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Joule thief flashlight.

It's not the first, nor the last. but this was made almost completely from parts that were lying around.

I only bought the transistor and the case.

Toroid - computer motherboard
Toroid wrappings - Computer ribbon cable
LEDs - I have a jelly jar collection :)
Resistor, 100 ohm - left-over from previous project
Switch - Computer power switch

I credit all technological plans to 1up's "how to make a joule thief" instructable.

First, I took the standard radio shack dual AA case and removed the (-) teminal and the back plate. I stuck the terminal where the plate went and hot glued it in place. Next I wound the toriod, soldered the LEDs together in parallel, soldered everything together, and fitted it into the case in the other AA battery slot. By cutting holes in the case with my dremel the LEDs and the switch poke out nicely. After it all fit in, I sealed it all in place with plenty of hot glue. The glue keeps it all from moving and shorting.

Unfortnately, the switch has no latch mechanism, so the switch must be held down the entire time light is needed.

28 comments

Mar 11, 2010. 4:18 PMXionII says:

Simple yet effective small flashlight, the joule thief is truly an impressive circuit! The case you chose is also very sleek and low-profile. :)

That said, I would build this... but I don't have any Toroids laying around :/
Oh well, Perhaps another time.

Apr 18, 2012. 1:13 PMjacobbrunberg says:

if you have old power suply for computer you can get a feright bead go to this site its one that is pritty simple

http://www.evilmadscientist.com/article.php/joulethief

or here if you cant find one

Apr 18, 2012. 1:14 PMjacobbrunberg says:

forgot to add link

http://www.pablomontanez.com/littleupdates/2012/01/12/joule-thief-no-toroid-no-coil/

Feb 24, 2011. 4:43 PMdragontirex says:

very neat design i like it,mine use 2 white led's and one red led in the back lol :)

Jul 9, 2010. 12:46 AMedshred says:

how much would you charge to make me one with an on/off switch that i can leave on?

Jul 9, 2010. 5:56 AMBigev (author) says:

Probably very close to the cost of one with a momentary switch.

Jan 26, 2010. 1:44 PMscratchr says:

Great instructable! I built one!

Feb 15, 2010. 7:20 AMBigev (author) says:

Excellent! Always happy to inspire.

Feb 15, 2010. 1:37 AM

radiogareth says:

SInce you talk about DT I presume your are UK based? If yes then Rapid Electronics (beloved supplier to most DT departments) sell a AA switched box with a small slide switch included just like the one you have used. It's probably available eleswhere too.

Great project, I'll be trialling it soon, I've got a jar full of ex-digital camera AA's.

Jun 28, 2009. 4:49 AMzoltzerino says:

where did you get the enclsoure? It looks the perfect size. ZZZZ

Jun 29, 2009. 7:55 AMBigev (author) says:

It's a standard Radio Shack 2 AA lidded battery case. It actually was the perfect size.

Jul 4, 2009. 10:11 AMzoltzerino says:

It was an e-block transformer, I split the layers of mteal with a (now chipped) stanley blade, which I sliced my thumb with.

ZZZZ

Jul 7, 2009. 3:40 PMBigev (author) says:

You should have read my new instructable! Haha. No injuries or chipped razors,

Jul 4, 2009. 10:09 AMzoltzerino says:

Oops, I just read the last step now. Anyway, I sacrificed a pentium 2 dell to get ther toroid, hacked open a broken transformer for the thin wire and robbed school for the transistor, resistor, and led. I point-to-point soldered it and have a loose wire instead of a switch. I think it is amazing, and the DT staff are mesmorized by it... ZZZZ

Jul 7, 2009. 3:41 PMBigev (author) says:

What is "DT" exactly? Although I am puzzled now, I bet the minute you say it, i will smack my forehead and say: "Duhhhh."

Jul 8, 2009. 11:44 AMzoltzerino says:

Design and Technology, breaks down into: graphic products, electronic products and resistant materials and general DT for the young'uns.

Jun 8, 2009. 11:10 AMmagicdust says:

Nice packaging and way to show actual implementation. The hot glue really helps those freeform circuits survive actual pocket conditions and serves to help waterproof in some instances. I was slightly disappointed it was a slideshow. They aren't available in pdf format and I think your work is good enough to refer back to later. Even so, as long as the internet stays up, it is available.

Jun 8, 2009. 3:23 PMBigev (author) says:

Thanks! Although, I believe an -ible is for an original idea, while a slide show is a fair expression of an inspired idea. This is by far the most rugged flashlight I have made, by the way. Very drop proof and functionally sound.

May 9, 2009. 6:13 PMhominid says:

Idea good. Instruction minimal at best. Try to put more effort into this. Disappointing.

May 9, 2009. 10:32 PMBerserk87 says:

not everything at Instructables HAS TO BE an Instructable. try to put more effort into your comments. Disappointing.

May 9, 2009. 11:19 PMmrsplooge says:

I disagree with you. When there are a bunch of pictures with no instructions on a website branded specifically to "instructables", then it becomes a image forum. Go post on Flickr if you have no instructions.

May 10, 2009. 12:19 PMBigev (author) says:

I'm very sorry to all. Mrsplooge -you have a very valid point Berserk87 and hominid - I will improve the comments, just for you. I will also try to add more instruction. I didn't go into detail because it has been done, many times in fact. I actually did it precisely from another -ible.

May 10, 2009. 10:27 PMBerserk87 says:

my post was referring to hominid, not you. Instructables guides say very clearly, instructables, picture gallerys, and just plain showing off videos of things you've made are acceptable. its easier to criticize than to do.

May 11, 2009. 8:14 AMBigev (author) says:

That it is.
But I do believe I could have put more into it.
^{Now I need to find where that -ible is...}

May 21, 2009. 9:26 AM

Udon says:

There are already mOrE tHaN eNoUgH jewel thief guides. But not enough on how toactually package them. This instructable is very good - until now my jewel thief packaging has been lacking. Very clear pictures. I just wish people would spend a bit more time thinking before they comment.

May 22, 2009. 5:21 AMBigev (author) says:

Your kind words have inspired me to continue my packaging efforts. It's not done till ya put in in a really neat enclosure.

May 12, 2009. 7:20 AMhominid says:

Please do not be offended by my comment, I'm just naturally an obsessive compulsive grouch and I personally would not be able to do better than your 'ible, Bigev.

May 12, 2009. 9:22 AMBigev (author) says:

Please... I can take constructive critisism. Your comment only made my slideshow better. It is good to hear back from you though.