Picture of 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.
Schmidty162 years ago
Whats the case that ur suing
cdroman2 years ago
Please anyone help me. I cannot find anywhere how I can make joule thief flashlight with 3.7V cellphone battery or laptop battery. Everywhere people use 1.5V battery. What is the sheme for 3.7V. I have made a flashlight with 5 leds and 3.7V nokia cellphone battery, but it last for ~10 hours. After the voltage drops around 3V it gets dimm. So,..any ideas about the .....toriod....resistor value? Thanks in advance.
XionII5 years ago
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.
if you have old power suply for computer you can get a feright bead go to this site its one that is pritty simple


or here if you cant find one
forgot to add link

dragontirex4 years ago
very neat design i like it,mine use 2 white led's and one red led in the back lol :)
edshred5 years ago
how much would you charge to make me one with an on/off switch that i can leave on?
Bigev (author)  edshred5 years ago
Probably very close to the cost of one with a momentary switch.
scratchr5 years ago
Great instructable! I built one!

Bigev (author)  scratchr5 years ago
Excellent! Always happy to inspire.
radiogareth5 years ago
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.
zoltzerino6 years ago
where did you get the enclsoure? It looks the perfect size. ZZZZ
Bigev (author)  zoltzerino6 years ago
It's a standard Radio Shack 2 AA lidded battery case. It actually was the perfect size.
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
Bigev (author)  zoltzerino6 years ago
What is "DT" exactly? Although I am puzzled now, I bet the minute you say it, i will smack my forehead and say: "Duhhhh."
Design and Technology, breaks down into: graphic products, electronic products and resistant materials and general DT for the young'uns.
It was an e-block transformer, I split the layers of mteal with a (now chipped) stanley blade, which I sliced my thumb with.

Bigev (author)  zoltzerino6 years ago
You should have read my new instructable! Haha. No injuries or chipped razors,
magicdust6 years ago
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.
Bigev (author)  magicdust6 years ago
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.
hominid6 years ago
Idea good. Instruction minimal at best. Try to put more effort into this. Disappointing.
not everything at Instructables HAS TO BE an Instructable. try to put more effort into your comments. Disappointing.
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.
Bigev (author)  mrsplooge6 years ago
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.
Berserk87 Bigev6 years ago
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.
Bigev (author)  Berserk876 years ago
That it is.
But I do believe I could have put more into it.
Now I need to find where that -ible is...
Udon Bigev6 years ago
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.
Bigev (author)  Udon6 years ago
Your kind words have inspired me to continue my packaging efforts. It's not done till ya put in in a really neat enclosure.
hominid Bigev6 years ago
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.
Bigev (author)  hominid6 years ago
Please... I can take constructive critisism. Your comment only made my slideshow better. It is good to hear back from you though.