Joule Thief Troubles

I have built several Joule Thieves as seen in this video. None of them worked. Is the schematic wrong? I am sure that I used all the right components, and I wound the transformers right... What could be the problem? Could it be the ferrite core? I used one from an old computer power supply. Any help would be appreciated.

Posted by 1up 10 years ago

LEGO Stormtrooper Joule thief mod

Onkelond over at Flickr came up with a great way to make your lego minifigs light up!link

Posted by Zorink 10 years ago

Joule Thief w/ 555 timer

Hello, I have a question about using a 555 timer with a joule thief. I'm trying to build a circuit for some solar powered bike lights but I have a couple of questions... 1. Am I correct in assuming that it's a bad idea to try to run a TLC555 timer chip from the output of the joule thief? Without a load, it seemed to be pumping out at almost 80 volts. 2. I tried building the circuit so that the two rechargeable 1.2V batteries would power the 555 directly, and then the output would sink and source two transistors alternately, which in turn would switch the LEDs alternately, using the output from the joule thief, which was also powered directly from the battery. That resulted in no LEDs lit and some very hot transistors... Bad idea. The TLC555 chip is supposed to run on a supply voltage of 2-18V, but when I tested it with the 2.4V coming from the batteries, it would source, but not sink... Is there any way to build this circuit so the 555 could blink 2 LEDs alternately while the LEDs are powered by the joule thief? The only alternative I can see that might work would be to power the joule thief from the output of the 555 and just blink all of the LEDs at the same time from the joule thief's output. Any help would be appreciated!

Posted by amklose 8 years ago

"Joule Thief" LED Night Light Kit is Now Shipping

Thank you so much for those who pre-ordered the kits! I have shipped all orders now, and the kits are in stock. New orders will be shipped within 2 days. To purchase, please go to Please see this post for the pricing and more: Thanks!

Posted by ledartist 6 years ago

Wave JT Kit - LED Chaser with Joule Thief - Sale

Wave JT is an LED chaser/Larson scanner/sequencer what runs with just one AA battery. Joule Thief circuit boosts the 1.5V (or less) from the battery to 5V to power the microcontroller and LEDs. The kits are available at $19. PCB alone is $7. *** Summer Sale Price *** > see the instructable > go to my website for purchase

Posted by ledartist 6 years ago

"Joule Thief" LED Night Light Kit & PCB

UPDATE: Everything is shipping now. My instructable is here: "Joule Thief" LED Night Light  Check out the new color changing Joule Thief! KIT Pricing is $10.50 for the kit. Kit 5 Pack Save by ordering 5 packs for $39! PCB Pricing is $4.50 for the PCB. Shipping is $5 for USA, $17 for the rest of the world. *** NOTE: The color of the PCB will be green instead of purple shown in some of the pictures. *** Payment To order, please go to my site - Click on "Add to cart" button and check out via PayPal. Please send messages or leave comments here if you have questions. Thanks!

Posted by ledartist 7 years ago

LED Artist kits now available at The Maker Shed!

Two of my kits: USB Blinky and Colour Night Joule Thief kits are now available at The Maker Shed ( USB Blinky @ Maker Shed: Colour Night Joule Thief @ Maker Shed: Please check them out!

Posted by ledartist 5 years ago

Colour Night Joule Thief kit & PCB

Please see the instructable for the details and video of this project. *** This is a color changing LED version of "Night Joule Thief". Pricing is exactly the same. *** Kit (includes PCB) Pricing is $10.50 for the kit. Shipping is $5 for USA, $17 for the rest of the world. A picture of full contents is shown below. Kit 5 Pack Save by ordering 5 packs for $39! Shipping is $5 for USA, $17 for the rest of the world. PCB only Pricing is $4.50 for the PCB. Shipping is $5 for USA, $17 for the rest of the world. Payment To order, please go to my blog page at You will find buttons to buy, and checkout via PayPal. Please send messages or leave comments here if you have questions. Thanks!

Posted by ledartist 6 years ago

Joule Thief in between Peltier/TEG and DC Motor?

As per the title I've got a Peltier cooler chip sandwiched between 2 heat sinks acting as a Thermoelectric generator (TEG) which when sat on my wood burning stove generates about .5V (which is a bit disappointing).  The idea was to cheaply recreate one of the EcoFans, so the plan was to connect the TEG to a low voltage DC motor.  The obvious issue is the low output from the TEG itself - I need to maximise the heat dissipation from the top heatsink to create the temperature difference, but even solving that I'm going to struggle to consistently get more the 1V from the TEG. Before I go to the hassle of sourcing and making a Joule Thief (like the 1up instructable) is there something fundamental I've missed that means either the TEG won't work with the JT, or a 1.5V - 3V DC motor won't work with the JT? Appreciate any help is establishing the feasibility of this idea, or suggestions to an alternative solution :-)

Posted by thankyousam 6 years ago

Joule robber - a better joule thief....

I had a look at some of our 'ibles for the famous Joule Thief circuit. While checking a few of the creations and checking their performance I noticed a massive flaw: Only LED's with very low power consumptions can be used. After some trial and error I was able to create a slightly modified version that not only lights white and blue 5mm LED's but also the very powerful Cree Led's - the later would require a suitable transistor to handle the load. I only used a salvaged BC556 transistor, so the LED starts working at around 0.5V, brightness is adjustable within certain limits to cater for the battery state. So instead of using a limited circuit that basically just doubles the input voltage with the focus of extreme low power consumption, my circuit is aimed on single cell battery lamps that might need more power. Using a very low voltage transistor with minimal losses would still provide a power source for batteries that are under 0.5V, while using a bigger transistor like Tip142 or 2N3055 and a modified transformer can drive a CFL lamp from two AA batteries, single cell if you don't mind a warm transistor. Biggest improvement however is that I don't use a toroid core, which makes winding so much easier :) I am not too good in drawing circuits and prefer the direct solder method for my prototypes but if there interest I would take the time to make some pics and draw a circuit for an Instructable. But with so many similar circuits already out there I wanted to get some feedback first.

Posted by Downunder35m 3 years ago

LED circuit on flashlights

I have over 2 months trying to understand the circuit that LED flashlights have  that last a lot, yhe Joule Thief is not the circuit, because the flashlight circuit is just a capacitor, a resistor and a transistor.

Posted by GeorgeElectronics 3 years ago

high capacity joule thief/dc-dc converter

I'm trying to make a dc-dc converter with the following characteristics: Output = 5V regulated at up to 30mA = 150mW Input 1V (or lower) from a slightly flat AAA. Assuming a pessimistic circuit efficiency of 50%, then the input current would need to be 150mW / 0.5 / 1v =  300mA which I think a AAA is capable of supplying. I'm using a variation of "led torch circuit 2" from, but I've replaced with the 1n4148 with a schottky diode and replaced the 2 LEDs and 29R resistor with a 5k6 and 1k resistor respectively; this should limit the output of the circuit to just under 5v. I have a 150R resistor to provide a 30mA load to the circuit. When the input is 2.4V, the output is 4.62V which is close enough to 5v for me.  But if I decrease the input voltage to 1.14V, then the output voltage falls to 2.7V which is not enough. I have tried half a dozen hand wound transformers with various turns ratios, wire thicknesses and shapes (slug and toroid) but am unable to achieve 5v out (at 30mA) from 1v in. Does anyone have any suggestions as to what to adjust, or perhaps a better circuit?

Posted by GrotBox 6 years ago

anyway increase voltage without using ac ?

Anyway to increase voltage using only dc input and using low voltage batteries (1.5 ~ 9 V ) ? and without making big or with loads of parts circuit ? ( I need simple circuit) any more taughts than joule thief ?

Posted by chosenone3 9 years ago

Ferrite Beads

I want to make one of those joule thiefs and I live in the USA. I don't know why I want to make it, I'd never need it/use it... BUT I MUST HAVE IT!!! I'm looking for tiny ferrite beads (toroidal shape) that are cheap (less than 10cents a piece). They CANNOT be leaded

Posted by guyfrom7up 10 years ago

LED Capacitor Issue?

Ok, so i have a non alterable power source of about .75 volts. I need it to power a 1.8v red led. I don't want to use the joule thief to accomplish I hook up a capacitor to store energy, then transfer it to the led? or how can i get the led to fully illuminate? THANKS!!

Posted by Joe426 10 years ago

Gravity Lamp Calculations

Http:// some people might recognize this little invention a while ago.  Well I recently wanted to make one after a freak snow storm rocked central pennsylvania (didn't have power for 2 days, it sucked balls).  But, after doing the math, his claims seem impossible.  Someone check the math for me: Facts of the Gravity lamp (with data in favor of the lamp_: output: 600 lumens weight falling: 50 pounds distance falling: 58 inches (in reality it's a bit shorter, but i'm just putting everything in favor) for ease of calculation and in favor of the lamp, assuming 100% efficiency. lasts for 4 hours calculations: 600 lumens = 7542 candellas = 7542000 mcd the highest efficient LEDs i could find output 120,000mcd at 20mA (0.02 amps) with a drop of 3.2 volts 7542000mcd/120000mcd = 63 LEDs 1 LED = 3.2 volts * 0.02 amps = 0.064 watts 63 LEDs = 4 watts 50 pounds = 22.68 kg on earth: the force of the weight is 22.68*9.8 = 222.264 newtons 58 inches = 1.47 meters 1 joule = 1 watt * 1 second = 1 newton * 1 meter 222.264 newtons * 1.47 meters = 326.73 joules 326.73 joules / 4 watts = 81 seconds, NOT 4 hours looking back at it, I think i messed up the calculations at earth's gravity, because that part is just totally wrong :P.  I'm not far enough into my physics class to know how to properly calculate that, could someone else?

Posted by guyfrom7up 8 years ago

Please Read, if you want a story ask, but i need an idea

I need something all kool looking to show off in town and take to Spokane for christmas, to show off to my dad's girlfriends family. i thought of a kool looking joule theif and am planning on it but mehbey something else too. i have a story to tell let me know if you want to hear it in exchange for a idea.

Posted by Yerboogieman 9 years ago

Help with solar "flame" for dragon yard art

Synopsis:  I'm a novice here.  I'm trying to make a small electric tea light candle work from a solar landscape light to put a "flame" into a crappy 12" metal dragon sculpture for some yard art. My quandary:  The solar light only runs off of one AA battery (1.2 - 1.5v).  It appears to be using a 0116 IC? (I know nothing about these) to act as the Joule Thief to power the white LED that I assume is running around 3v.  The tea light uses 4.5v (3 x 1.5v) and has a 47 Ohm resistor, a capacitor, and a chip to control the "flicker" of the light. The Help:  Can anyone offer up some suggestions how I can properly get the flickering tea light to run from the 1AA  solar unit?  Could I do something like: 1. Remove white LED from solar light and check voltage 2. Replace resistor on tea light to accommodate voltage coming from Solar battery 3. Solder new wire from where the old white LED was on the solar light to the power leads on the tea light. Thanks for any thoughts, support, or reference.

Posted by csbeltram 6 years ago

Suggestions for what should be in my store

I will be opening an electronic kit store (and specialized cnc work, depending on what you want) and I'm just getting stuff prepared, such as PCB templates, etc. If you would like to see somthing in my store please suggest it now, everything will be very cheap, here are some of the things I'm working along with estimate price (I'll have a fixed one later, this is just what it'll be around). THESE WILL ALL BE KITS, LIST WILL BE UPDATED TO SHOW DIFFERENT PROGRESSES Custom PCB - 1 dollar initial, 50 cents per square inch Various breadboard mini power supplies - 1 to 2 dollars, somewhere around there 5 VOLT POWER SUPPLY DESIGN IS DONE WORKING ON VARIABLE, 3.3, 12 Dream Machine - Induces Lucid Dreaming by flashing LEDs through your eyelid throughout the night to help you realize your dreaming without waking up. $3 1/2 DONE CR2032 batteries - like 50 cents a piece, some of my uController kits use these DONE Joule Thief - Some people have trouble with this, so here's a kit ~1 dollar Dip Converter - like 50 cents, solder on SMD IC's so that you can use it with DIP sockets and/or breadboards Pulse LED Musik - I did have an instructable on this, but I think it should be properly done, no definite price yet. MAYBE THINGS Mini Cnc machine, mill your own small (like 4"x4") board at home! 60-100 dollars Fm transmitter for MP3 players More universal TV-B-Gone clone kit (better for mods) Magnetic levitator, that's a big maybe Homebrew Ipod accesories Universal uController Programmer little bread board volt meter little breadboard amp meter BB jumper wire and templates for jumper wire So, any suggestions? CONSIDERED INSTRUCTIONS BY INSTRUCTBLONIANS... UHHH PEOPLE From Tech-King Cables and Cords and plugs Custom plexiglass etching/engraving Project Boxes (I might buy from a big supplier at a discount and pass on the savings! Or eventually make them) Soldering kit HAM products

Posted by guyfrom7up 10 years ago

My airsoft gun.

This is my airsoft gun, its a SAS12. it fires at 240fps (1 joule, the max power limit for ireland) and packs a hell of a punch! its very accurate up to about 50-75ft. i painted the top of the barrel, for better looks, and the notches on the ironsights white, for easier aiming. its magazine capacity is 30 rounds. it also featues a safety switch just behind the trigger. it only cost me €50! (€35 for the gun, €10 for the pellets and €5 for the speed loader (holds 100 pellets)) its a brilliant airsoft gun!

Posted by ~KGB~ 7 years ago

Using LiPo batteries in coil guns

Hello all, this is my first post! I have been theorizing for a while about coilguns, and have been doing calculations. here is how it goes: A single Lithium polymer battery can hold up to 3.3 Ah and discharge at about 30c (safely). We multiply 3.3Ah by 30c and get 99 A of continuous discharge. That’s a LOT of current, but, it is still not enough to fire a good projectile. So, I’m planning on having four of these hooked up in parallel to give out 396A. This is quite a bit of dangerous current, so my wiring will have to be gauge-perfect. The magnetic field that this produces is about 9.9 teslas, as  twice much as your average MRI machine. Yes, I’m utilizing a miniature MRI to shoot stuff. If you want to know how much force an MRI puts out, here is a great video to show you I am planning on having a 2,000 turn coil, with the average distance from the projectile being 1cm. The ammunition is going to be BB bullets, which means our cross-sectional area is at least 7.65*10-4m2. Using those numbers, the initial force on the BB is 3,015,030N. This is enough to lift up 25 semi-trucks. On paper, this seems magnificent. However, I’m accounting for about 2% efficiency, taken into account at this step, giving us 60,300N. This is still an enormous force to take to a .5g BB I’m implementing the Impulse to be .05s using standardized E = F * t,  this gives us 3,015 joules of energy. Huh. that’s way more than we should expect. Let’s take into account the 2% efficiency rating again, and we get a more realistic number: 60 joules. 60 joules is ridiculous for a BB pellet. We’ll use Ek = 1/2*m*V2 to solve for V. I got about 1,553 m/s. This is faster than most guns shoot regular bullets. I will be using a 2-stage setup, and will make sure to  use proper electrical equipment. My question to you is; How accurate are these calculations? if I build this thing, what can I excpect?

Posted by bjohnson45 4 years ago

RoBot Gets E-textiled. First Ever Interactive Bot on Fabric

Just thought some of you, may enjoy this.My little Tribute to I' know I'm going to get good use out of this shirt now. It has already proven itself as a valid power checking device. I may even mod it into a joule theif.Oh RoBot friend of mine, you'll follow me to the end of time. Your glowing light ye shall thus shed, upon my darkened task ahead.I hope you like it.RoBot Gets E-textiled.

Posted by Lftndbt 9 years ago

Capacitor-bank safety issues

Okay, so I'm going to be the wet-blanket old guy.... Has anyone considered adding a topic to this group (or an I'ble) on electrical safety with supercaps? Even the low-voltage ones put out tremendous current, enough to put you into convulsions or stop your heart (50 joules) if applied correctly. These devices are amazingly cool to work with -- better than batteries when you need high current, outstanding AC line filters, and terrific party toys when you need some bang for your buck. They can also turn around and bite you on the arse without warning...

Posted by kelseymh 9 years ago

Charging BoostCaps

I recently got a few of the 3000 farad 2.7 boost caps from electronic goldmine.  I have a quick question about charging them.  Applying a higher than rated voltage before the capacitor is charged all the way would be fine, right?  The voltage drop should cause the source voltage to approach 0, thusly below the 2.7 volt rating.  As an extreme example, lets say you simply hooked up a 9 volt battery to it.  Since the battery can only supply like 200mA, the voltage drops to nearly 0 as the capacitor appears to be a dead short.  The dielectric (or ion exchange or napheon membrane or whatever it is in a ultracap, lol) should be fine, correct? My main goal is to later hook up one or two of these for a regenerative brake system of something like a small gokart or bike or something.  Stopping at 30mph is like (assuming 200kg total mass) 20k joules, and each one can hold about 10k joules, and assuming a max efficiency of like 30 or 40% (I think itd be much lower, though), these capacitors could brake a gokart going fairly several times without having to be discharged inbetween cycled (but of course they would be).  For braking, could these essentially be hooked up directly (of course with pwm, and other things, but in essence:) to the motor with a little protection circuitry to prevent overcharging the capacitors?  Or would the higher voltage instantly puncture and destroy the boostcap?

Posted by guyfrom7up 7 years ago

Electronics for five year olds?!

Hi everyone, I joined the forum and became a member because I'm getting rather starved for ideas... A community centre (or center as you spell it south of the boarder) asked me to design/ come up with some drop in classes for children and their care givers. Some kids could be as young as five, and they want the class to have an electronics, hackery, tech based focus. I've done this with 12-17 year old, but this 5 year old thing is throwing me for a loop. I'm thinking about joule thieves and home made robots, but does anyone else know of a project that's gone over really well with young kids they can share at all? I'm not sure if this is in the right category, apologies if it isn't.

Posted by youhearditherefirst 10 years ago

Please use better SUBJECT lines

It would be REALLY NICE if when people posted a question in the forums, they put some useful information in the subject line so that people who might answer the question would have a quick clue as to whether they can help. Here are some particularly bad recent examples:Please tell me if this will workI need some help on a project.I need some helpQuestion?And to be fair, here are some subject lines that were OK to excellent (I was only interested in half, but at least I could tell from the other subject lines that I wasn't interested!):Help programming a 8 pin eepromAirsoftJoule Thief Troublesyour favorite song?

Posted by westfw 10 years ago

Help upgrading CFL circuit? Want to drive cfl's up to 25w.

Hello I have built this circuit, it can drive cfl's up to 15w, how do i modify it so that it can drive cfl's up to 25w?  I am using D313 for his project as the D882 didn't gave me the results i needed. Using 12v battery. Here is the original instructable link (This question is optional) Do u think the transformer i made for this circuit can be used for the famous Jeanna's light (Joule's Thief). If yes then how it would connect on the circuit? I will be making two or three more transformers like this. Do u think it needs modifications for its working like number of turns for the primary, secondary and feedback, different wire gauge?

Posted by Clarkdale44 4 years ago

Capacitor bank for Coilgun help please!

I havetwo 680 uF capacitors, rated for 200 volts.. And I want to use a disposable camera charger to charge them both. The camera charger stops at 300 something volts, and when I wire them up in series, I get 400 volts, right?.. I want to charge them and discharge them into a coil of wire to launch a projectile at a fair velocity. , I can work with up to 10k wraps of wire, and i have only two capacitors and a major one.. First 2: 680 uF 200v 680 uF 200v Major one: 180 uF 400v Now I imagine I'd get more joules with the two smaller ones than the big one because of the microfarads, right? These specific type of capacitors are made from Elite, and are electrolytic I think, and I got the major one from a computer CRT monitor, and the two smaller ones from a computer power supply.... I also have a 3.3uF 50v capacitor. Now the question is: Can someone help me add these together to increase maximum joule output? I want to hook up the two 680 uF 200v capacitors in series to get a maximum voltage of 400. Then I want to add the major capacitor, which is 180 uF in parallel with the two other capacitors to increase microfarads, in this case, it'd be: 680 680   + ------- = 680 (because they are in series) ------- + 180  = 860 I want two capacitors in series, and the major in parallel, increasing voltage to 400 volts, and the major capacitor doing nothing but adding capacitance (IF possible) Sorry, this is alot to ask for you guys to answer, If none of the above can work, What would work better, the two 680 uF's in series, or one big 180 uF 400 volt capacitor? I apologize if I cannnot explain my question properly.... it's very hard to understand capitance and series/parallel blah blah mumbo jumbo. Thank you.

Posted by Justdoofus 7 years ago

(newsletter) TV-B-Gone kit, LED Bike Jacket, Tetrahedral Kite...

Sign-up for this newsletter: Welcome back! Get the LED Out! Contest - Enter any Instructable that involves LEDs, and win some amazing lights from Monkeylectric! Mother's Day Contest - Help decide who wins a Singer sewing machine! Vote now! The winners of the Epilog Challenge have been announced! See who won the Epilog Zing laser, and gift certificates for lasercutting by Ponoko!Coming next week...Show us an amazing sound-related project, and win an awesome set of hand-built custom speakers in our upcoming Art of Sound Contest! Make Your Own Laptop Skin Light for Life: Glowing Button Cycling Jacket TV-B-Gone Kit Make a Wire Wrapped Ring Make it glow, and win Monkeylectric lights! See who won the laser cutter! No-Solder, Funny Robot in Minutes Make Your Own 29er Bicycle! Stirling Engine Rotating LED Throwies Fancy Steampunk Blunderbuss Rifle Joule Thief Night Light Tweet-a-watt - the Twittering Power Meter Cheap Light Box Fly a Bell Tetrahedral Kite Vote for your favorites! Get the grill ready! Turning a Wine Bottle into an Oil Bottle Homemade Ripstik / Waveboard Planter from Pallets, No Nail Pull Method The Sigh Collector Sign-up for this newsletter:

Posted by fungus amungus 9 years ago

Start Fire with Air, Free Cinnamon Bread, Take Beautiful Pictures...

Sign-up for our newsletter here. Jan. 31, 2008 Welcome back! Be sure to remember to enter the Get the LED Out! Speed Challenge to win a TV-B-Gone kit! The Lion Brand Yarn Challenge is open until February 17th, and we'll be announcing the winner of the $15,000 VersaLaser on Monday! ! We'll be announcing some great new contests next week, so be sure to check the homepage! Check out these cool instructables! Start a fire with air To do this we need to make a firepiston, which is a device for starting cook, camp, and signal fires with air. posted by watermelon on Jan 28, 2007 How to Make Kettle Corn Kettle corn is a slightly sweet, slightly salty popcorn snack that is quick to make and easy to enjoy. posted by GRitter on Jan 27, 2008 How to make a "Beauty Dish" flash modifier Beauty dishes are what pros use to make their flash lighting diffuse and, as the name says, beautiful. Make your own for just a few bucks. posted by thenickboy on Jan 28, 2007 Cat Burglar Joule Thief Make sure your batteries are completely dead with this cat burglar that "steals" left over joules. posted by unknownuser2007 on Jan 26, 2008 Modular Water Jug Storage Bins Organize your odds and ends with the almighty stackable water jug. A tidy workspace is one drink of water away. OK, several drinks. posted by randofo on Jan 29, 2008 Light it up in thisSpeed Challenge! How to Make Fake T-Shirts using Photoshop (Photojojo) Instructables has teamed up with Photojojo bring you some really cool photograph tutorials, like this one for a fake t-shirt logo. Fix the Red Ring of Death! (without towels!) Fix your Xbox 360's RRoD by yourself, without towels or soldering irons! posted by Dr.Professor_Jake_Biggs on Jan 29, 2008 Free Baked Cinnamon Garbage Take advantage of surplus materials and start baking your own free cinnamon bread. posted by TimAnderson on Jan 24, 2008 Crossed IR Beam Camera/Flash Trigger Trigger a camera or flash unit automatically when an object (target) enters a specific location. Great for mid-air shots. posted by tyler_durden on Jan 24, 2008 Desk-top Soldering Press! Getting tired of heating up your soldering iron just for one wire connection? Make your own soldering press and do it in a few seconds. posted by kruser495 on Jan 26, 2008 Make your own cnc controller Build your own CNC controller for next to nothing from rubbish. posted by charcoal999 on Jan 26, 2008 Show us your yarn! There's still time to enter pictures of your yarn projects in the Lion Brand Yarn Challenge!! Here are some more of the 260 projects already entered - check them out, talk to the crafters, and get inspired! Scarves Socks Cthulhu Mittens Sweaters   Now go make something awesome, and I'll see you next week! - Eric

Posted by fungus amungus 10 years ago

Weed Whacker-Powered Bicycle

This is a bike I built a year ago. It uses a 30.5cc (about 1.5hp) weed whacker engine for propulsion. A version of the same thing was on Instructables, and that's what partially inspired me to make this. ;) The engine mounts are made out of wood, because I still have not learned to weld, but they hold up just fine. The engine is an ten-year-old Echo weed whacker. It has 10,000 max RPMs. The bike peg attached is 2" in diameter and gives about 25mph top speed. There is no clutch! The one that came with the engine was way too flimsy for a vehicle like this so I took it out. Saved a lot of space, too. For the throttle, I disconnected the back brake line and connected it to the engine. The front brakes are still intact, and you can turn the engine off to slow the vehicle as well. I added the extra heatsink to the engine to help keep it cooler, as it was never meant for this kind of exertion. It gets as hot as the engine, so I guess it conducts the heat away pretty effectively. There is a 10-LED bargraph to show the engine temperature. It uses an LM3914, an op-amp, and a thermistor. There is also a 555 to drive a buzzer when it gets too hot. The bike has head and taillights that are both driven from a joule thief. They are not very bright; they are more for being seen than to see. Here's a youtube video, taken almost a year ago: Some more photos and a little more information:;=656 Comments/criticisms? :)

Posted by 1up 8 years ago

Observing single photons (may be future Instructable)

In a thread on building a DIY Geiger counter, I mentioned that it's possible to do an experiment to see single photons directly with your eyes. This is a lab we did when I was an undergraduate, more than 20 years ago. I haven't done the setup myself since then, so I'm just going to describe it; if I have the opportunity run it again, then I'll make an I'ble.If someone else decides to tackle it, please feel free to write it up yourself!The human eye detects light via a family of proteins called opsins. Different forms of photopsins are sensitive to different wavebands, which is what gives us color vision. Rhodopsin is sensitive mainly to greenish-blue light, and provides us with monochromatic night vision. Rhodopsin works by changing its conformation when it absorbs a photon; that change of conformation allows ions to flow through the rod cell's membrane and generate a signal. The signal from each rod cell is processed through the retina and passed to the visual cortex, where a representation of the visual field is constructed.Human rhodopsin has a quantum efficiency of about 25% (there's a 25% chance a single photon will be absorbed and produce the rod-cell signal). By comparison, cat rhodopsin is more than 90% quantum efficient. 25% QE is sufficiently high to be observable -- a source of single photons can be seen by a dark-adpated person with normal vision.You'll need a steady source of well-collimated photons. A green laser pointer (~532 nm) will do nicely. But how many photons does it generate? A wavelength of 532 nm corresponds to 3.53×10-19 joules. So a small 1mW laser pointer puts out 2.8×1015 photons per second (watt = joule/s). How do you reduce that to one photon at a time? With filters. An ND3 neutral density filter reduces the output light by 10-3 compared to the input, so a stack of just five ND3's in front of this laster pointer would result in (on average) just 2.8 photons per second! A stack of four ND4's would give you 0.28 photons/s on average.If you don't have neutral density filters, you can make a decent approximation, by stacking sheets of black trash-bag plastic. To make this work you have to measure the attenuation yourself, so you'll need a photodetector, something which gives an output (voltage, resistance, current, whatever) proportional to the intensity of light.Once you have your single-photon source, you need to set it up in a completely dark room. If you have access to an old-style photographic darkroom, use it. Otherwise, use thick (3-5 mm) black felt and gaffer's tape to seal any windows and doorframes. Put the laser on a table or stand pointed at your face, with the stack of NDs (or trash bags) in front of it. If you're doing this by yourself, you may want to have a piece of tape set up to hold the pointer's button down. Otherwise, your lab partner will take care of it.Sit in the dark for 20 to 30 minutes. This will seem like forever, so you may want something to help you keep track of the time. A standard CD will be about half finished, or you can get through ten pop sons on your iPod, when your eyes become dark adapted.Turn on the laser. You'll see intermittent flashes all coming from nearly the same place in your visual field; if you turn your head, the location will move in the opposite direction. If you've used filters to get down to a few flashes per second, POV will make them easier to see. At less than one photon per second, you'll see them individually.

Posted by kelseymh 9 years ago

Get the LED Out! Speed Contest Winners Announced

Instructables is happy to announce the winners of the Get the LED Out! contest. As this was a speed contest, all of the voting was done by YOU and (for the random prize) a plastic bin.To see the full list of entries simply check out the group. For a speed contest, the quality and quantity of the entries was pretty amazing and there are several that deserve to be looked at and appreciated. A big "thank you" to everyone who entered and showed us all the cool things that can be done with a tiny light.But enough about that... on with the winners!Pageviews and Ratings Prizes - For receiving the most pageviews and the highest ratings, the authors of these Instructables will each receive an Instructables Robot t-shirt, an Adafruit Industries TV-B-Gone kit, and $75 worth of LEDs from Phenoptix. Ratings Awesome led cube by AlexTheGreat Page Views LED Mood Jar! by joejoerowley Notes about the winners: While it is a great Instructable, Make your own Roll Up Keyboard was disqualified from winning a prize in this contest since the Instructable didn't involve putting any LEDs into the roll-up keyboard. Also, the Awesome led cube was the top of both lists, but was selected as the Ratings winner since it had the bigger lead in Ratings, by ratio, over the second than it did for Page Views.Ratings Prize Runners-up - For receiving the next highest ratings, the authors of these four Instructables will each receive an Instructables Robot t-shirt. Cat Burglar Joule Thief Desk-top Soldering Press! (with L.E.D) LED Light Drawing Pens: Make an LED Blaster Random Prize - For being lucky enough to have its name pulled out of a plastic bin, the author of this Instructable will receive an Instructables Robot t-shirt, an Adafruit Industries TV-B-Gone kit, and $75 worth of LEDs from Phenoptix.and the random winner is...this heartfelt Instructable.

Posted by fungus amungus 10 years ago

Getting more power from a quartz clock movement

Using a transistor to boost the output from a quartz clock to drive a larger motor in steps. Is the idea sound what would I need? Having read a couple of instructables on equitorial drives, I found myself wondering why you couldn't just use a quartz clock movement to drive one? They don't produce much torque is the answer to that one. Why not? I took one appart to find out. The gear chain is very flimsy moulded polyethylene, or maybe nylon. the power comes from a tiny armature that makes 1 turn a second in 2 pulses the magnetic pulses are provided by a little cuircit board with the quartz ossilator on it. Here endeth my actual knowledge. My knowledge of electronics is minimal give me a good set of instructions and I can build it (unless its a joule thief but thats a different matter) but don't ask me how it works. My limited understanding of a transistor is if you put a small current or voltage across 2 pins you can get a bigger current or voltage to flow across one of them and the third, something like a relay. I was thinking if I took the out put from the quartz cuircuit that provides the magnetic pulses and used it to trigger a transistor to pulse a higher voltage and current through a small 3 pole motor kicking it around 1 pole per pulse. The motor I have a salvaged and rebuilt in an earlier instructable runs on 3V and draws 0.2A when not under load. the largest motor I have to hand is a big 7 pole one designed to power model planes or cars draws up to 15A on 7.2V the timer cuircuit for that one needed 3 Mosfet's in parralle so I'm guessing thats not possible.

Posted by Stan1y 4 years ago

Scientific thinking in the classroom?

Hi, So recently I have received a very open assignment from my English class. In my high school we are having an independent study, during March. I have decided to do some research and hopefully a project about scientific thinking. I was reading Absolute Zero, and the Quest for Cold when it struck me how open scientific thinking, and research was open to many people. Famous scientist like Joules, who was a brewer, had whole other careers besides their scientific research. And even more recently, Bill Nye style science, where anyone can follow along at home, is not seen any more. Shows like the 11th Hour, and Jimmy Neutron make science into some thing distant, and limited to a special few. I see sights such as Instructables as the counter movement to that. Inviting all sorts of people, to experiment, build and learn about science themselves. Especially I enjoy reading about the green projects, because it represents a change in thinking, where everyone can pitch in to make a difference and every experiment and gadget is worth exploring for the sake of the planet. With my class I would like to highlight how open scientific thinking really is. I am wondering if anyone can think of a project with the right amount of wow factor, and educational value, to highlight the individuality of science and engineering that instructables so well demonstrates? I would like everyone to walk away thinking, "that experiments and science research is with in my reach, and that I could make a contribution to it if I want to." The ideal/mythical project that I am thinking of doesn't need to demonstrate any scientific principal specifically. In my research so far I have liked the green projects, because I believe that from those projects and thinking seen on instructables, real progress will be made to help people and the world.Thanks! Alwaysmod

Posted by alwaysmod 9 years ago

Technology Category: Artificial Intelligence/ Machine Learning/ Data Science

I would like to see AI/ Machine Learning/ Data Science be a Subcategory in the Technology Category on Instructables. The field of Data Science/ Machine Learning is on the rise. Machine Learning is being integrated into various products & services we use on a daily basis. Below is the Developer Roles chart from the Stack Overflow Developer Survey 2017; It shows that the field of Data Science & Machine Learning combined accounts for approximately 12% of those surveyed, compared to the combined 1.6% in 2016. A large number of Open Source Machine Learning libraries like TensorFlow, SciKit, etc have been made available to developers across the world. These libraries enable developers & engineers to integrate ML models, Computer Vision, Chat Bots, Speech & Text recognition, etc into their projects. The Google Assistant & Amazon Alexa AI both AI Assistants are now compatible with the Raspberry Pi. Android Things - An OS built for connected embedded systems which can run ML & AI programs is now compatible with Hardware Platforms like the Intel Edison/ Joule & the Raspberry Pi. Platforms such as OpenAI conduct fundamental research & provide free software for training, benchmarking & testing AI. Kaggle - a website for hosting Data Science Competitions has a large collection of high-quality public datasets. There are many other platforms & frameworks like these. With the growing number of resources being made available in these fields, it is only natural that a large number of people will be looking for tutorials & instructions to help them integrate these resources into their projects. Instructables could become the repository of ML/AI based projects. E.g: AI-based Security System, a Line following robot which uses ML algorithms to follow the line, etc. I hope we can have a constructive discussion in the comments as to how we the Instructables Community can make Instructables the best repository for AI/ML projects.

Posted by Jonathanrjpereira 1 year ago

Few questions about coil physics and capacitors.

Hello.  Hopefully there's some smart electromechanical and physics guys on this board. Long story short I have been working on a coil gun project for about a month now. Originally I was using disposable flash camera circuit, a simple push button, and a coil I took out of a fan. The coil itself is roughly 42 gauge wire, wound an inch long with about 14-18 layers. I achieved best results from this coil, about 4% efficiency, using a 200v 470uf capacitor and a magnetic projectile. However when I used a more powerful capacitor rated at 400v 820uf efficiencies were much lower. I realized the coil was limited and the capacitors energy wasn't being maximized. So I bought some 16 gauge magnet wire to wind a new coil. I wound a coil 40mm long, 3 layers thick around a 1 cm pvc pipe. The coil works but once again there is a huge loss of efficiency at higher energies.  So I need to wind a new coil.  Now here are my questions. 1.  I have read that a coil should be about 33% longer than the projectile.  Is this accurate? 2a.  Is there a magical equation to determine the number of layers a coil should have if all other factors are known? 2b.  How many layers of 16 gauge wire should I use for a coil wrapped around a 1/4 inch barrel to maximize efficiency with a 400v 820uf capacitor?  What about a 200v 1200uf capacitor? 3.  Could someone please demonstrate how to convert farads into amps? My main objective is an optically triggered multi stage coil gun with kinetic energy transfer of above 30 joules. I've moved away from flash camera circuitry and am now using dc to dc converters to charge the capacitors.  I need to find out how to convert farads into amps to figure out what kind of transistors I need for the trigger switch.  Any help is truly appreciated.

Posted by MurdaMastaMike 6 years ago

DIY Electronic Salvaging Database / Website [team needed]

Hello, I am a web developer by trade and have fallen in love with physically computing things. I use Instructables regularly to gain inspiration for my out projects here at home.  The magic of Instructables, for me, is the sheer massive amount of ways to re purpose our electronics. Some articles here document devices more thoroughly than the manufacturers themselves. When I was following TinkerNut's Instructable to make a 3D printer I had a spark of an idea, and I've never bought electronics the same since. While deconstructing DVD drives, and regular paper printer I was playing the stepper motor lottery. This printer has a stepper, this one doesn't. Well, I can basically walk into a Goodwill now and pick up a stepper motor any time I want now that I know what to look for. When I was following an Instructable to make a joule thief I knew that somewhere in my head of dead tech I had to have a NPN transistor. I just had to! But I had no clue where to begin looking. There were transistors of all shapes and sizes, some with text some without. I learned a lot of different transistors this way.  I am currently working on a Beta for a website I want to make. I don't want to buy the domain just yet until I get some feedback. This is a content driven database so I am looking for some help. Teamwork Makes the Dream Work! The Idea Well, the idea is to create a website / database that you can go to and type in Stepper Motor and be presented with a list of different stepper motors. When you click on a type of stepper motor you will see a list of products that contain this or similar stepper motor. Then you can hit a thrift store (my local Goodwill always has a ton) and grab the right thing, the first time. On this list of stepper motors there will be a list of Instructables using this part. In this way the site will work alongside Instructables to enhance and instruct the community. (note: I hope this isn't seen as a threat by Instructables, because its not) Also, now when buying tech I am able to analyze the product for its value, resale value, and re-purposing value. I can snag a cheap LCD from the Dollar Store or even NPN transistor if need be. Possibilities Users can salvage and sell themselves? Partner with Instructable community? Horde salvaging - (user 1 wants C02 cartridges, (user 2, 3, 4, 5 send cartridges to us (free box) and we send them to people putting them to use. Looking for some people to help me nail down the idea and beta test database functionality. Let me know if you have any ideas or want to join the effort. I really think this could be extremely useful to us who don't like to waste, especially precision instruments such as stepper motors and NPN transistors. This is for way more than just those though. Cheers! 

Posted by AlphaNomad 2 years ago