM's fall from grace... it's too bad that such a useful info-mag. slips in so lightly, dangerous lies & wrong infos. But thanks for putting things to wright.

[chrwei]

most tv/dvd/stereo remote IR operates at 38Khz anyway. maybe programming it to turn off an on at 14Hz would work, but it's still illegal.

[cjrush1009]

No Cyber, it is COMPLETELY illegal to have a remote device the changes lights. We had a guy here who was doing it but what the guy didnt know is that every time the lights get tripped by an IR signal they log the event and the DOT audits the reports. So the DOT noticed that around 8am a whole line of lights start getting tripped everyday during the week. They checked the cameras at the intersection and noticed the same red truck going through. They got the license plate number and put cops at the intersection. When they guy came through and tripped the lights they pulled the guy over: they found his hacked remote and busted him; he's in jail. Dont think for a minute that you would get away with something like that because you wont. They have already considered the possibility and they have a system to catch people who do that.

[pcooper2]

References, please. Without any references, what you write is an interesting anecdote or urban legend, nothing more.

[clintsmithgsm]

what makes you think your special. those devices are so i can get to your dying grandma not to get to class or the nearest burger joint........your so cool! i hope you get caught you don't care about the rules of the road? driving is a priviledge you don't deserve hopefully you don't get caught bye creaming someone or me

[RainyDayInterns]

It's "you're so cool...", not "your so cool." Thought we would mention it as you seem to care about proper spelling, so we assumed you cared about proper grammar as well.

[cornonthecobert]

So? I'm like that too but typos happen. You've probably done it many times yourself.

[cyber_meat]

dumass look at the post date

[kinetic_elite]

Where's the "b" eef?

[clintsmithgsm]

first of all learn to spell and that doesn't change anything

[janettetsmith]

You probably want to make sure you spell everything correctly before blazing the all-knowing grammar-spelling-comment.  Case in point: ... get caught bye creaming someone or me (needs punctuation at the end of the sentence, as well).

[kinetic_elite]

Thank-you

[kinetic_elite]

This is proof that all those English majors should have just become armchair engineers, instead. So they can spend all their time flaming comment boxes instead of collaborating together to make these ideas into valid inventions. Just save me the highschool drama performence of "I feel so bad for myself" . Oh no! Now I have now potentially set myself up to get banned. It would be worth it just to change my name and IP address and come back to criticize all of your posts!

[Dubi01]

If you live in the United States and try to use any kind of triggering device, it is and always has been illegal. I work for the local dept. of transportation installing and repairing signalized traffic systems and all these home gizmos don't work.

[kinetic_elite]

Thank you for the information! Much appreciated to hear this from someone who knows what they are talking about!

[thenameisbam]

Well i know in california it is illegal, and can carry heavy fines if you do it and are caught, even more so if you do it and there is an accident.

[Spense09]

word. PIIEEEE!!!!

[Spense09]

ok i dont know the code and its not obvious for idiots like me. could you tell me

[gsdkain]

I'm guessing 911 or 1234 or something like that.

[whyexactly]

the codes are a bit different from that.

[robocrazy155]

Is it "password"? Or "Password"? Or "Password1"? Something along those lines?

[chrwei]

did you try GOD?

[whyexactly]

that's not at all how a universal remote is set. If he's talking about a garage door remote it's all 1's and 0's, a TV remote is usually a series of numbers (usually depends on the remote) but the range isn't going to be near long enough to trigger anything, even if you did find the right code and happen to have the right frequencies.

[cwtstraydog]

it is "IDKFA"

[tvanzyl]

Whahaha! Best comment ever!

[rmelchiori]

I think that the idea the author is talking about has been misunderstood. The problem isn't trying to get a red light to turn green so he doesn't have to wait. Many intersections have sensors at them so that the light never changes unless it senses a vehicle. This is done to promote better traffic flow. Same thing for left turn lanes. I know that this technique works. There is actually a product sold to do this. Nothing more than a magnet mounted under the motorcycle. Not even a rare earth magnet. I bought one for my motorcycle and it worked well.

[lucek]

Except you aren't doing it in a blinded fashion. Review the evidence: !:Prior probability, low as this is based off a misconception on how the censors work. 2:All test that confirm the effectiveness aren't well controlled and can be just the rain-maker fallacy. 3:One test show the lack of effect. Thees 3 factors would suggest that it doesn't work.

[Lee Wilkerson]

These triggers work on the same principal as passive theft detection in stores: An oscillator is running with a very large coil. In the case of the car sensor, the coil is under the road. When something with enough metal bulk is over the sensor, it shunts the coil and changes the frequency of the oscillator.
It is the same principal as:
http://hackaday.com/2008/08/10/free-parking-garage-access/
All you need is for the magnet to be in close proximity to the sensor.
In the photos, the trigger type is a narrow loop. Those usually sense motorcycles anyway. It's the wide loop ones which don't. Almost none of them will sense a bicycle, so if you can make a bicycle trigger one, then you've got it.

[lucek]

The test I would propose it to have a wooden object at a objectively verifiable trigger (there was an example were the coil operated a gate) and install a magnet on it. Isolate the variables.

[JMRaphael]

If I understand the video correctly, the author is demonstrating at a light that will change if and only if the sensor is triggered. If the magnet didn't work, then the light wouldn't change at all. That, effectively, is your blind. The control situation is what he shows first: a motorcyclist at the light that will not change for him. The experimental situation is the motorcyclist at the light with the magnet attached. Since the light changes, the magnet must work.
From a theoretical perspective as well, this should work. If you look at an inductor, a simple metal core (what you get with a steel-frame car) changes the inductance a little bit. Since most bikes, scooters, etc lack sufficient metal to significantly change the inductance, magnets are added. This works because magnets have a much greater effect, based on the strength of the field they create. Such strong magnets alter the inductance sufficiently to trigger the sensor.

[lucek]

"If the magnet didn't work, then the light wouldn't change at all."

That's the error. The lights will change eventual and the question if the vehicle it's self can cause the effect has been show. Further we only have the word of the video maker that the light doesn't change on a timer or the like. We have no sign that he has the plans at his disposal or anything to verify it.

"This works because magnets have a much greater effect, based on the strength of the field they create."

Not true. Inductance isn't effected by magnetic fields but by the composition of the metal. for instance copper has higher inductance then neodymium magnets. Copper is diamagnetic and neodymium iron boron is one of the strongest magnets we know.

[jack8559]

Okay then lucek, can we count on you to fit everyone's scooters and/or bicycles with 'God only knows' how much copper? What size is this copper and how long is it, or is it in several pieces arranged in what manner? How about at least making an 'ible telling people exactly how much copper to use and exactly how to configure the copper for small vehicles? It's always better to show your results than to rant about it.

If you can give the proper way in your opinion to all the readers on here I'm sure that people would look at it and some would try it and comment whether it works for them. I think a good source of information on this would be your town's or state's department of highways or whoever puts these sensors in the roadways.

There are lights that do change every so often without the coils being triggered where I live, but I really don't like waiting for 2 hours(or more) at the light for it to happen. Since it's legal to turn right on red in my state after stopping, I usually have to turn right then make a U-turn which in my opinion is NOT the safest thing to do a lot of times.

[lucek]

If you don't mind I was pointing out poor methodology and shady science. That was 8 months ago. I really don't care about this anymore. I've stated my peace and frankly this bump is practically a troll.

[abadfart]

not necessarily there is a light by my apartment that wont change if there is not a car at it aster midnight. my bike is big enough to trigger it but my sisters isn't

[JMRaphael]

In this situation, however, the lights will not change eventually. Some intersections have lights that must be triggered for change to occur. Green arrows operate on the same principle; the green arrow won't be activated unless the sensor is triggered. I agree that there is a risk for the confirmation bias if the light would change eventually, but (as I understand it) this was tested successfully on a light that had to be triggered to change.

Inductance is, in fact, affected by magnetic fields. I have worked with inductors in a laboratory setting; inserting an iron core will produce a moderate change in the inductance while inserting a magnet will produce a large change. This is because inductance is proportional to the EMF through the coil, which is in turn proportional to the magnetic flux. Cars are detected because the metal in the car is affected by the inductor and in turn affects the inductor. A magnet is detected because it directly changes the magnetic flux.

Source: http://micro.magnet.fsu.edu/electromag/electricity/inductance.html

[lucek]

I'm not going to argue with you as well but you have not countered my points.

"In this situation, however, the lights will not change eventually."

That information isn't known. It is claimed and it may well be believed by the author but we see no proof.

"Inductance is, in fact, affected by magnetic fields."

Inductance is a effect of metal moving in a magnetic field. The mane property that increases or decreases inductance is electrical resistance. I must say for someone who works with it you seem to have a major misconception of how it works. Claiming that magnetism on the receiving end is important when it is only so on the origin end.

[JMRaphael]

There's no reason to expect the author to be wrong in this event, particularly since the author has a history of building successful and scientifically sound projects. In addition there are a number of similar projects on Instructables and other sites, as well as similar products for sale. The probability of this device being unsuccessful but still touted by so many is so statistically improbable that one must assume that this project has some effect.

Furthermore, the physics of the project is sound. Inductance is not an effect of metal moving in a magnetic field. In the basic sense, inductance is a property of a coil of wire with a current running through it. The current creates a magnetic field that is normal to the direction of the current. With a coil of wire, the magnetic field that the current induces ends up being "directed," forming closed field loops perpendicular to the direction that the wire coils.
The inductance seen here does not require any core. It is based on the magnetic flux through the coil (which is generated by the current, known as self-inductance), the number of turns in the coil, and the voltage.
Introducing a core changes the inductance (different cores will affect the self-induced magnetic field), but it is not creating the inductance. Introducing a magnet will result in a change in the magnetic flux through the coil, having a profound effect on the inductance.
tl;dr: a wire loop with a current is an inductor, different cores will change inductance but do not create inductance, and magnets will have a stronger effect than non-magnetized cores. If you don't believe me, look it up.

[lucek]

"The probability of this device being unsuccessful but still touted by so many is so statistically improbable that one must assume that this project has some effect."
By that logic HHO engines work. The fact is we have every reason to doubt him.

"Introducing a magnet will result in a change in the magnetic flux through the coil, having a profound effect on the inductance.
tl;dr: a wire loop with a current is an inductor, different cores will change inductance but do not create inductance, and magnets will have a stronger effect than non-magnetized cores."

I have looked it up (and remember it from back in my college days). the resistance to magnetic flow is a big factors in the inductance, but not as much as electrical resistance of the material.

[rmelchiori]

Dude, Check this site out. This is only one that I found that are selling this. I actually used it and can tell you it works. If you don't want to believe it, that's up to you. http://www.greenlightstuff.com/trigger.html

[finton]

That link just gets a "404 (Page Not Found) Error" now...

[rmelchiori]

Do a Google search for 'motorcycle green light trigger' and you'll find a bunch of different types. There is also a bunch on Amazon.com.

[lucek]

I just explained how you are most likely mistaken and you counter my argument by sending me to a site that has a major bias to claiming it works (IE they're selling it). Do you see the problem here? Restating the points, the magnetic field is too weak to effect the censor in any major way. The censers measure inductance not magnetic fields so non-ferromagnetic metallic materials will trip the censer. The only proof you've cited is anecdotal in nature and can fall under confirmation bias AKA the rainmaker fallacy. Finally bguiles recounts an experiment that negates the premise of thees devices. What are we left to think? The most likely conclusion is that thees don't work.

[Wesfletch]

He literally said, HE used it and it worked. It doesnt matter if the site has a bias, he doesnt. And, why does it even matter, you're here, complaining about someone ELSES work, saying its B.S. But, have you tested it? Theory is all well and good, but hard fact is necessary to even attempt a semi-accurate educated guess. I think, before you try to disprove someones hard work, you actually have the decency to take the time to back it up.

[lucek]

look up the rainmaker fallacy would you.

[janettetsmith]

@lucek: It sounds as like you are calling @rmelchiori a liar. Hmm. Well then, if you can do that you are without a doubt an expert on this topic.

[lucek]

No I specifically stated I didn't think he was a liar. The rain maker fallacy is a kind of self deception. it is very easy to trick oneself and the nature of this case appears to be such. Now I'm not an expert on the topic but what knowledge I have from my 200 level courses I've taken, research and reading from others says that this is wrong. Finally before accusing someone of slander check to see if you are in fact mistaken.

[janettetsmith]

@lucek: Slander is verbal, you probably meant libel, that’s the one where you write it.

[lucek]

Pedantic is both.

[janettetsmith]

@lucek: Your attempt to turn the attention on someone that pointed out your mistake by referring to them as nit picky is predictable. However, now you are up to two words used incorrectly. Anyone that can read can see you used the wrong word. They don’t have to be on the head of a pin to do it. You’re a bully. I’ll bet you love the Internet.

[lucek]

Um. pot, kettle, black much? Do you have a point beyond trolling?

[randomray]

Apparently you don't ride a bike , as many cyclists know they can tape a magnet to the bottom bracket of thier bicycle so the coils in the road will pick them up . Yes , this does work whatever the reason .Empirical data trumps theory every time . And lucek why are you trolling ?

[kinetic_elite]

Give this guy a break. Maybe he doesn't spend all day thinking about sensors! Why start a flame war?

[Emsaid]

hmmm dont know whether this works or not... im just going to try it!

[CrazyHowiesBikes]

I have a few points to make. First off, Kipkay, thank you!!! I can now take the shorter route to my destinations, instead of my current one that was based on little or no traffic lights.

Secondly, this DOES work for the induction type signals. Last week I installed 2 hard drive magnets on my bicycle, one under the crank housing, and one near the kickstand mounting plate. My bike is a Raleigh M30 XL and is all steel. I have a homemade cargo trailer that is also steel. For some reason unbeknownst to me, most lights ignore my existence. NOT ANY MORE!!! I have tried this at every intersection in my small town. Some advice: if you live in an area that uses timers, all you can do is be patient. If you live in an area that uses motion detectors, I don't know, try jumping up and down while flapping your arms. This might not work, but at least you'll be doing something instead of just sitting.

Finally, I must say, as a part-time insomniac, I spend those sleepless nights trying to educate myself by perusing the internet, searching out topics that interest me. I've read a lot of comments left on people's blogs, instructables, etc. I have to say that many, not all, but many of the people who left their opinion on this i'ble need to just do us all a favor and sell their computers. People who leave negative comments just to start sh*t (trolls) defeat the purpose of this website and bring the community down. Like my grandma told me, "If you can't say something nice about 'em, don't say anything." Based on that, I have nothing more to say!

Thanks again Kipkay! YOU ROCK!!!

[BEAST14]

Is this legal? And would it work on a full sized truck?

[Lee Wilkerson]

You don't need one on a full-sized anything.

[Steve66oh]

How is it that the chrome-plated pill holder doesn't act like a Farraday Cage - enclosing the magnetic field and insulating it from the traffic sensor?

[Ben5504]

Faraday Cages only screen out electric fields, not magnetic ones.

[Lee Wilkerson]

That case will certainly attenuate the magnetic field.

~/Lee

[Starleaf]

It seems like the tape wouldn't be strong enough under those conditions.

[Exocetid]

When I saw the email note on this my first thought was that you were showing people how to do the highly illegal and life threatening way to activate opticon sensors at intersections; i.e., those used by first responders to activate light changes. Imagine my relief when I saw your excellently clever solution to a problem that often plagues the owners of small vehicles!

[Spokehedz]

This also helps out on bicycles where communities have laws against them riding on the sidewalk. Only problem is that you need REALLY REALLY strong magnets because the bikes are so much higher off the ground. I solved this by putting the magnets in my shoes, so that I can really put my foot down and change the light. But they pick up metal from time to time like screws and nails... Not so good.

[kinetic_elite]

Do you recycle the nuts and such into other projects at home later? Just sayin'

[Spokehedz]

Most of the time the stuff is rusty beyond use. I would if I could... mostly it goes onto the recycle bin.

[IG-88]

Imagine my disappointment when I realized that this WASN'T a way to activate opticon sensors. Being a delivery vendor in our city I can only imagine how much time I could save by having one of those. Thanks Exocetid for that great idea!

[joshcube]

Go for it... but just know that if you're in the US, using such a device is considered an act of terrorism. And it would be very easy for them to catch you since intersections with traffic cameras can see the IR signal. We're not talking a fine and a ding on your DMV record, you would be facing time in federal prison.

[sires6]

Terrorism? Really? It's an act of terrorism to do a lot of things. But putting a magnet on the bottom of your vehicle so that it trips a sensor that is designed to do just the thing you are trying to get it to do is called common sense, not terrorism. I'd go to Federal Court for that one! And what is the camera going to see? A guy stopping on a moped at the light and then... oh my, the light changes and he goes? Stop HIM!!! TERORRIST!!! Sorry, I am not a paranoid and have little patience for them. Hope I didn't offend or at least I hope you realize I am not trying to offend, merely point out the error of your logic. Oh, and I am a former police officer. I would arrest for many things, but this? No.

[joshcube]

My comment was about the use of an opticon device which is a federal crime under the Safe Intersections Act. Such devices are infrared and traffic light cameras can display the infrared spectrum. Disrupting traffic can also be considered an act of terrorism, but the last time someone was brought up on terrorism charges for disrupting traffic during a demonstration it was thrown out by the judge. Regardless it's still a federal crime to use an opticon device unless you're in an emergency service vehicle. As for the magnet device.... perfectly legal, but it seems unnecessary. In college I saw people use a small cookie sheet to keep a ground loop gate sensor open so their friends could get on campus without buying a parking pass. It doesn't take much metal at all to activate them.

[sires6]

Unfortunately it was not obvious that your comment was about the opticon and not about the piece of metal itself. My apologies for my ranker and hope it cause no ill will or feelings.

[IG-88]

Terrorism? BS. Prove that.

[Exocetid]

I could instruct you on how to do it, but I would not want to be party to the lawsuit that would result if you caused a major accident using it. Remember, it's illegal as well.

[cowen]

Only one green light is given when the opticon is activated. Ask the Fire truck driver that ran a red light thinking he was going to get a green light, when the responding Fire Truck got the green light first and enter the intersection at the same time the 2ndary truck ran the light. BOOM kinda cool to see what happens when two Fire Trucks crash into each other.

[Exocetid]

It's all fun and games until someone gets hurt.

[kibukun]

I thought they work by weight?

[bguiles]

There is clearly some confusion here. Let's clear it up: a) The material of the small vehicle does not have to be ferrous or magnetic to trip the sensor, only capable of carrying current* (jury's out on the poorly conductive carbon fiber in those plastic bikes, but read on--it may not matter.) b) The strength of a magnetic field decreases as an inverse square log* (i.e. very rapidly in a very short distance) from a magnetic source, which in this case is the buried coil. c) The solution to the above is to either have a LOT of material changing the inductance of the coil, as the several tons of it found in a car. -OR- get that material VERY close to any part of the coil. Knowing all this led me to trying to test the hypothesis, but traffic lights are very un-scientific: "Oh i got this one in 3 seconds, but who knows if i tripped it or it's just timed?" UNTIL! I found, on my campus, a motorized swingarm type of barrier that swings up immediately when it detects a car with a--wait for it--BURIED COIL SENSOR! So I tested the theory with an aluminum racing bike with skinny, low mass aluminum rims. The nearest steel was the stainless spokes and the eyelets of the rim (kevlar bead on the tires. yeah i thought this through.) The result? When I carefully traced with my wheels a line RIIIGHT above one line of the sensor parallel-ly (i picked the right side)... the sensor tripped and the swingarm activated! And lo the heavens did open and the science gods did grin! And the prophet was able to reject the null hypothesis, and cruise smugly along his merry way! And... well... you get it. So, IMHO the case is closed. ANY metal (or conductive material, but since were talkin bout bikes, were talkin metal) will do, but it MUST be BERRY BERRY close to the sensor (and moving, almost forgot to say. just roll real slow.). Ideally, you're using the material in the rims of your wheels to carry that eddy current, not because it's big or steel, but because it's close!. Closer than a car's rim! Unfortunately this leaves out all you weight weenies and your Zipp carbon wheels, but that's what we get for riding plastic bike-shaped-objects now isn't it? Cheers to you all and good night!*** *it's the eddy current in the vehicle that induces a back EMF into the coil... or some such nonsense i learned years ago in physics. No magnets or iron required. **knocked back a few tonight before writing this, please correct if i've got the math wrong. ***not including said weenies.

[lucek]

great experiment. now all you need do is test a NdFeB magnet under the same conditions. I'd do it myself but I don't know where the closes example of thees are to me. (all the traffic lights I know are timed.)

[astrong0]

you are the coolest damn person I've ever been graced to read scientifically rant...

[bguiles]

aw shucks! even cooler than bill nye?? ...or richard feynman??

[capt.tagon]

Use your metal bicycle rims as a variometer secondary coil. Ride up to the induction coil, tilt your bike over 45 degrees with one of the rims near the coil and it will pretty instantaneously trip gate arms and stoplights. The round rim creates a secondary coil winding which when on the same plane as the induction coil, couples pretty effectively. With the bike upright, it has less effect as the magnetic field isn't cutting across the rim as efficiently. Variometer = variable coupling transformer with secondary mounted so it can turn through 90 degrees. Windings parallel, maximum coupling, windings perpendicular, minimal coupling.

[lucek]

This sounds like the rainmaker fallacy. If you wait long enough it'll rain anywhere. I really doubt the field from a NdFeB magnet is enough to make a difference. For another reason aluminum and stainless steel aren't farrow magnetic but they do produce a field with induction. For that matter the steel in a car doesn't have a field but will produce one with induction. This is why metal detectors don't just find iron, but all metals capable of induction.

[dreadengineer]

I think that's right; unfortunately I kind of doubt that this works also. If the sensors work by inductance, they won't care about the magnets more than any other iron. Magnetizing the iron inside an inductor doesn't change its inductance. (Inductors are about changing magnetic fields; any constant magnetic field has no effect.) The only mechanism I could think of that could explain why this works, if it does, is that maybe the moving magnet, when you first pull up, is inducing a small voltage in the coil, which could trick the sensor into thinking the inductance changed. That seems unlikely though. I would try timing the light a few times with and without the magnet to see if it's really making a difference.

[cbennett811]

would this also work at the drive through windows? most of the time when i pull up to the speaker they cant see me. so i always have to pull around to the pay window then they get all confused and probably spit in my food! it would b awesome if it works in the drivethru, but i think wendys still uses the scales. let me know if anyone has a tip for that.

[Super_pride1146]

If you ever find that they have spit in your food, you sue them for lots and lots of money. LOTS.

[beehard44]

and burgers. LOTS

[GenerationJ]

Sounds crazy, but I'm going to try this. My neighborhood has ONE traffic light to get us onto the busy coast-road that is the main drag. If you want to go across or left, you've either got to wait for a green light or turn right and make a U-turn on the busy road. Trouble is, the light often isn't triggered by smaller cars with a lot of plastics such as our VW TDI New Beetle. There's nothing more frustrating than sitting through three cycles of a VERY slow light before you realize you've got no choice but to back up, change lanes, and go right. (And no, nearly TEN years of reporting the problem to Oregon Department of Transportation) has not gotten them to fix it.) Anyway, I hope this works. Certainly no harm in trying it.

[malevolentsparkle]

i always thought that the lights here were done by weight. i may be wrong. anyone know? i live in auckland new zealand

[JermsG]

I thought they were done by weight, but maybe they've upgraded while I wasn't watching... I'll have to have a closer look at the next intersection I mosey past.

[qazxsw21000]

I did too, as it changes a bit faster when you pull on the line. I live in the US of A.

[Rishnai]

Installing a scale under the street costs far more money than running a loop of wire and then ignoring it until it is in that perfect state of maladjustment where nothing smaller than a medium car will trip it. So even though it's always the lighter vehicles that don't trip the loop system, it isn't actually by weight, it's by metal content.

[bob.smitty]

Actually it's not maladjustment, as the receiver can compensate for that. More often than not the small flex of the road under traffic, and the contraction through the seasons damage the conductor. As much as these things are a pain to install, you don't know pain until you have to take one out, particularly in an airport parking lot.

[Rishnai]

That makes sense. I always assumed that they ripped up the asphalt, put in a new one, and repaved. Is it more complex than that?

[abquid]

In the old days a lot of lights used a metal plate that was weight-sensitive; you can still see some of them around. But they've been almost entirely replaced by the wire/sensor type.

[Rishnai]

Excellent point. I probably should have said "installing a scale nowadays costs more than the wire/sensor type." Modern technology has changed quite a bit, and I don't know of any old-school ones remaining in Colroado. Of course, if someone finds one, I'm willing to ride several hours to go look at it...

[froggyman]

where i live they have cameras that sense when a big object comes up(like a car)

[zleebme]

you mean like motion sensors

[froggyman]

yeah, thats it, i just forgot the word i was thinking of

[randomray]

Few quality bicycles have ferrous metals in them to trigger a light . They are made from aluminum alloys , carbon fiber and plastic . The cables and bearings are the only steel and that's not all the time . Some K-Mart bikes are steel but not many and few people ride those on the road . Scooters and small cars may even have aluminum engines and lots of plastic . I was waiting next to a super-scooter " large style scooter/small motorecycle " on my bicycle and we needed a car to pull up to set off the light . While there I told him about putting magnets on his scooter .

[anjin12]

Bicycles have enough ferrous material in the crank set to activate the induction loops. see .... http://www.humantransport.org/bicycledriving/library/signals/detection.htm ... The technique taught is to position your bicycle on the outside edge of the loop with the crank set directly above the line. The other technique is to lean the bicycle over, bringing the crank set close to the edge of the loop.

[randomray]

The crank set on my bicycles are aluminum alloy and stainless steel neither of which are magnetic . All the nuts and bolts on my bike are stainless steel . More power to you if you want to lay your bike on the road . There are few bicycles in this country " I'm not worried about the others " that have very little ferrous metal in them . It has gotten so much cheaper to just use aluminum even on bikes where it doesn't matter . The only steel on my bike and lots of others is the chain . A lb. of steel for a detector that probably hasn't been adjusted since it was installed is not much . You guys are nit picking , they need more then a couple lbs of steel to work . With the present economy I doubt the first thing the road departments are going to do is adjust the auto-detectors every year so they can detect bicycles . Taping the magnets to your bike is a quick fix that works . If that isn't low tech enough get a ten lb. pipe wrench to carry . LOL

[Silence]

I like the pipe wrench... doubles as protection when some jack wants your bike :P

[ac-dc]

This is false. You may not have a steel frame but you have steel bolts, chain, and on scooters steel or other ferrous metals in the engine even if the outer block is aluminum. It may be true that some have too little metal to trigger the light sensor, my only intention was to inform that even on bicycles, MOST of them do not replace a lot of the steel with aluminum except on the frame itself. So -called weight weenies (Myself included) own a minority of the bikes on the road, perhaps 5% of those worldwide.

[Silence]

Its suffice to say, if a scooter with a steel frame, plates, brake shoes and electric motor isn't going to set it of, your bicycle isn't gonna stand a chance.

[npa4863]

or you could buy a REAL bike, you know like a Harley or nice little crotch rocket...lol jk

[Pfarmkid]

Ok I highly doubt it's a federal offence to change a traffic light if there's a wreck then yeah but if you just go and change light I doubt they even give a crap

[msmythers]

In our area in Florida they have to cameras. The cameras don't detect motion, they are inferred and detect heat from the car. I'm waiting for days when the temperature is over 100 to see how that works.

[trebuchet03]

They aren't detecting absolute heat - they're detecting relative heat ;)

[msmythers]

Some of the cameras are as much as 70 feet away and given our thunderstorms I would say relative but a car in rain will cool down much faster then asphalt.

[trebuchet03]

If the car is colder than the road surface... There's still a temperature differential between the road and the car ;) Remember, heat is not the same as temperature ;)

[whosdadog]

It isn't looking for a set temperature difference. Just a sudden change anywhere in the frame. The chance that the asphalt and the car are both the exact same temperature is very low. It will detect even a small change.

[wagnet]

If you choose to install a magnet on the bottom of your bike/scooter - be careful - as many new models use flash memory (e.g. thumb drives) to store the ECU programs that control the bike/scooter's programming - and the flash drives can be wiped clean by the magnet. Work with your bike/scooter's service department to make certain the magnet is far enough away for any sensitive electrical components.

[scotth61]

LOL!

[RainyDayInterns]

"...flash drives can be wiped clean by the magnet..." This is completely wrong. Please do not perpetuate the myth that Flash memory is affected by magnets. Google how Flash memory works and you will see that what was true for cassette tape, floppy discs, and other ancient recording technologies have no bearing on Flash memory.

[Exocetid]

Not true. It is perfectly safe to install a magnet under a bike as it will not have any effect on any electronic components on the vehicle, unless said vehicle has a fluxgate compass. That said, it will attract lots of ferrous metal filings.

[mgalyean]

Flash drives are non-magnetic. You must be thinking of floppy disks, or backup tapes, or hard drives.

[ac-dc]

Flash drives are not magnetic but a strong magnetic field CAN disrupt their function by corrupting data in-transit, or fouling the onboard power supply circuit. However, this would have to be a much, MUCH stronger magnetic field than some 6 lb neos on the bottom of a bike/scooter. 6lb neos on the bottom of a scooter won't even effect magnetic tape, much less a hard drive if more than inches away from it.

[Kasm279]

Hard drives are non-magnetic as well. However, Zip and Super Disks (basically floppies) are magnetic as well as miniDV tapes (learned the last bit by leaving a tape under my old CRT monitor >.<)

[killersquirel11]

Hate to break it to you, but hard drives are magnetic

Wikipedia

[Electronics111]

It's not magnetic. IF you sa it is that's why there is a super powerful magnet for the arm and magnets in the motor to make it work right t=next to the platters. You would need a REALLY big magnet to affect a hard-drive. although any type of shock while the arm is not parked in the safe position can damage it and cause the heads to crash onto the platters.

[killersquirel11]

"Data is encoded magnetically by read/write heads..." - from the article I linked

The reason that the other magnets in the hard drive don't have any effect on the hard drive is that they are enclosed in a metal known as mu metal, which basically blocks the magnetic field.  You don't need a really big magnet to mess up a hard drive, if you take the magnets from another hard drive's actuator and put one on each side of another drive while it's running, you will probably lose most of the data on the drive (although you might be able to recover some with work).

Although if you really want to wipe a hard drive beyond all hopes of recovery, hackaday shows how to use thermite.

[Kasm279]

Bah, someone told me they weren't for some reason. I guess i should have checked first >.>

[thinkdunson]

indeed

[HARaaM]

Ok, this is not an 11.6 strobe per second or what ever your local code is Opti-con over ride device then, Good.

[docslip]

This is a pretty smart instructable. I would like to share some inside details of this technology that may be of some benefit. The image shown Step # 1, of the roadway with an inductive loop installed is known as a quadropole loop. It is not the actual detector just the inductive sensor that connects to the detector amplifier via shielded cable. The detector amplifier is usually located in the traffic signal cabinet where a traffic signal technician will have tuned the amplifier to achieve a number of goals. Reject false acuations and yet be sensitive enough to reliably detect the 'PRESENCE' of an approved class of motor vehicle. Depending upon the policies of the traffic signal department in your jurisdiction, the presence of bicycles may not be a high priority if it will cost big dollars to achieve. Scooters and Motorcycles are treated usually as motor vehicles and reliable detection may well be a requirement. As the author points out, modern small vehicles have less iron in them then in the previous decade making detection somewhat more difficult with inductive loop amplifier technology such as the Caltrans 222/242 , and applicable NEMA standards* . The cost of installing new loop geometries in the roadway is surprisingly high as in many cases , flag people or Police are required. Remember this one detail - The detection works on the basis of "Rate of Change of inductance" implicitly or explicitly. This means that if a vehicle should park or stall over top of a large loop , for example, the amplifier must tunes it out to be useful. The remainder of the physical loop will become active again after some pre-programmed time frame. ( 4 minutes perhaps ) The loop amplifiers in the cabinet can range from <$100 to > $500 depending upon features and where they are acquired. I messed with this sort of application ,about 15 years ago and found certain loop geometries could not reliably be fooled by driving over them with a permanent magnet. It also depended upon where exactly on the loop geometry the magnet was passed and also it's linear velocity. Obviously zero velocity produces no interference signal. A quadrature wound high frequency focused transponder was born from this requirement and a means to detect transit vehicles utilizing existing loop/amplifiers was born. There are many ideas floating around as to how traffic detectors work. Without an inside source for the details I am both surprised and delighted to see how close many of you have come to identifying the actual theory of operation. Congratulations are in order because that is what the pioneer scientists did ; they observed and they deduced. -

[janettetsmith]

One time a state trooper had to take me home and he had a button on his dashboard he pushed to change the lights to green. Took no time at all.

[garrettmikesmith]

its a system based on infrared pulses of light, which get picked up my a receiver at the light. its the same technology that's inside the remote control for your tv.

[madduxm]

May be a federal offense to use a MIT http://www.i-hacked.com/content/view/176/44/

[janettetsmith]

Well, then it's a good thing that trooper didn't try to sell his to me. I would have just told him no thanks. If he did try to sell me his apparently he did not know about the federal offense thing, so I would mention that to him, too.

[abarrow]

Those are flashing lights directed at sensors on the stop lights that cause them to change to green for emergency vehicles. As of a few years ago, not legal (federally) for private individuals to own. For a short time, before the law was enacted, a few companies were making such devices that fit on the front of your car. You can imagine the chaos if a lot of people owned and used them.

[Tampaguy]

I believe what you are saying. But I'm pretty sure that the device the Trooper used was based on higher technology, and likely in urban areas where traffic lights (and the flow of traffic) is 'computer controlled'. Anybody care to expand on this?

[janettetsmith]

Yeah, I figured it was some gadget saved for special people.  It was ages ago, so probably more on the very low side of today's high tech scale.  It was, however, a rural area, well sort of in between where civilization meets country bumpkin.  It was Highway 90 where it passes by the Imperial Sugar plant in Sugar Land, Texas.  :)

[mongojr1]

The lights are set on timers that are in a control box there are no scales in the road but there is a optical sensor that tells when you are at the light

[Kasm279]

There are four different types that I know of. Induction (as this 'ible shows,) Pressure, optical (what we have here, has a sensor up by the lights) and then the old timed ones.

[Sam Grove]

Perhaps they meant it was a metal mass issue.

[iamchrismoran]

some lights, sure. I was stuck at a light one night for 6 cycles until a car came... I should have just run it. The next day I called the town clerk to inform them of it and they said it WAS a weight issue and that they could adjust the tolerance.

[onlylooklikepackrat]

Thanks for the insight. I live in San Antonio, TX and most all the lights here are dumb as dirt....not even an inductive loop, they are simply on timers!!

[numenius]

Here in the UK I've noticed there are often 2 sets of loops - one further back to alow biasing in the signals when there is more traffic queueing in that direction. I've found out by trying when there's no traffic around, that if I stop my vehicle on the *first* one, ( i.e. the loop furthest from the traffic lights, not the loop nearest the lights), as long as I stop for a few seconds, it seems the system thinks there is a queue of traffic and changes to green quicker. I've tried this out several times to make sure it was not coincidence, & I use it regularly on a local single-track bridge and a junction I use late at night when I'm on shift - where I'd often otherwise be sitting for a few minutes at a red light while there is no-one coming the other way ! Not all sets of lights seem to have two sets of loops on the approach though.

[Steve66oh]

Exactly right! I always stop my car on the first loop I come to. If a second car comes behind me, I move up enough to let him sit on that loop. By then, the light is usually green. Around here, the double loop is often seen in left-turn lanes, where the system decides whether OR NOT to give a left arrow at all, based on demand in that lane - the engineers seem to feel that one car can do without the left arrow, he'll get across after the opposing traffic is through, but by triggering the arrow, I get across first.

[Kozz]

I posted this idea once at Slashdot and got a schooling. http://slashdot.org/comments.pl?sid=1674662&cid=32458576 So, who's right? or am I misreading/misunderstanding either this instructable or the slashdot comment?

[annaliesa!]

why not put the niobiums on the bottom of your shoe? Then you could put your foot down on the line when you want to let the light know you are a vehicle waiting for your turn? Just a thought, its still early and this post is very old (2008) so never the mind. :P

[Spectrace]

AWESOME!... this should work with bikes too? except what i would do is put it in my shoe while riding and instead of being by the crosswalk, be in the road and get a greenie all the time... sweetness... great structible.

[Kipkay]

No, you need to have it low and stay there. There is another Instructable about putting magnets in your shoes, but why not just attach it permanently to your bike?

[Spectrace]

ok, but i think you may have misunderstood me slightly. with it in your shoe (not on motor scooter or w/e) riding a bike, you just lay your foot on the coil and it should work. shouldnt it?

[EarlyGrayce]

It would work but you would nees it in your shoe while riding which is easy to forget. With it mounted on your bicycle ity will always be with you when you are riding

[EarlyGrayce]

Our local Road authority uses a cylindrical bar of metal 8 inches long and 1 inch across to calibrate the sensor. If you haven't access to strong magnets then a piece of metal similar to the one I mentioned will work too.

[aurical]

Nice instructable! I think in North Carolina (RTP area) they a mixture of induction and motion sensors. I commute by bicycle and I've noticed that certain lights seem to change without cars to trip the light. At first I thought I just got lucky, but it happens regularly a few lights in my neighborhood (where there are a lot of bicylists). Unfortunately they aren't very common and I've been thinking about getting magnets for my bike.

[RelientOwl]

I dont think all traffic lights have this...

[Tom Buckey]

does this work in the u.k?

[teddybear230]

Most UK junctions use inductive loops therefore this should work. However, most newer junctions have been configured to be sensitive enough to be triggered by bikes. Also some older junctions may only have the sensors mounted above the lights. I presume these can detect cyclists as they are also used to see if there are pedestrians crossing the road. Again I'm sure some are more sensitive than others.

[harrty]

There is something exotic about the traffic lights that "know" you are there -- the instant you pull up, they change! How do they detect your presence?

Some lights don't have any sort of detectors. For example, in a large city, the traffic lights may simply operate on timers -- no matter what time of day it is, there is going to be a lot of traffic. In the suburbs and on country roads, however, detectors are common. They may detect when a car arrives at an intersection, when too many cars are stacked up at an intersection (to control the length of the light), or when cars have entered a turn lane (in order to activate the arrow light).

There are all sorts of technologies for detecting cars -- everything from lasers to rubber hoses filled with air! By far the most common technique is the inductive loop. An inductive loop is simply a coil of wire embedded in the road's surface. To install the loop, they lay the asphalt and then come back and cut a groove in the asphalt with a saw. The wire is placed in the groove and sealed with a rubbery compound. You can often see these big rectangular loops cut in the pavement because the compound is obvious.

Inductive loops work by detecting a change of inductance.
If you were to take the inductor out of this circuit, then what you have is a normal flashlight. You close the switch and the bulb lights up. With the inductor in the circuit as shown, the behavior is completely different. The light bulb is a resistor (the resistance creates heat to make the filament in the bulb glow). The wire in the coil has much lower resistance (it's just wire), so what you would expect when you turn on the switch is for the bulb to glow very dimly. Most of the current should follow the low-resistance path through the loop. What happens instead is that when you close the switch, the bulb burns brightly and then gets dimmer. When you open the switch, the bulb burns very brightly and then quickly goes out.

The reason for this strange behavior is the inductor. When current first starts flowing in the coil, the coil wants to build up a magnetic field. While the field is building, the coil inhibits the flow of current. Once the field is built, then current can flow normally through the wire. When the switch gets opened, the magnetic field around the coil keeps current flowing in the coil until the field collapses. This current keeps the bulb lit for a period of time even though the switch is open.

The capacity of an inductor is controlled by two factors:

• The number of coils
• The material that the coils are wrapped around (the core)
  

Putting iron in the core of an inductor gives it much more inductance than air or any other non-magnetic core would. There are devices that can measure the inductance of a coil, and the standard unit of measure is the henry.

So... Let's say you take a coil of wire perhaps 5 feet in diameter, containing five or six loops of wire. You cut some grooves in a road and place the coil in the grooves. You attach an inductance meter to the coil and see what the inductance of the coil is. Now you park a car over the coil and check the inductance again. The inductance will be much larger because of the large steel object positioned in the loop's magnetic field. The car parked over the coil is acting like the core of the inductor, and its presence changes the inductance of the coil.

A traffic light sensor uses the loop in that same way. It constantly tests the inductance of the loop in the road, and when the inductance rises, it knows there is a car waiting!

[porcupinemamma]

Veeeeeeeeeeeeeeery interesting! Thanks. :0)

[josehooker]

do anybody know about ignition coil does that part make the spark

[bob.smitty]

It's a transformer that is fed in pulses, with a steep ramp up. The counter current of rupture generates a rush of current through the primary coil which induces a charge on the secondary one of almost the same power but at much higher voltage (and proportionally lower current.) Some of the new coils are almost 98 % effective.

[Ashinka]

At the end he says "Save time, gas and Frustration" How can you save Frustration? Other than that This works, I did it to my Dads bike, but My Magnets are rusted up because I count find any rust proof casing.

[bob.smitty]

you can spray paint them... Home Depot has house brand for under a dollar a can.

[Father Christmas]

coat them in rubber cement lol

[candle360]

um... some sensors arent conductive sensors, they're actually WEIGHT sensors, meaning, your car doesnt weigh shit, you're gonna get stuck there till something pulls up close behind you or next to you, I found this out because my Dad had a small scooter, and everytime he pulled up to a light, if he was the only one there, it usualy wouldnt go off, so he would have somone drive near him, because of the weight. his scooter, because some of you will say something, is full iron, a very conductive material, and it should trigger the sensors, if they are conductive sensors as you say

[bob.smitty]

You are confusing weigh stations with sensing loops. The loops are coils; they are inductive sensors, not conductive (what is a conductive sensor?)

[Rock Soldier]

At most traffic lights and turn signals

You and your probally didn't/don't live near traffic lights with the sensors, so that may be why the light didn't change.

[ParkerK]

They're never weight sensors, that's just an assumption people make. It would be too expensive and ridiculous to install scales at intersections.

[candle360]

well how is it that my dad's scooter, the frame completely made of iron, did not set off the sensor at the stoplights?

[froggyman]

well, a car would probaly have a little more iron/ ferrous material to set off the sensor...

[-Aj-]

they are weight sensors, not scales. they use a pad full of liquid or gas and when a vehicle passes onto it it compresses it a fraction and it is measured by a pressure sensor. these are mainly older ones it seems and many now are inductive sensors instead. so there is a mix

[bob.smitty]

This is funny! There is no mix, anywhere in the world, because the sensors you describe were never used to sense traffic anywhere. The old way was to use coils, which weren't that easy to install anyway, and they have been replacing that with other types of non-contact sensors in most commercial applications. Although I'm not sure what they are doing in public roadways it stands to reason they would try and replace them with something more durable and easier to install.

[hammer9876]

I got stuck behind a big 18-wheeler truck in a left-turn lane one time. As near as I could figure it out, he pulled out too far to make the turn then chickened out. His trailer was straddling the sensors, i.e., no weight on the wires, and the light would not cycle through to allow him to legally turn. I finally changed lanes (probably illegally) and went straight through the light. After I legally made a u turn and came back to the intersection, I saw that he was still sitting there helplessly. I have wondered what he had to do to get out of that situation. Like wait until 3 am when the traffic cleared. Ha!

[killerjackalope]

It's because the undercarriage of trailers is in some cases just too high up so the sensor won't pick up, more often than not something hanging down is enough but unless they use the pricier heavy beaded radials the tyres won't trip it and keep the rims far away, or at least that's the theory...

[Hands Without Shadows]

A scooter is not as full of iron as a car......

[candle360]

yeah, but that scooter, that's about 3 inches from the ground should have set off the sensor, because the frame is made completely iron

[ac-dc]

A scooter is usually made of tubular or otherwise hollow steel which (relative to a car) has much, MUCH less iron.

[candle360]

well, a car is also made of tubular steel, much more than a little scooter yes, but my dad's scooter was from the 80's, when everything was still made from iron, so the cunductive material in his scooter should have set off the sensors, if they were running properly

[bob.smitty]

Your scooter weights in at what? 300 lbs? Your average car is 3000 lbs, mostly iron and steel. It is not the conductivity that sets off the coils (for example, you could put 2000 pound block of aluminum there and nothing would happen.) While the sensors can be adjusted to measure smaller masses, not sensing your scooter does not mean they are not running properly.

[abross]

Another thing you have to consider is how much space the metal object takes up in relation to the coil. If you have something as wide as a scooter compared to a car, the distribution of the iron in the frame drastically changes. When you have a larger surface over the coil the inductance of the coil will change.

[ac-dc]

It must've been quite a bit older than the '80s if it were actually iron, I doubt there were even any made that were iron framed, by then scooters were made of steel, like Crome-Moly. Granted, steel is refined iron with additives, a magnet would stick to it. Otherwise as you already stated it is a lot less steel than a car, and the issue we've already covered is the quantity of it being insufficient to set off sensors.

[Aquadag]

I don't think you need magnets or iron. I once made a copper wire loop about 1 to 2 feet in diameter and while I was on foot, I placed it over a detector loop for a parking lot gate. The gate opened right up. Not sure how small a loop would work. I think I soldered the ends of the wire together.

[bob.smitty]

I'd be interested to know on what principle an open (or closed) coil would work as you describe. I'm trying to keep it nice, but I find it hard to believe that you can't remember if it was one foot or two feet across and whether you soldered the ends together or not. In the nicest possible way, I call bullshit.

[Colonel88]

you dont need it at all :) just wait. be patient because i am 85% sure that in the video the light was close to turning green and that the thing didnt work at all.

[jamesrocks]

were can u buy those magnets

[Colonel88]

they are expensive

[jamesrocks]

(removed by author or community request)

[ieightu]

it doesnt matter on what vehicle you drive. what matters it that it needs to be able to change the frequency

[Jocorki]

where i live (Los Angeles) they are circles not rectangles and for turn arrows the circles are 3 to 4 car lengths away from the limit line. that's why when their are a lot of cars behind you their is an arrow but when its just you their is no arrow.

[ultramegabob]

another thing you could do would be to install saddle bags and fill them full of scrap iron.

[TigerNod]

Hehehe, smart, very smart. Did you discovered this yourself or did you just learned it from someone else?

[zleebme]

I think that there is an instructable on it

[jedB]

This looks like a parallel mount rather than a perpendicular (ie Vertical)

[lincomatic]

what he means is orient the N-S poles perpendicular to your direction of travel.

[Constantine]

Lol... What a load of hooey. FYI, magnetic fields diminish very quickly the farther they are from an object. Even on these magnets it probably doesn't go more than half an inch or an inch..

[ac-dc]

Untrue, a compass will show you that.

[Constantine]

(removed by author or community request)

[ac-dc]

Then why did you reply? A compass will show the field extends further than a few inches, and a street stop light indicator can rely on less than strong magnetic fields because it only needs tuned to not activate based on the natural earth magnetic field. Remember, they don't randomly make a crude thing, they tune it to the desired threshold. Granted, this Instructable is evidence they may not have tuned it well enough, but merely being unable to make ferrous objects move based on magnetic pull vs gravity or friction, is not evidence a magnetic field isn't strong enough to be detected.

[lyzyrdman]

And timed traffic lights that are timed for the speed limit are also timed for twice the speed limit..

[phillyeaglesfan2010]

HAHA just saw this instructable on Brink (new science channel show) Congrats Kip Kay!!

[Rob K]

Haha you beat me I just saw it a few minutes ago. 11:30 central time.

[PKTraceur]

Nice one, Kipkay. I didnt even have to look at the stats box, I just had to listen to your commercial voice... lol.

[attilam]

The other thing you can do on a motorbike or scooter is turn the engine off, then use the starter motor. The field of the magnets in the motor will fluctuate as it spins, and it can be enough to trigger the system...

[roadking05]

The magnet is total B.S. I used to install traffic signal loops in Cleveland,Ohio. for local 71 I.BE.W. The wire is by Ohio code 4 inch buried in the road.There is no way a friggin magnet is going to trip that signal. It is all. It is all weight. A lot of time if the wires are to close to the surface by the curb where they go to the controller on the street corner. Snow plow will rip into them an that will disable the loop. Some cityieswill over ride the loop to control the flow of traffic etc,... A magnet to effect an electrical field like that you'd be picking up all kinds of loose steel along the road.

[kelseymh]

As an alternative to using a strong B-field to cue the inductive coil (legal in California, at least, where using an optical frequency strobe is not), you may also look for a smaller, bicycle-specific pickup coil installed either in the right-hand lane or in the dedicated left-turn lane. These are typically denoted by a bicyclist stencil with a forward arrow on the pavement, and a much narrower (~ 1' x 3') groove where the pickup wire was embedded. The smaller coils are specifically designed to respond to bicycles and scooters.

[bugman1470]

Another way to trigger the traffic signals for you fellow bikers out there, When you come up to a ground loop, put your kickstand down on top of where the wire is. This will disturb the magnetic field and start the timer to change the light. Safe Biking! Steve

[abquid]

I'm not sure that this works-I've been at some lights, leaned the kickstand down on the sensor/wire and still no luck. Of course, the sensor could have been broken. There's one light in particular where the kickstand never works--I'm going to try the magnet trick and see if that gets it to change...

[Rishnai]

And then remember to put it back up when the light changes!

[eecharlie]

I think what actually trips the sensor in this case is tilting your bike frame - you don't need a kickstand at all. As I understand it, the sensor coils send a current pulse which induces a current in any conducting loop above the sensor and *oriented horizontally*. The induced current then produces a field of its own, which induces a current back in the sensor coil, and that's how it senses. A bike frame looks like a vertical conducting loop, relatively speaking, so tilting it over makes it horizontal enough that it can interact with the sensor. It's the (projected) area of the loop in the plane of the sensor/road that matters, i.e. the area you'd see enclosed if you were to look at the shadow cast by the bike from an overhead light source. This area goes from nearly zero for an upright bike to big enough to be measured if you tilt your bike frame over by 20 degrees or so.

[bengerszewski]

YOUR VIDEOS DONT SHOW UP FOR ME!!!!!!!!!!!

[gsdkain]

Then you should install "Adobe Active X Flash Player" or uninstall then reinstall Adobe Active X Flash Player

[l)eM()N]

thought of a funny idea lol drop a msgnet on top of cement where the wire is

[hammer9876]

That's what I was thinking! Before I read through the instructions above, I was thinking of a magnet tied at the end of a string. Then, like a yo-yo or something, you drop it to the pavement, troll it around until the light changes and reel it back in. The instructable turned out to be much more elegant than my imagination. Five stars.

[sooners1]

Neodymium magnets can be purchased on ebay pretty cheap

[TheDeepFriedBoot]

The frequency that changes the lights is 14Hz. Most lights in major cities though are setting up encryption on the lights since people would go out an buy a MIRT device and change the lights themselves. Using these systems is illegal if you are not approved. Therefore I am only posting this information for discussion and spread of knowledge, not for it to be abused.

[bowmaster]

You can get 800 pound magnets at unitednuclear.com. They mess up any eletronic device in the room!

[mccoy colby]

if ther is no possible way to get Neodymium magnets could I use another kind? what about allot of standard magnets?

[manga-ka]

I wonder how many illegal Instructables there are on here? Including this one.

[nightsky2431]

Since when is putting a magnet on a bike illegal? How can you prove malicious intent?

[jridley]

There's not a thing illegal about this. All that they're doing is making the inductive pickup register a light vehicle. In reality, the pickups are SUPPOSED to be calibrated to register any legal vehicle on the road, including motorcycles and bicycles. Many are not, and some road commissions won't fix them, so this equalizes things. If this were an instructable for building one of those flashers that ambulances use to force a green light, THAT would be illegal.

[vanbo]

Quite a few.

[farbzilla]

Its not illegal. you are not stopping the light from changing its normal cycle. all you are doing is making the sensor know that there is a vehicle waiting to be signaled to go. The other method that emergency vehicles use disrupt the cycle of the light by overriding it. That would be illegal if used by a non emergency vehicle.

[bigcat]

It isn't illegal to put magnets on a motorcycle to trigger the sensors at stoplights. What is illegal is using the "Opticon," the flashing light that police and fire use to change the lights to green. The sensors are set up to detect cars, but aren't sensitive enough to detect a motorcycle. There's more metal on a car than a bike, so...... So if you have a small motorcycle, like I do, you'll wait forever for the light to change, unless you put the magnet on the bike, to trip the sensor. All you're doing is tricking the sensor to think that you are actually a car.

[Kipkay]

I don't know. But all of mine are illegal. Enjoy! LOL! Idiotic. What are you an attorney?

[manga-ka]

Nope...just really bored

[TCPMeta]

Nice little trick. Theres also another way to get a instant green with out waiting for the timer. A lot of citys that haven't converted to use LEDs instead of bulbs can be tricked or in heavy traffic areas. Emergency vehicles use a type of light signal that has a range of 25 to 50 yards and will make a red light turn green. This can be copied using a strobe light but you have to find the right timing for the light.

[Dubi01]

the emergency vehicles use a special strobe that is unique in strobing frequency and temperature. Different states use different specs. Off the shelf strobes don't work in 90% of the states, and as usual, it is illegal to use such devices by anyone but emergency vehicles (ambulance and fire engines), not even police cars are allowed to use these devices.

[jridley]

Now THAT is illegal as heck, and if you DO get caught, you'll be in a world of hurt. NOBODY is going to be kind to you in any way, from the officer to the judge, they're not going to be nice about it. Just not worth it in any way. Besides, it's a pretty pathetic display of "I'm the most important thing on the face of the earth, your job is to get out of my way" isn't it?

[gsdkain]

LOL. Hello, what world do you live in? Most people I know are like that. Sad isn't it?

[blacknkhak]

forgive me if im wrong but the point this person is trying to make, has more to do with the fact that scooters don't have enough metal to trigger the sensors that detect cars waiting for a light. what that means is that a scooter or other "light vehicle" could sit forever in heavy traffic waiting for a light .
All this magnet does is indicate that a vehicle iswaiting to "go".

[Slammer]

It's called Opticom and its marketed by 3M. A cabinet is attached to the light controller and it logs preemption requests. Although 3M will tell you that its impossible to reproduce their emitters (had an argument at a trade show with a 3M guy) it is quite simple to do. Opticom works with both traditional and LED traffic lights. That said, the request is logged, and you will be caught if you try it. Depending on where you are, you will likely lose your license so its not worth it.

[glidewave]

This has nothing to do with Opticom or any other method of "activating green"... this is simply increasing the footprint of the scooter/cycle etc.. by using magnets to trigger the induction loops' normal process when a car is present. The IR systems like Opticom can be triggered using an IR transmitter like emergency vehicles have (not all); however using the IR transmitters are highly illegal...not just loosing your license, but federal fines and possible prison. That said, search the web, there's sites that have information on how to use a specific type of IR remote control (TV) and key combo to trigger the IR sensors :)

[TCPMeta]

You'll only get caught if theres a cop near by or if the light has a camera witch in the city of Jacksonville doesn't have due to some privacy act. Nine times out of 10 there isn't a cop around and it comes in handy is you own the same type of vehicle the police use.

[theadamlevy]

shes a witch!

[foxcross]

I've ordered 4 Rare Earth Magnets; Grade N40 (Block - 2.000 x 0.500 x 0.125) each having a pulling force of 12.06lb/5470g. I'm gonna give this a shot for sure, since having a solid alum. frame and rim mountain bike kind of kills the options of putting a kick stand down or putting my rim above the under-ground coil of wire. I'll be sure to post my findings, FC~

[bossfish]

As a long time bicycle rider doing thousands of miles cross country touring, I have been stopped at an intersection with an unchanging light more times than I care to count. Most towns and cities have lots of them that are mal-adjusted and few towns care. A magnet might help, however I found a simple strategy that worked MOST of the time. That is to carefully ride slowly on top of one of the grooves cut in the pavement along the direction of road travel and then stop with your bike wheel as close as possible to the center of a cut, right over the buried wire. The metal rim of your wheel, which is also part of an electrical loop, now is closely "electrically coupled" to the buried loop and therefore increasing the load on the sensor significantly. It usually is enough to trigger even the most mal-adjusted circuit. The bike wheel is like a "shorted transformer" winding only about 2 to 3 inches from the sensor coil which is actually a much bigger load on the sensor circuit than most car frames and engines located at 18 inches or more away. The "reluctance" change of the sensor is reduced by the square of the distance away from the load so that means the load caused by the bike wheel 2 inches away is about 81 times greater than a auto engine at a distance of 18 inches!

[Rishnai]

Excellent trick! Apparently I've used it a few times without even noticing. Unfortunately, most of the intersections (except the worst-maintained) here in Denver don't have a visible loop, since they've paved over it. Therefore, lining the front wheel up would be tricky if not impossible. Sometimes if all else fails, it seems like the best way is to wave the car that pulled up behind you to come even closer, until that trips the light. One time I was driving in my car and a guy on a real tiny scoot got in front of me just in time for us all to get stuck waiting for a green arrow. He wouldn't pull forward enough to let my car trip the sensor, and he wouldn't admit that the bike he was on was just too dang small to trip the light. It took five cycles of not getting an arrow before he swallowed his pride and pulled forward enough to let me trip the sensor with my car.

[FireBAT]

I've thought about trying this for a long time- I used to ride a Goldwing, which would usually trip most light sensors, but now I have a Triumph Sprint, which is more aluminum and plastic than steel. Great Instructable! Also, here in Pennsylvania, it is not illegal to activate the sensors and get the lights to cycle, the way the magnets do, but it is VERY illegal to trip the Opticon system using a transmitter, even a universal remote. When the Opticon is activated, a white spotlight above the traffic signal comes on and stays on for at least a minute, letting everyone at the intersection know the light cycling was overridden by the Opticon. I'm a 17-year veteran firefighter. Our department looked into buying the transmitters to use in our neighboring municipality, and found out that even unauthorized emergency vehicles can be cited for using them.

[swtmama]

I'm not a tech but I was told by a highway patrol if you just flash your highbeams at the light as you approach the light will change. I haven't tried it on my scooter yet, I'm just learning and still working on a good balance (lol, but it works in my car. I passed it on to a school bus driver that was getting delayed by a country stop light and she said it works great for her. I'll have to try the magnet on my scooter! Thanks! V

[jdelamater]

If you look at snopes.com you'll see that the lights things isn't entirely true. If you flash them REALLY fast then it might work, but most headlights aren't capable of replicating what emergency lights can do.

[bmxmike]

It is somewhat true, it has to have a sensor at the top of the light and the light must flash rapidly and at a high angle. They are most of the time used for emergency vehicles approaching a intersection and cause just the approaching light to be green. Police cars have them too but you can't see the light. If you look in the windshield you may notice a little box mounted as a high angle. This is actually a strobe light the flashes at such a high rate of speed that you can't visible see the light. They actually have the units for sale online.

[jridley]

Depends on the light. They just installed some camera based lights in one town around here, and it definitely looks for lights. Others look for metal rolling over the sensors. Old lights just change at a regular interval regardless of traffic (yes, those still exist).

[Derin]

in the town i live here are the specs of the lights in the center: led-usage in-light timer timed intervals no detection cross-the-street button

[Derin]

here ar the specs for my neighborhood: incand. timer separated timed no detection no crossing button(i live on a highway which does not have sidewalks)

[winstonsmith2600]

I haven't seen a stop light that this would work on in ages. The stoplights in my town are only camera operated. They do not work at all in the rain and revert back to a very long timed sequence when they can't see.

[uhsnamih]

hi nice trick ...........aaaaa .........do we have this things in canada or usa

[mikeasaurus]

We definitly have these all over the place in Vancouver. I ride a motorbike and it triggers the light for me no problem. My bike I'm sure isn't heavy enough to trigger them so I feel confident saying that the trigger is magnetic and not by weight.

[Hockeyhero4]

Sweet, Since Gas prices are rising I recommend this for Motorcycle Lovers!!

[jridley]

Actually, step one and only is to report the defective light to the road commission and get it fixed. If the light does not trigger for your vehicle, then you are allowed to proceed through the light after traffic clears; just be sure that you can prove it. Usually when I see cars "stuck" at lights it's because they've pulled so far ahead of the white line they're no longer on the sensor, or they're so far back from the white line they're not on it yet. I actually had to get out of my car once and tell the driver in front of me to pull up on the sensor; we'd been there for 5 minutes. She had no idea that traffic lights even had sensors. There was only one light in my town that didn't trigger for my bicycle. I reported it, and when I hit it a week later it was triggering fine. Of course, they're now switching to camera-based lights instead of loop sensors.

[maeve]

We dont have any of these things in Ireland- The lights change at regular intervilles

[killerjackalope]

They exist here, definitely over most of N.I. and I've seen them in dublin, the busier parts of donegall and a few random places. Also ever notice that Dunfanaghy has like no traffic lights.

[spencerkaitlin]

I've reported a few lights and nothing has been done about them. I believe it depends, on the town/county/state that you are in, how fast and responsive your road commission is.

[jridley]

Well, then run the light once traffic has cleared. You're legally allowed to if the light is broken, and if it doesn't trigger for your vehicle, then it's broken. Since posting that last one, I've pretty much determined that the new intersection in town, which used to have inductive loops and worked with my bike, now has a camera which doesn't. It doesn't change until a car pulls up behind me. It'll be interesting to see if they fix this.

[spencerkaitlin]

Now what I want to know is whether that is a federal law or if it varies by state/county. I've heard conflicting stories. I suppose I could always call, but it's not enough of an issue for me to do so.

[Kipkay]

This only simulates a vehicle and triggers the normal detector as if it is seeing a car. Nothing illegal. Nothing to worry about. There are products sold in the US that do the same thing.

[jridley]

I don't think he's talking about whether this device is legal, he's asking whether it's legal to run a red if the light is broken and doesn't detect your vehicle.
I *believe* that it's in the uniform vehicle code. However, that's just a guideline. States are free to rewrite pretty much anything they want to, but they rarely do. It's worth checking into.
Also, do not ask a cop. Many do not actually know the vehicle code very well at least as far as unusual situations. You want to go find the vehicle code for your state and actually read it. It's amazing how many people will swear up and down that the law is something different than what's on paper; I've heard multiple stories of people who are SHOWN THE LAW ON PAPER and still say "well, that's not right."

[spencerkaitlin]

she* (haha)

Alright, well in my line of work I deal with Highway Patrol as well as Police so I will give asking them a try as well as looking up the law (if I can find it).

Thanks for the info, guys.

[coweater]

If your vehicle doesn't have enough to trigger these detectors (ignoring some exotic vehicles or possibly carbon fiber bicycles) then they haven't been installed properly. Their maintainers may or may not have sympathy with you to adjust them properly.

[Alexdc]

Why mount the magnets perpendicular?

[wasgij]

i think thats illegal in Australia

[danpayton]

Wow. Its always interesting to read a forum.. people get so bent out of shape over nothing!. Maybe I can help... Here's the way they work.
ANY traffic light with vehicle "sensors" is looking for metal. They bury loops of wire in the ground in front of the intersection... youve probably seen them... they are just like a metal detector you buy at radio shack. They have to be tuned to work properly. BUT at times, they can get out of tune, or wernt tuned correctly to begin with, and smaller metal opjects.. like bicycles, mopeds, or motorcycles wont trip them. Just like when you are using a metal detector, you have to constantly tune it. That's all it is. A metal detector. Nothing more. It uses magnetics. It has nothing to do with weight - If you think about it, ANY weight sensor or load cell would be constantly wearing out, and needing replacement. Not to mention water, freezing, and the fact that pavement changes shape with use. So, if you put a super powerful magnet on the bottom of your moped, bicycle, or fiberglass corvette, you can bet the metal detector is going to pick it up a lot better!
Hope this helps! now im going to shut off my computer and interact with the real world... :^{) Have a good day! Cheers!}

[eBandit]

danpayton has it right on. They are designed to pick things up like an engine block, frame etc... The smaller the vehicle the less likely to pick up and vise versa. It has nothing to do with weight like some seem to think. Small scooter equals less mass/less metal and vehicle equals a larger mass of metals. It would not be cost effective to have weight sensors installed in the ground at traffic lights. This isn't a bad idea to try for motorcycles, I've had to run lights because my bike never triggered them. I think I might try this out as soon as I buy another bike. All in all this is a good idea IF it does work because anyone with a motorcycle should know, not all sensors will trigger for your bike.

[inkymoses]

hi there guys just new to this so go easy . i noticed the posts about traffic detector loops i work in the loop detector industry as an installer so hopefully i know my job ;-) traffic loops are cut to a depth of 4 inches , a heat resistant cable goes in , on top of that we put a hardener in called epoxy resin then its all topped up with hot tar ....hope this helps guys

[FireSnake]

i liked your idea, and you taught me that some lights are controlled by magnetics, thank you! i was under the impression that it was activated by weight. i have a much more mischievous method: use a laser pointer at the light sensors (on the stop lights) that are installed for emergency vehicles, of course, if the stop light has on of those.

[BentSlightly]

I used to get the lights to turn green by flashing my brights a few times about 100 feet away from the intersection.

[G33k]

you can get those magnets in a hard drive, but keep them apart though, once they stick together it's going to be hard to split them!!!

[1zork]

Opticoms are also another option, although usually reserved for emergency vehicles. Very illegal in the US to trigger if not authorized, not sure if actually illegal in Canada.

[I)AVI)]

The magnetic field will INDUCE a current in the sensors, thereby assuring (most of the time) that a smaller vehicle may be noted, and the traffic light algorithm begun... but it will in no way "cause" a green light: and if it DID override the algorithm (as emergency vehicles do...) it would be illegal.

[royalestel]

Semantics.

[woodyhardon]

this does not make sense. the loops only detect cars..NOT give you an automatic green! Emergency vehicles have an ifrared light that works with a sensor on street lights for immediate green lights. The road loop sensors do not work in the same way. You may still be waiting for a normal light cycle to complete even when sensed. Otherwise...the lights would constantly be changing willy nilly for whoever happened to be at an intersection first! which we all know they do not. No matter HOW heavy or light you ride is.

[rachel]

Many left-turn arrows only trigger if there is a car detected in the turn lane. Similarly, lights where a small road crosses a large one may leave the green on the major road until there is a car waiting on the small road. I have this problem often on a motorcycle, I'll probably use this elegant trick.

[Kipkay]

Great! Come back and tell us how well it worked...

[marc92]

I think the emergency vehicles have sirens and lights and laws to say "Get your ass out of my way! I'm going through a red light and there is nothing you can do about it!" But the infared system may help.

[ravenprints]

there was a problem with people selling(ebay etc.) the infrared triggering systems about a year ago. On the news etc. Seems many major intersections have a small pillar type reciever that special lights can trigger. E-vehicles are the ones only supposed to have them. But it is easy tech to copy. Hence the problem with others triggering light changes to serve themselves. sirens andlights yes, but don't expect the police etc to ignore ANY way that will help them get through. I was standing on a street corner in denver CO once and happened to see a traffic light change from green to red! NO yellow. Lady slammed on her brakes and three cars ended up in that crash. She was SO upset and I was glad that I was there to back up what happened. I now wonder if somebody(coming from one side or the other?)tripped that light in such a way??? Any way, it could easily end up just like what I saw if unauthorised and selfish drivers get and use this type of light. I used to ride a motorcycle in AZ and I found that if I stopped right over one of the wires instead of between and revved a bit, this would be no problem.

[Derin]

hah funny in istanbul/turkey it lights yellow when going to red but not when vice-versa!

[marc92]

typical American: take a technology that helps the community and hog it for themselves.

[ravenprints]

At least WE are free and smart enough to do it!

[Austringer]

Well, except in Boston. (Realistically I think the line of conversation pretty counterproductive, but that's how I feel about the, what now, third Boston bomb debacle?)

[cpf]

Yes, but should you?

[marc92]

my point exactly

[brian25]

This is a really asinine, useless comment.

[marc92]

it was a reply to ravenprints comment above, if you look at the indentations.

[brian25]

It still is asinine and useless. Your comment of "typical American" is condescending and useless. I don't know where you are from, but probably from the "great" nation of France - see I can use it too!

[marc92]

No, I'm an American poking fun at the people of my country. But, I've heard France is nice

[jdyahoo]

Move there. You might even meet Johnny Depp. Maybe you can ask all those Hollywood types who screamed long and loud about how they would move out of the country if Georgie porgy got elected why they're still here before you go. That guy's been elected twice and not one of them has left yet. Any they wonder why no one cared if they left in the first place.

[chuckr44]

It all makes sense. I wondered why I would see construction workers cutting a 1/2 wide slot in the road, and I'd come back later and all they did was fill it with tar. They must be installing wires for something like the traffic light.

[_soapy_]

That's exactly correct. I'd love to know why they don't just lay them down and tarmac over the wires, though! Just use a good wire with a fire-proof coating on it, and it would save a fortune.

[frollard]

in new installations they often do - BUT a lot of these loops need to be maintained/replaced. Tar is easier to remove than asphault.

[_soapy_]

Never seen them use anything but a diamond water-cooled disc for opening them up. But there you go! Not sure why the loops would ever fail, either, unless they aren't putting them deep enough. A foot of solid rock/tar should stop even a 44 ton truck.

[vbrtrmn]

If you live in an area with rapid climate changes, freezing and fast thawing could cause the wires to wear out, due to thermal expansion and contraction.

[_soapy_]

Pretty unlikely, earth is a very good insulator, and will limit the temperature rate of change very greatly. Even in the depths of winter, it is rare for the earth to freeze to great depth. Wires and the like are also far more flexible than the concrete and tar. Only if the wires were completely taut would it be an issue. And that would be a pretty daft way to install the wires!

[jridley]

You should check out the intersections on heavy truck routes around here. The asphalt actually gets seriously disturbed; I've seen "waves" in the asphalt where the trucks sit and then accelerate where they push the asphalt backwards; usually there's a bump up about 6 inches followed by a dip of 6 or more inches. On the offramps from the expressway, I've seen a series of bumps; basically the heavy trucks have managed to create a 6" washboard in the asphalt. Loops embedded in that asphalt don't last long. Eventually they usually give up and put down concrete within a couple hundred feet of such intersections.

[chuckr44]

IN regard to wires a few inches below ground level: I have to disagree with you here. I have lived in Michigan all my life. And I tried to dig in the dirt one winter. The sand was frozen to 12 inches. Local codes require that all footings and poles (like for fences, light poles) and underground wiring be 3 feet deep. Wiring must also be encased in waterproof pipes. It's the movement of the ground that scrapes against wire insulation, causing holes. Ice crystals are pretty hard. Ask anyone who has fallen on their face in the ice. Their bloody face tells a clear story. Also, the plastic insulator on the wire degrades in the cooling and heating of the seasons. It takes years, but it does happen. Thus the wires in the road are covered with tar, which expands and contracts with the seasons. The tar eventually needs replacing about every 2-3 years. I can see the results in my local parking lots with lots of cracked tar which was used to patch cracks in asphalt. In regard to caves: yes, the stone and earth makes a good insulator. Caves are typically 60F-65F degrees year round.

[jridley]

That's to say nothing of the fact that here in Michigan, the frost heave literally tears the roads apart. You can look at parking lots that have not been used in 10 years and they're falling apart; roads that actually get traffic (though they usually have better beds than parking lots) take a lot more abuse.

[Kitsune818]

This is *not* some miraculous way to turn a light green. What the author is describing is a method for getting the lights to know you are there. Sometimes, on a motorcycle or in a small car like my old Metro, the light never senses you, so it never turns green for you and you sit at the red light forever. With this, you still have to wait through the light..but it least the lights know you are there to give you your turn.

[ravenprints]

MUCH better said! I have been at such lights too. Even in a big old chevy van! ad and video make it sound like a couple of magnets will turn the lights green just to make you happy! It does not make clear what YOU just and so easily said.

[brian25]

The loops in the ground can be cut into the pavement or placed in PVC pipe in a recess in the ground and then pavement is poured over them. The wires are fed back to a loop detector. The wires are not loop detector's in of themselves. You need a loop detector to measure the difference in magnetic inductance. The loop detector can be adjusted for sensitivity. Also, the reason they use that pattern is because it is the best for detecting vehicles of all types. In parking garage entrance and exit lanes, they use either two loop close, two loop far, or three loop configuration for what is known as loop logic. The loop logic is handled by a PLC or some other controller. Traffic lights have similar controllers.

[Metal4God]

thats false we sometimes wait 5 min. in traffic lights and we own a yukonXL (three quater ton) im iving this a minus 1!

[Alan the Great]

Fender: Wow. It's people like you that make me lose faith in humanity. Just because something doesn't work for you personally doesn't mean you should assume it's a fake and leave negative feedback. I usually don't vote, but I'll go +1 to cancel out that asshat.

[Knexagon]

Alan the Great. Wow. It's people like you who make me want to kill myself. Just because everyone has opinions doesn't mean you should stuff yours down other people's throats. I sometimes vote, so I'll take your +1 and cancel it out with my -1.

[trebuchet03]

{because everyone else is doing it}

make me want to kill myself.
People like you make me happy that the Baker Act exists :p

I cancel your -1 with a +1, and raise you a checked feature box (which, happens to already be done) :p

In any case, Alan is right - and it really wasn't opinion. Because something doesn't work for you is not necessarily an indication that the claim is false. It's pretty much like you getting an answer of 5 on a math question while the rest of the class got 10 (what are the odds everyone else is wrong) :p

[Wolf Seril]

Well if you had even read the instructable you would have seen its about magnetic feilds, not weight. Anyway its probably karma biting you in the ass for owning an SUV

[trebuchet03]

5 minutes isn't bad when compared to... it never turns green :p It doesn't mean an instant green - the switches are just for logic. How the traffic light uses the switches will vary ;)

[The_Harbinger]

In the plat where I live (state of Ohio), there are three exits for the entire neighborhood. One of them has a traffic light. About five years ago, before they resurfaced the road, I noticed where the inductive loop was placed on that road...about three car lengths back from the white 'stop here' line. I then observed that it took approximately three 'trips' over that sensor before the light changed more quickly. If you were the only car to travel over that loop, the light wouldn't change early. I also noticed after a while that, since cars could right-turn on red, that often three 'trips' wouldn't necessarily cause the light to change faster. So, what I do is: drive over the loop once; back up past the loop, then pull forward until I'm sitting over the loop, about three car-lengths back. If I see a car coming up behind me, I pull up about 1 car length (so they're sitting over the loop), and if I see two cars I just pull on up to the 'stop here' line. I get strange looks from people turning onto the street (go figure), but I can reliably make the light change faster by doing this.

[Sitnalta]

You say this is a "scientific" way of solving the problem, but there isn't actually any science is there? You just stuck a magnet on the bottom of your scooter and hoped that it works. In fact, you haven't even showed us any evidence that this works at all. All of the evidence I've found so far says that magnets have no effect whatsoever on these loop detectors. They (engineers who design these systems) say that positioning the bike/scooter wheel over one corner of the loop is the only real way to trip them.

[Knexagon]

I agree, for all we know he could have waited till the light changed and cut out the rest of him waiting in the video.

[rroseselavy]

Is there a reason for using 2 magnets, or can I just use one with a pulling force of 12lbs or more? And is the magnitude of pulling force related to the speed of traffic light change at all?

[Sidney Floyd]

am i the only one who finds the narration to these videos really annoying?

[Kipkay]

No...I do too.

[btop]

I do, always the same voice.

[Kipkay]

Yea...wish I could change my voice to sound like Don Lafontaine...

[Digital_Anarchy]

I always thought you did the cheesy advert style voice on purpose. you really should get a job advertising for TV.

[Sgt.Waffles]

Or Ricardo Montobaun. That would be hot.

[CowGuy]

How does your voice sound the same in videos all the time? I mean I swear it's computer generated or something, ALWAYS THE SAME EVERY DAMN TIME!

[Kipkay]

LOL! When you talk do you sound different every time or the same? I can do character voices. Maybe the next one I will do will sound like Bugs Bunny.

[BenH]

Well, your's aren't near as bad as shootingeggs' videos. My God, where does he get such horrible sounding music?!

[Kipkay]

"Aren't near as bad"? Not sure if that's a compliment or not but thanks...

[BenH]

They aren't bad at all, just any one who dislikes your videos should see shootingeggs'. Your voice is fine.

[Kipkay]

LOL! I was only kidding with you. Thanks!

[BenH]

Oh! You're welcome. It's hard to tell on the internet.

[Sgt.Waffles]

Porky Pig please.

[ArtisticBabe]

I was explaining the science of this to my mom in her car and trying to persuade her to let me do it to hers (on mine, its like magic!) and she was so bored! She actually tuned out.....poor non-science brained mom. :)

[!Andrew_Modder!]

oh, so basicly it changes the frequency or somthing lol, that small vehicles dont have so to speak (they dont really have a frequency just yea) but it tripps the light to change, basicly mimics the 'zone' of a larger car? so it would NOT be useful no um a mini-van :-P? oh yeah, kip kay your my favorite instructable'r lol :-) all your stuff is GREAT, clear, and freakin cool lol!

[sk8terhippy]

hay dude how did u get a picture of meatwodd in front of your name when you make a comment

[!Andrew_Modder!]

lol rly? u must b a instructanoob :-P ok go here http://www.instructables.com/account/settings?modify=IMAGES when your logged in, and then hit upload pics, and put what ever :-)............... ( . ) ( . ) yay that was random

[deusnoctum]

No, it works on the principle of inductance. A current is sent through the metal wire in the ground, which creates a magnetic field, and (basically) when a large enough metal object gets close to it, it changed the magnetic field and thus the current in the coil. The traffic system can then detect when a car has passed over it by the change in current. In this case, the magnet, rather than a large mass of metal, is changing the coil's magnetic field. Because magnetic field strength falls off as the inverse square of distance, the closer you can get it to the ground (i.e., the coil) the better. This should then work on anything--bikes, shoes, strollers, pets, motorcycles, basketballs, whatever.

[jaime9999]

"When a vehicle passes over the loop or is stopped within the loop, the vehicle induces eddy currents in the wire loops, which decrease their inductance."

From the FHA's comprensive description of the theory of Loop Operation.

Note that commercial devices like this exist for bicycles and motorcycles.

[!Andrew_Modder!]

..................................................thats what i meant........... :-|

[sanity]

I would have thought it worked like a metal detector had two coils, one which is supplied with a constant alternating field (b-field) and a second coil that can detect the resonating magnetic field of a metallic object effected by the first coil. If this were the case, a magnet would probably make very little (if no) difference in the resonance of a b-coil detection loop. Probably as much resonant variation as a small piece of metal would to a metal detector.... shrug....

[wiml]

I'm pretty sure there are two different inductive-loop designs out there for traffic lights. One acts like a metal detector, like you say, and a having a magnet on your car makes no difference. The other kind acts like a magnetometer --- detects the change in static magnetic field caused by having a big ferrous object nearby; they were used to detect submarines in ww2, for example --- and for a magnetometer, hanging a magnet on your car would make a big difference. FWIW, the loops are intended to be sensitive enough to detect scooters and bicycles. In theory, you should be able to ask your city's road maintenance dept to come out and check that a given loop is working right and is sensitive enough. They'll also paint a little "T"-shaped mark on the road where you should put your front tire for best results.

[NullLifeException]

I hate to sound like I haven't fully understood the science behind this, but... if this sensor is producing an electromagnetic field in order to detect the change when a large conducting body is nearby, you should be able to detect the presence of such a sensor in the road by using a similar magnetometer, right? Is such an instrument a complicated device? Is there an instructable for one?

[sk8terhippy]

wow thats a good idea

[ackackack]

works great, thanks

[JamesRPatrick]

I would put a grain of rice in the tube when you close it just in case there is any moisture.

[Kipkay]

Not a bad idea. Those Bison tubes stay dry. We use them all the time for geocaching

[Tierra]

Awesome, I ride my bike everywhere and this would be sweet to use to not get all stuck at the lights waiting for a car to come and save me.

[APSBiker]

And one even easier and free way to do it with your bike too - just put your wheels directly on top of the center section of the loop in your direction of travel. Works 99% of the time for a 2-wheel vehicle.

[gnose]

hmm..i tried it in the city and it didnt work, but it worked in lights that are less crowded and not constantly used. turns out the frequently used lights just use a system of timers..

[trebuchet03]

Some systems will use a combination of timers and switch feedback... The lights I cross on my bike commute are like that. They are on a timer, but they will only run their left turn "program" if the ground loop detects a vehicle.

[jedB]

Did you mean across the direction of travel?

[Kipkay]

Perpendicular to the road as you ride on it, yes.

[Ayce]

Thank you for the instructable I'll have to try this. And thank you bugman1470 until I get some magnets I'll have to try what you mentioned.

[bicyclelifestyle]

Is this the same principle as drive-thru sensors? I want to put the magnets on my bicycle and go thru a drive-thru. Would it work?

[Quazwrath]

No, it wouldn't. I tried this. It's a motion sensor. My bike was moving back and forth a couple inches because my brakes were worn down so it kept showing up to them as if there were a new person there every second or two and while I was talking the would cut me off and say "Welcome to McDonald's," even though they could hear me talking...

[Skamandrios]

I just look for the "cut" in the pavement where the sensor is and touch it with my side kickstand. Works every time. You might have to put the bike in neutral though; some models kill the engine when the bike is in gear and you put the stand down. Admittedly a little more trouble than a magnet, but it's an option when you need it.

[random43]

This is a nice little invention, and I would imagine that it works as advertised. However, the reality is that many cities are moving away from inductive loops and switching over to video and radar detection anyway.

[douro20]

These things ought to be as illegal as unauthorized Opticom triggers. People caught with an unauthorized Opticom can be prosecuted as terrorists under a new law.

[trebuchet03]

Haha, thanks for the bedtime laugh :P

Optical triggers give someone an advantage (3m's opticom can be setup to trigger a 4 way red light - not too uncommon where it's used). Triggering the floor sensor when as you stop at a red light gives no one a disadvantage. Just FYI - you don't need a magnet to create a magnetic field ;)

If increasing your magnetic field is illegal -- it should be illegal to transport any metal in your car.. Hell, it should be illegal to make cars from metal :p The more you've got, the easier it will be for your to induce a current through the inductor :p

Here's some reading to further your understanding....

Inductance
Magnetic Flux
Magnetic Flux Density

Thanks for the laugh though -- I can sleep better now knowing we're all terrorists :)

[ROCKETMAN]

There is nothing illegal about increasing a vehicle's presence. I have assisted traffic signal tecs over the last 25 yrs and one of the tec's bigest complaints is drivers who fail to stop over top of the loop. If a car stops past the loop usualy past the stop bar the loop may not register the car's presence when it passed over the loop. That can mean a 10 minute wait untill someone stops in back of you on a quite street late at night. That prompts a call to the local police that the light isn't working. Meaning someone has to go out at 2am to fix a problem that doesn't exist.(No-one realy wants that kind of over-time pay. To much lost sleep for nothing.) What would be illegal is anything that would tamper with the way a signal's timing plan functions.

[Truik]

Well, if using a MAGNET to get the same effect as a larger vehicle (greater thatn 90% of the other vehicles on the road) is a crime, then someone ought to go ahead and start a class-action lawsuit against every city that uses the induction loops because they would be biased against smaller vehicles and are treating them unfairly...ya know...as long as we are talking nonsense.

[Kipkay]

What? They aren;t doing anything illegal! Just compensating for loops that don't see enough metal or loops that have been buried deeper due to road repairs...

[wiml]

When I first saw the title of this instructible I thought it was going to be a lame (and illegal) "chrome box" Opticom thing also, I was pleased to discover it wasn't.

[pagangod]

nice video, but where i live we don't have thoes thing in the road, instead all of our lights are on a timer, do you know how to speed up the timer?

[ROCKETMAN]

If the signals in your area still run on fixed time then you can't legaly do anything on your own to change the timing. Be sides think of all the confusion if just 1% of drivers could control signal times to their personal advantage. Traffic tie-ups would only get worse.

[instructa-fan]

we got cameras. if it sees no cars with a certain amount of distance two opposite directions it will let traffic go the other two ways.......

[CowGuy]

I wonder if this is violating some kind of traffic law.

[Kipkay]

You don't need to wonder anylonger because they are not doing anything wrong other than triggering the detector like a large car would.

[furcino]

ROFL for half an hour, I also liked the other stuff you made. IR googles XD

[Sneaky Chopsticks]

Hmmm I'll try that later on

[ToneyR]

That is really cool! I would like to get one of those gizmos that the firetrucks use to make the light green while they are responding to a fire.

[rocketbat]

you didnt hear this from me, but you can do it with a universal remote with the right code. oops! i accidentaly fell on my keyboard and made an arrangement of ranodom letters!

[medic319]

Take it from me (a firefighter), our system works off of he "Yelp" tome on our siren. Kind of hard to be stealth with a 200 watt siren blaring. There are some systems that work off of IR light from strobes. These systems recognize a certain pattern (two, three, four flashes etc.). So in this case, it would be possible to drive around with a strobe light with a IR filter (to filter all but the IR light out) set to flash at the right pattern, and your lights would change. Just don't tell anybody you heard it here.

Steve
Shamrock Gear and Repair

[Kipkay]

No that's a hoax. Can't be done with a remote.

[Kipkay]

No you don't. You will get busted for using one of those and they run about $500.

[ToneyR]

Is there some technology built in to the system that can detect being hacked and can locate the source of the hack?

[Kipkay]

No. It's not really being 'hacked'. All you are doing is simulating what a large amount of metal would do and causing it to trigger the way it should.

[WannaBeDuck]

even tho i dont have a driver license thats so cool how u can avoid traffic lights!!!!!!! SICK LOL!!!

[The New Nexus 8]

Nice. Glad someone posted this, although the guy in the back pages of motorcycle zines might not like reduced sales of his trigger. My thought: How about placing inside of riding boot?

[Kipkay]

What guy? What trigger?

[wingbatwu]

At night, when there's no one around, I like to epoxy magnets on the asphalt on top of those loops.

[jkimball]

I used to work in a place that had a garage door that was controlled in a similar fashion. We used a length of pipe laid along the edge of the sensor to do the same thing. As I understand it, the metal pipe "concentrates" the magnetic field, making it seem like a larger metal object is there. It isn't as portable as a powerful magnet, but it is often much more common.

[secant]

You have to have a really strong magnet ... I have been using magnets form Signal Sorcerer on three motorcycles and three bicycles for 4 years. It works everytime!!! www.signalsorcerer.com

[Kipkay]

Thanks for the info and the testimonial.

[zm634]

Another great one Kipkay! My dad actually modified his route because his bike won't set off traffic lights.

[fegundez1]

I have used old hd magnets to do this so long as they are close enough to the sensors they will work.sometimes you have to move around a bit to trigger but it does work

[tiuk]

That's pretty cool. Amazing that such a small magnet can make the difference, no matter how powerful.

[dbarak]

I'm going to mount some magnets to the front of my truck with a quarter mile long pole. I'll never have to deal with a red light again... : )

[miniopa1]

Is that how all of them are because I know around here if you are in a motorcycle or moped all you have to do is stay in the right or left side or the lane at a light for it to change and it works on a regular bicycle too.?