Super Cheap 1.5V DIY Driver!

[FireMyLaser]

For the past few days I've been researching in this very interesting boost circuit called the "joule thief" (google it) and done allot of experiments and improvements to make it suitable able to drive red and even violet laser diodes! Right now I am able to get up to 21.7V without a load and 65mA with a phr diode as a load. It pretty much auto-senses the load and adjust the voltage like the ddl circuit. It can drive up to 20 white standard LEDs in series on just one 1.5V cell! It is still allot more work to be done, I just found out that by just adding a another 1.5V battery for a total 3V in-put I could get ALLOT more current to power a phr diode. But unfortunately that was enough current to kill my last one (I've killed 3 phr's in experimenting) by turning up the pot a little too fast :cryyy:.


The driver:

Never mind the resistor poking out, it is for current measuring.

A ferrite core with a pair of single strand copper wire winded 8 times.

Here it powers up to 10 white (with an orange case) LEDs in series on a single 1aaa 1.5V cell:

10 LEDs

5 LEDs

2 LEDs

1 LED

Here it powers up to 21 white (with an orange case) LEDs in series on a two 1aaa 1.5V cells:

10 LEDs

5 LEDs

2 LEDs

1 LED

Close-up of the LEDs powers by 3V

I never adjusted the pot between the different LED groups.


My schematic.

The original schematic from google:

*I am not able to post any current/voltage measurements right now, I need a new DMM.*

 

[Gryphon]

Cool, i built one of those ciruits a couple weeks ago, its still sitting on my windowsill. I had heard about them and built one for the heck of it and then never did anything with it. :undecided:
Although it looks like now i might have a use for it

 

[FireMyLaser]

Yeah this thing definitely has potential. I am so amazed how it works!

 

[lasersbee]

Nice circuit find... what type of Transformer are you
using... is it very small..:thinking:

Jerry

 

[moonreft]

Fantastic! I might have to jump on board and give this a go as well.

 

[FireMyLaser]

Nice circuit find... what type of Transformer are you
using... is it very small..:thinking:

Jerry

It is a hand winded ferrite toroid, I'm uploading pictures now.

 

[Gryphon]

I managed to get 17 winds on mine, i haven't experimented to see whether more or less winds effect performance thou :thinking:

 

[FireMyLaser]

I found 8-9 winds to work better. Also the longer core the better, with as thick wire as possible. I spent allot of time making different coils, this works best so far.

 

[FireMyLaser]

Updated the first post with pictures.

 

[Krutz]

nice!
i found the joule thief years ago, but didnt thought about how to enlarge it..

manuel

 

[FireMyLaser]

I hope this catch on, if anyone has an oscilloscope, please replicate my circuit from the schematic and look if the output is clean. This thing is supposed to oscillate 50 000 times per second with voltage spikes, I want to know if my modifications has gotten rid of that.

 

[charliebruce]

I have access to a scope and know the basics about using it, so if I can find a good suitable toroid then I'd be happy to give it a go. If you need any more PHRs to help with your research, I'd be more than happy to sell them to you for cost price.

 

[FireMyLaser]

Thanks I might buy a few from you, but first I need to get a new and good DMM, I'm like mutilated without one...

The toroid is from some cable I found, it is pretty common to find on any electrical device with a cable sticking out.

 

[Krutz]

..are they "full" torroids, and not two halves glued together around the cable?
i know i once had removeable ferrite "clams", like in that picture. two halfs to snap around any cable..

manuel

 

[FireMyLaser]

Mine is a solid one piece, maybe you're right that most are two pieces... I don't know how those will work.

 

[Deleted member 8382]

I hope this catch on, if anyone has an oscilloscope, please replicate my circuit from the schematic and look if the output is clean. This thing is supposed to oscillate 50 000 times per second with voltage spikes, I want to know if my modifications has gotten rid of that.

If you want to send me one I'll for sure test it on the oscilloscope on my university