Make a Solar Panel using Diodes!

Step 3 Get Funky

So you're generating voltage with your flashlight and a handful of diodes.....wow.  So what's next?  That's up to you.  You could cover a PCB with them and see how surface area corresponds to voltage, when you get diminishing returns, what the optimum diode to voltage ratio is, etc.   You could add in capacitors....throw in an op amp or even a charge pump and turn mV into V. 

I dropped $5 at R.S. and got two packs of 50 diodes and etched a PCB.  Your designs are endless.

Comments

[macman808]

what you need to do is add a joule thief to the circuit. because then you have 3 volts >:-)

[kdorji]

Good Idea .... May i have circuit diagram please or the web site where i can go though for it?

[nevdull]

That's an interesting thought. :) There are some charge pumps that operate on a very low voltage and if a joule thief circuit could boost to 3V, the charge pump could easily make that 6V or 9V, although I think the current would severely suffer. Thanks for the comment!

[macman808]

yes the current would suffer but if it didn't, some charge pumps can turn 3v into 12v and then you just need an inverter to make that 240v.

[nevdull]

I bought five 3", 5", and 7" LCDs at dirtcheap prices the other week from my local surplus electronics shop and put together a few CFL inverters for the backlights, but much to my chagrin it still required a -24V on VLED and all the charge pumps I was willing to buy (ie not over $5) couldn't invert more than 10-12V *and* perform a boost (although I saw a few more expensive ones that could and found a nice voltage tripler pump), but figured how to string them together to get

V_out = 2D - (2 * V_in)

I wonder, though, how much of an AC  voltage swing you'd get if you're pushing, say, 10 uA.  Sadly, I'm not sure it could even meet the charge pumps I_in requirements.  It would be interesting to see if you could get 120 or 240 VAC from it, though. 

[drresearch]

This is great,
I used only 2 zener diodes (I think 5v, but not sure) and got up to 2 V in parallel and even 3 V in series, though I did not manage to light up an LED. But I am planning to try buying more of these diodes and making a whole PCB full of them or something and see how much power I can get. I'll let you know.

[nevdull]

That's awesome! I'll be curious to know if you ever manage to light up that LED. Keep us posted on your progress and feel free to post any schematics/pics/etc to this instructable.
Cheers,
/nev/dull

[drresearch]

Well, I am sorry that I took so long, but finally I tried and bad news, with about 20 diodes in series or parallel the voltage is not even as much as I had got before (I am afraid they might sold me slightly different diodes in the shop, there they make confusion sometimes). I might try again, but not very soon, perhaps in a few weeks.

[nevdull]

No problem. Too bad it didn't source more voltage. Maybe a new design might help if you're tinkering out with it again! It's always fun to try new setups, I think. Thanks for the post!

[drresearch]

Well, I forgot to mention that the diodes had to be almost touching the light source (I used a 15watt CFL bulb), so perhaps it's not that great, but I will still try. I'll also post a picture most probably.

[technicum]

Hmm, by me i only get 0,05 V in full sun light. A capacitor makes no difference :S And also when the diodes become a little warm (by the sun of course) the total current drops to a little 0,02 V. I have: 24 diodes (from your description of course), all connected parallel Well, full sunlight Am i doing something wrong?

[nevdull]

I would try running some of the diodes in series. You can put two series diodes in parallel with each other ie:

-----o---------|<|-------o------|<|-------------o
       |                                                           |
 ----o---------|<|-------o------|<|-------------o
   ... ETC ...

there's a tradeoff between increasing I and increasing V when configuring your diodes in parallel or series.

[C.H]

Yes, there sure is a tradeoff. However; one could not combine these in any way, making use of both?

[deemoowoor]

Nice instructable. It would be nice to know, how much power could such a setup produce, just for the sake of knowing it. :) In fact, I think it could be used to e.g. detect light in some conditions, in case you get a shortage of photo-resistors or photo-diodes. :)

[kenfire]

What the Part number for the diode??? IN4***???

[nevdull]

try 1N4148

[draghi]

on what website?

[anthvale]

Say you had a board with 1000 diodes on it. What is the potential of one of these things? I'm looking to experiment with this a bit, how would i go about storing energy from the sun? Thanks, Anthony

[nevdull]

I'd say you'd want to look into a capacitor of some sort.

[anthvale]

Sounds good, thanks for the responce.

[garywpalmer]

Could you take your finished board with the 100 diodes out in full sun and check the voltage? Inquiring minds want to know.

[nevdull]

The PCB-of-many-diodes isn't an optimized design...it is a prototype I built after I started adding more diodes to explore the light-diode-voltage phenomenon.  in fact, it's got holes throughout where I've added capacitors (two), two potentiometers, a static resistor, etc.  So I don't think reading any voltage off of it would be representative of what a well thought-out design could accomplish, with that in mind from the beginning.  

I don't mind doing it for you anyway, if you like, but just wanted to say.  When I was outside it wasn't very sunny, but even so, I never read above 100mV.  Also, I have eagle cad schematics of the board as I built it to explore the diode-solar-power thing that I don't mind posting, either, if someone just wants some ideas.

In the meantime, here's a pic I just took outside (kinda hot, but not very sunny) with a mini-solar cell.  It was overcast when I took the pic.

Cheers!

[zaphodikus]

I'm not sure that using silicon diodes in this way is totally new, it is nice to be reminded though of how fun the universe we live in is. I really love these "makes you think" instructables. My guess is that the finnished board generates around .6V in full sun , but only in the micro-ampere power level - so it is not going to really ever power more than a single led :-)

[Motta]

I agree with gary... A pic with your finished PCB working would be great!