Color Changing Night Joule Thief

I got this inquiry from a teacher who teaches high school kids electronics - can we have a cool kit like Aurora mini 18, in a simpler and more affordable format? I suggested Night Joule Thief, but the teacher felt that it wasn't sexy enough for the kids. (ur... you know what I mean.)

So I combined the multi-color LED and Joule Thief in one, and got Colour Night Joule Thief. It's a mood lamp version of Night Joule Thief.

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Step 1: Features

Here are the highlights of the Colour Night Joule Thief.

    * Compact & streamlined design
    * Uses only one AA battery (or any 1.5V battery you can hook up to)
    * Easily adaptable to different size batteries - hook up holes to attach home made clips
    * A multicolor/color changing LED
    * Automatic turn on via a light sensor (adjustable sensitivity level)
    * Energy efficient - works even with a run-down battery, down to 0.6V
    * Makes a great little mood light

ledartist (author) says: Nov 28, 2012. 10:31 AM

This popular kit is now available at The Maker Shed!

http://www.makershed.com/Color_Night_Joule_Thief_p/mkla1.htm

Thanks!

jayz01982 says: Apr 2, 2013. 9:17 PM

do you have branch here in the philippines? so that i can order it here

ledartist (author) in reply to jayz01982Apr 3, 2013. 6:58 AM

Hello!

I don't have a branch or reseller in Philippines, but I ship there. Please go to www.theledart.com, and shop.

Thanks,
Aki

lgore93 says: Mar 2, 2012. 6:48 AM

Do you think I could maybe replace the PCB with a couple of popsicle sticks glued together? I know that sounds kind of ghetto, but I'm looking for a very inexpensive project to do in class. It would be much cheaper if I could make a working model on popsicle sticks. I know it wouldn't look as professional, but things would be much easier.

ledartist (author) in reply to lgore93Mar 2, 2012. 7:27 AM

Yeah, you should definitely try that. Please post the result!

Aki

lgore93 in reply to ledartistMar 2, 2012. 7:36 PM

Okay thanks! One more question which is probably obvious... The smallest photoresistor I can buy from the site I usually order from is 5k-0.5M ohm. Would the circuit work with this difference? I realize 2k ohms is a significant amount, but is it really that much on this scale? I admit that I know much less of electronics than I would like to, but I love learning and building new things. Thanks for your help.

ledartist (author) in reply to lgore93Mar 3, 2012. 8:00 AM

That will probably work. I'd just try it, maybe on a breadboard.

Aki

lgore93 in reply to ledartistMar 24, 2012. 9:28 AM

My parts came in yesterday, and I built it. It's not the prettiest thing in the world, but it works very well! I decided to use a piece of cardboard instead of popsicle sticks since it allowed for some less than... perfect wiring. Also, I found out I was out of electrical tape so I had to substitute duct tape in. Haha

hussainsk in reply to lgore93Jun 23, 2012. 3:32 AM

i was prepared to electromagnet 9v battery how much turns required 24 gauge wire

waterlubber in reply to lgore93Jun 5, 2012. 1:00 PM

Mechiver electronics! Woot!

ledartist (author) in reply to lgore93Mar 26, 2012. 6:56 AM

Umm... You are good.

Nano_Burger says: Jun 12, 2012. 12:59 AM

LED Artist,

Can you use different voltage batteries with this circuit? O have 3v, 6v and even 12v photo batteries I'd like to drain off as well. They are probably not up to those voltages since they became too weak for their particular device so a few volts short.

ledartist (author) in reply to Nano_BurgerJun 12, 2012. 7:19 AM

If the voltage is below 1.6V or so, then it's safe to connect to this circuit.

ciliar says: Mar 25, 2012. 9:04 AM

Aki, you are a star - soon to put Colour Joule Theif into action! Keep you posted!

ledartist (author) in reply to ciliarMar 25, 2012. 9:59 PM

Thanks!
Yes keep me posted.

Aki

markallie says: Mar 13, 2012. 3:42 PM

In the pdf version of the schematic an MPSA05 is listed as a choice for the PNP transistor, Q1. It is an NPN transistor.

ledartist (author) in reply to markallieMar 13, 2012. 4:51 PM

Thank you for pointing this out. I've corrected the error.

Aki

GASSYPOOTS says: Feb 23, 2012. 2:44 PM

how bout a self charging/ no batterys needed after 1st charge

64bitgenius in reply to GASSYPOOTSFeb 27, 2012. 7:32 PM

unfortunatly, I don't think thats realistically possible. the reason for that is that it is going to lose energy no matter what. if it were 100% efficient, it would be possible, but it's not.

sageserver says: Feb 23, 2012. 8:41 AM

Can another LED be used in place of D1? or is the voltage difference too much? Very instructive instructable.

ledartist (author) in reply to sageserverFeb 23, 2012. 9:59 AM

D1 is there to rectify the voltage, so it has to be regular diode. LEDs have too high of forward voltage drop.
If you wan to drive two LEDs, you can simply add another LED in series to D2. The brightness will go down a bit, but it will still work.

Aki