Instructables
Bike thieves suck, so I decided to get even. Why not track and, if you'd like, shock these most egregious of folk?

With a $40 pay-as-you-go cell phone, stun gun, and some basic electronic components, you can teach bike thieves a lesson and, hopefully, foster a small social change through individual action:)

Shameless self-promotion: I've got this and my other stuff for sale here

Updated: here's me demoing this at Dorkbot Austin last month. And yes, I shock myself:)


Here's the original video of me explaining details on building this:

 
Remove these adsRemove these ads by Signing Up

Step 1: Ingredients

Part of what will make this secure is variance in the approaches we take. Feel free to start with a system similar to mine, but be sure to vary it up!

For a basic system that shocks and tracks, here's what you'll need:
-stun gun; I used the basic, ~50,000 volt one I found at a local sporting goods store. ~$20. You could also mod an instant camera or build one from scratch...
-Phone capable of talking to some tracking system. I went with mologogo, but feel free to play around with others. For the boost mobile motorola i425t, I paid ~$40. Unlimited internet service is like 35 cents a day. I haven't tried, but I've heard reports of being able to use mologogo without buying the net service...
-a diode to connect in paralel with the stun gun, because we're obviously concerned about safety...
-assorted thin-gauge interconnecting wires and non conductive electrical tapes
-circuit protobyping board
-a basic npn transistor, with datasheet. i used the 2n5088.
-a resistor sized based on your transistor. i used a 1.5-ohm one
To choose the right transistor and resistor, read this guide and look at these circuits. If you're using this same design as I did, the load you're trying to control is the 9v battery connection to the stun gun at 9volts 2.8 amps. If you go off the vibrating motor, you're controlling this via something like ~5volts .5 amps...

Useful tools were:
-screwdriver for the weird screws in the back of the cell phone. it was like ultra-tiny torx or something; your best bet is to get the phone, try your existing collection of weird screwdrivers, and get a specific new one if you need to
-utility blade
-multimeter (with ammeter)
-wire stripper
-soldering iron, solder
-'helping hands' alligator clip + magnifying glass thing
1-40 of 238Next »
Leprae15 days ago

I know (several years ago,anyway) the capacitor in a dollar store 35mm flash camera could often hold enough power to kill humans so WORK SMART if you mod one!
To virtually eliminate the chance of offing a bike thief I'd base the
shock part on a TENS or similar unit. If you make a high voltage
deterrent you'll probably regret it,I know from personal experience in
my youth that an electric horse fence feels vastly different on dry
ground,in rain and if you're standing in water

Leprae15 days ago

I know (several years ago,anyway) the capacitor in a dollar store 35mm flash camera could often hold enough power to kill humans so WORK SMART if you mod one!
To virtually eliminate the chance of offing a bike thief I'd base the
shock part on a TENS or similar unit. If you make a high voltage
deterrent you'll probably regret it,I know from personal experience in
my youth that an electric horse fence feels vastly different on dry
ground,in rain and if you're standing in water

Leprae15 days ago

I know (several years ago,anyway) the capacitor in a dollar store 35mm flash camera could often hold enough power to kill humans so WORK SMART if you mod one! To virtually eliminate the chance of offing a bike thief I'd base the shock part on a TENS or similar unit. If you make a high voltage deterrent you'll probably regret it,I know from personal experience in my youth that an electric horse fence feels vastly different on dry ground,in rain and if you're standing in water

Leprae15 days ago

I know (several years ago,anyway) the capacitor in a dollar store 35mm flash camera could often hold enough power to kill humans so WORK SMART if you mod one! To virtually eliminate the chance of offing a bike thief I'd base the shock part on a TENS or similar unit. If you make a high voltage deterrent you'll probably regret it,I know from personal experience in my youth that an electric horse fence feels vastly different on dry ground,in rain and if you're standing in water

spylock1 year ago
You wanna catch a thief in your community,get a bike that you dont mind getting ripped off,and get some stuff we use in plumbing called Blue Block.Smear the stuff on the underside of the grips,or somewhere that its sure to get on the thiefs skin,it will not come off,I know of nothing that will get that blue block off,it takes about a week or so to wear off.So the old bike gets ripped off,but you see someone walking around with blue stuff on their hands,and you got your thief.
Brett_cgb6 years ago
It's not a good idea to pass electric current through the chest cavity - this can stop the heart with a very low current (voltage does not matter). The idea of placing both electrodes close together makes sense. This is how the stun gun originally works. Allowing the electrodes to arc will prevent electrical transients elsewhere is the system, though that is likely not a problem here. Consider placing thumbtacks in the seat (exposed disks), one for each butt cheek. This ensures a good contact, and would probably incapacitate a riders legs if/when the stun gun fires, further ensuring good contact.....
Or moving them up several inches to that balls area.......
Yeah except the last time my bike was stolen, the thief didn't have a "balls area". She sure knew how to cry when I found my bike in front of her work and she had to explain her boss why some stranger was taking her bike home.
finton rossta2 years ago
Sweet! I wish I could have been there. *&%^@% thieves. I'm with OliveGreenCarbine in thinking that a thief loses their rights during and after the event - not that I'd want them to die, but I'm less than concerned about any injuries they may sustain during the theft.
Good idea. One contact in the front (beak part) of the seat, one contact near the rear. Definitely nonfatal, definitely painful as hell.
I have a question, then: How safe are actual tasers? My understanding of a taser is that two probes are fired from the taser, and for maximum effect you want one probe to enter the lower body and one to enter the torso. Then, a current is passed between the two probes, and consequently the body. Because electricity follows the path of least resistance, the current should essentially pass straight through a leg and the torso from one probe to the other, correct? Doesn't this pass a significant amount of electric current through the chest cavity?
How safe are actual tasers?

http://en.wikipedia.org/wiki/Robert_Dzieka%C5%84ski_Taser_incident

And these guys were trained professionals.
Voltage does matter - it matters because without a high enough voltage you won't get any current flowing through the body/under the skin. 30V is about the minimum you'd need to get under the skin, and once you're through the skin, resistance is very low...
Both of you are wrong, but at the same time right. I've been using electronics and studying electronics for years. It's amps that can kill you. In fact, it's really all 3. Amps, current, and volts. For amps, it's only 6 milliamps through the heart to kill you. That's a very small amount, yet it's still leathal.
all 3? amps is current. the third component is resistance.
Yes; it's the current that kill you, but in order to deliver that current to the heart you need enough voltage (i.e. pressure) to get through the skin.
Don't even try and argue with me. I've been with this stuff for all my life, and it's not volts already. Get over it. Your wrong. 30V psh. You can actually have a double A battery kill you if you get shocked in the right place.It's all about current....not volts.
Maybe there are others in the world who have been studying and using electronics for years? Yes, a AA battery can kill you, if you connect wires to the end of it and stick those wires through the skin and into the flesh either side of a person's heart. But that's not the point - humans have a useful barrier to (among other things) electricity. It's called the skin. It has a high resistance (put an ohmmeter on your skin to try it) , meaning that in order to deliver a current dangerous enough to kill, you need a high voltage. V=IR. Once you're under the skin, all bets are off. But that doesn't really happen. As Brett_cgb said, 30V is what they use in hospitals. Because it's safe enough not to get through the skin in the worst case scenario (short of having an exposed heart and some bare wire lying around). Without voltage there is no current (water analogy: without pressure there is no flow).

And perhaps be a bit friendlier too...
Let's end this. A 1.5V cell cannot kill you unless applied directly to the heart, something nobody is able to do. In the end it's current that kills. The voltage required is dependent upon method of delivery. And above, the skin effect was mentioned... Here's proof that it's the method of delivery: Many people have been killed by lightning strikes. We're talking millions of volts AND millions of amps. However, many have survived as well. Why? Skin effect, and other paths external to the heart. Blown eardrums is a common side effect. But that could be simply due to the "explosion" shockwave when it hits you. There's also a pretty famous video of a soccer field and lightning hits the corner of the field directly to earth. Everyone on the field collapses. I think everyone survived. So, in that case, though there was no direct conduction across the heart, there was enough total body conduction to cause muscle contraction and/or temporary unconsciousness. I think this topic has been beaten to death... (No pun intended! heheh)
OK although everything you say is true, there are two things that you're not considering: 1. Although the stun gun can't kill you, it's possible (although very unlikely) that the thief has cuts on both his hands, allowing the current to pass through his heart. I realise this is really unlikely, but I wouldn't want to risk the knowledge that I killed someone, especially if it was just a young teenager... 2. Without passing through the heart, a 1.5 V cell can't kill you directly. But if I was riding along a busy highway on a bike, 1.5V could easily cause me to lose control of the bike and crash. That could kill someone easily. I really like the principle of the idea, but it needs to be thought through more thoroughly for it to work.
Yeah, a LOT of thought not to mention the involved engineering as well as legal issues. That said, I ran ideas through my head on how to electrify my 98 Cobra when new. Since a car is inherently insulated from earth ground, it would not take more than a battery powered DC-DC converter, and a small conductive wire touching the ground. You could charge the chassis up to tens of kV easily. The kewl thing is that due to the sheer mass involved, the thief would get one hell of a short, but pAINFUL ZAP. Like a giant door in the winter. Heck, my own car zaps me after a trip when getting out and you touch the door. Shows how a charge can build up and remain there quite awhile and still shock you. Wet weather though would pretty much "discharge" the car's charge. But in any event, it is doubtful it would cause any injury. You'd also need some sort of warning system letting him know, back off now or the car will strike back! :)) Gee reminds me of KITT! The insulation of the tires is also why if your in a bad lightning storm, stay in the car! And don't touch anything to avoid any possible side paths through you. You want to electrify a bike... same principles of tire insulation and only a tiny HV power supply A few mA to zap them no more dangerously than an electric fence used on farms. Can you grab it? Sure. Is it gonna hurt? yeah. Will it klll you.... No. The huge difference is a stun gun pumping out continuous current vs. a very short, high voltage spike. Works for livestock! lol It may sound like I'm contradicting myself, but not at all. There's no path through the chest cavity, just your hand to Earth ground... something we all experience during dry winter seasons. Makes your blankets have lightning storms in them too!
He's right people. It doesn't matter HOW the current raches your heart's pacemaker, and OK, a 1.5V battery might be tough to shove curent into you, and yeah, you can lick a 9V battery to check it's charge and it won't hurt you (I do it al the time), just spaz your tongue out, but if your tongue can convulse at 9V, you can see, it might not take much voltage to generate the current. I have to agree with "ask", the voltage required varied depending on skin conductivity which varies widely... i.e. dry, wet, salty, etc.
ac1D askvictor6 years ago
i dont think so. the skin is in direct contact with blood and all, no?
I'll second that!
Taken from <a rel="nofollow" href="http://en.wikipedia.org/wiki/Electric_shock#Lethality_of_a_shock">Wikipedia</a><br/><br/>It is sometimes suggested that human lethality is most common with alternating current at 100–250 volts, however death has occurred from supplies as low as 32 volts and supplies at over 250 volts frequently cause fatalities. The voltage necessary for electrocution depends on the current flowing through the body and the duration of the current flow.<br/>
Amps (or amperes) is a unit of electrical current.
amps are the UNIT for current
Granted, voltage does matter, but not as much as you think. 30mA (0.03A) through the heart WILL stop it (less current will still affect the hearts operation, possibly lethal). The voltage required to drive that current depends on the body’s resistance, which changes depending on what the body is doing. If the body is exercising (as it likely would be on a bike), the resistance will be low due to sweat (among other things), allowing higher currents.

30V is the maximum voltage that can be applied under worst case conditions (sweating, standing knee deep in salt water) and not reach 30mA. This is the standard for hospital grade electrical equipment (that's what that green dot on some plugs and electrical outputs signifies).

- - - -

The stun gun is likely not lethal in its original configuration (electrodes less than 1 inch (2.5cm) apart) so there's little chance of driving a significant current through more than a few inches of skin, but increase the spacing and all bets are off.

F.Y.I.

Amps = ampere = current
Volt = voltage
Ohm = resistance

Amp = Volt / Ohm

- - - -

It’s hot, but it's a dry heat.......
So...what are watts?
In terms of DC (direct current, which a stun gun does NOT produce)
Watts ( W, a unit of power) = V * A (Volt * Amp)

- - - -

AC terms (alternating current):

For resistive loads (incandescent lamp or heater), the same equation still works.

With reactive loads (motors), things are more complicated as the voltage and current are not in phase - they do not measure zero at the same time. Current usually lags behind the voltage (assumes voltage and current are both sine waves). Additional terms needed for this discussion include frequency, phase angle, true power, apparent power, reactive power, power factor, and complex impedance.

With harmonic loads (fluorescent lamps, most electronics, and lamp dimmers), current is either in phase with voltage, or is zero (current is not a sine wave, may be a pulse during each half cycle). Additional terms for this discussion include frequency, harmonic distortion, and crest factor.

More than you wanted to know?

- - - -

For purposes of the stun gun, we can assume a resistive load across the electrodes.
And yes, I am an engineer.
So basically, it exists in DC as V*A, but not really in AC. That helped, thanks.
in ac, v*a*pf=watts
pf = power factor.

power factor is only important to the utility company, not the end user.
Brett, Couple of minor points. When Current and Voltage are out of phase (as you correctly point out in your inductive motor example) they can (and sometimes it is desirable) be at zero at the same time, if the phase shift is 180 degrees. Harmonic loads do not affect power at all, and are not relevant to this discussion. The current neither lags nor precedes voltage when out of phase. It's just out of phase. It is simply a convention to assume the current is behind the voltage (15degrees behind... it's the same thing as 165degrees ahead.) Complex impedance is not related to this discussion. Impedance itself is implied when you refer to reactive loads. Fluorescent lamps are not harmonic loads. The ballasts that drive them are. Current may not be a sine wave, but it MUST be a wave, and can never be a pulse. If current is zero, there is no voltage. (did you think this through?) Harmonic distortion does absolutely not apply to any power discussion. Crest factor is only a factor when you are rectifying AC. Fairly good display of power and control knowledge. Shame it's not germane to the subject. There's tons more I'd like to know, but I seriously doubt you'd be the one to school me. Nice dick flopping though.
> When Current and Voltage are out of phase (as you correctly point out in > your inductive motor example) they can (and sometimes it is desirable) > be at zero at the same time, if the phase shift is 180 degrees. If the phase shift is 180 degrees (lead and lag are essentially the same thing) then you have a generator rather than a motor if work is being done (there is a loss of energy in the system), or a resonant circuit (no losses). > (15degrees behind... it's the same thing as 165degrees ahead.) That's 345 degrees ahead... Running the calculations with 345 degrees ahead will give the same results as 15 degrees behind, but it's slightly more convenient (and easier to grasp) to restrict the range of angles to within a +/-180 degree range. In the real world, current pulses occur all over the place though they are not perfect rectangular pulses. Those devices sitting in front of you (computer and monitor) both use switching power supplies that use pulses of current to perform power conversions. It is not necessary to have a voltage in order to have a current. It is necessary to have a voltage to AFFECT a current (increase, decrease, change its direction of motion). > If current is zero, there is no voltage. (did you think this through?) Apparently more than you did.... How do you explain charged capacitors? A resonant half wave antenna? Antennas are an excellent place to observe points with 0 voltage/peak current AND peak voltage/0 current in a single piece of wire at the same time. Ever hear of standing waves? > Crest factor is only a factor when you are rectifying AC. Ever read the specifications for multimeters? Most meters are calibrated to measure an average value, but display it as an RMS value. When the waveform is a sine wave (or something close) everything is assumed to be correct. But if the waveform deviates from a sine wave, then RMS and Averaging meters will show different results. A DC-AC inverter with a "modified sine-wave" output is a good signal source. Check it out. I think you know enough to be dangerous....
amps * volts = watts
Brett, the green dot does indeed mean hospital grade, but has nothing to do with 30v/30,mA. Just means it went through a higher level of QA/QC.
Yes, it's only the current that matters.... Considering that nobody dies in the winter from a sometimes painful ZAP to the finger on a doorknob, or to your buddy's face or wherever which is 30,000V easily, and can be close to 100,000V on a good rug and shoe combination ;) , should confirm that. Though you are correct, current across the chest is the most dangerous and 30mA is more than enough to stop your heart.
Static shocks are high voltage, but very, very miniscule current, which is why they are not dangerous. As long as the current is low enough, you can safely expose yourself to a pretty much limitless voltage and not run into any problems due to something called the "skin effect". I have personally drawn arcs over an inch long (so exceeding 100,000 volts) directly to my fingertips with no ill effects from the top of a tesla coil, but only because I knew the current was so very low it wouldn't penetrate any of my squishy inside bits. I would certainly not do the same with the kind of debilitating current involved in a tazer or similar devices. I don't know the exact current that is coming out of this gun, but neither does the guy who's designing it. It is definitely NOT designed to be applied all the way across the chest, and I think there's a pretty good chance it would be lethal if he sets it up as described.
While voltage matters, what shocks is the current. Your figure of 30V is incorrect, as is your assumption that the resistance is lower below the skin. The minimum voltage needed to produce noticeable shock is 9.7 V @300uA (a total of 2.91 W.) Skin resistance is typically 1MOhm/cm, and it's affected by a whole host of variables, like moisture of the skin (or lack of) being the most critical. Stun guns typically operate at 3mA, and voltages vary from 50KV to 160Kv (powers from 15W to 480W). The current is dependent on the conductivity of the skin, the higher the resistance, the lower the current. Note that there are physiological reactions below the voltage threshold, and while they can be measured, they are not noticeable to the subject.
1-40 of 238Next »