I need help with my school project fast!

Thread Starter

Riad Guzin

Joined Nov 13, 2017
2
So i am working on a school project where I use LED diodes as solar panels to power a weak bulb.I got the idea from this Video :
. But since I live in a backwaters place, I couldn't find the exact same LED diodes as this guys but I found something similar.Me and my grandpa connected the LED tracks (5 of them) in series and tried to measure it with a very old Voltmeter,but there's nothing.Here's a photo of what I made:



I hope someone can help my with my problem.I tried doing the same thing outside with plenty of sunlight but still nothing. :( (I know i'm a newbie to this so please,no harsh comments,I just got into this stuff)
 

GopherT

Joined Nov 23, 2012
8,012
So i am working on a school project where I use LED diodes as solar panels to power a weak bulb.I got the idea from this Video :But since I live in a backwaters place, I couldn't find the exact same LED diodes as this guys but I found something similar.Me and my grandpa connected the LED tracks (5 of them) in series and tried to measure it with a very old Voltmeter,but there's nothing.Here's a photo of what I made:

I hope someone can help my with my problem.I tried doing the same thing outside with plenty of sunlight but still nothing. :( (I know i'm a newbie to this so please,no harsh comments,I just got into this stuff)
You are using white LEDs. White LEDs are really UV LEDs with a mixture of fluorescent chemicals in the lens of the LED that emit a combination of visible colors (red blue green) or (cyan, magenta, yellow) to ultimately make white light. The chemical mixture is called a phosphor.

So you really have three problems. One, the sunlight is blocked by the phosphors. Two, very little UV energy from the sun penetrates the atmosphere so you have little energy to start with.

Finally, there, (your biggest problem), voltage and power are two different things. Just because the video shows 2.0 v available, as soon as any load is applied, (your bulb for example), the voltage will fall to near zero.
 
Last edited:

Thread Starter

Riad Guzin

Joined Nov 13, 2017
2
You are using white LEDs. White LEDs are really UV LEDs with a mixture of fluorescent chemicals in the lens of the LED that emit a combination of visible colors (red blue green) or (cyan, magenta, yellow) to ultimately make white light. The chemical mixture is called a phosphor.

So you really have two problems. One, the sunlight is blocked by the phosphors. Two, very little UV energy from the sun penetrates the atmosphere so you have little energy to start with.
So which LEDs should I use?
 

OBW0549

Joined Mar 2, 2015
3,503
So which LEDs should I use?
None. Pick a different project.

For the reasons @GopherT cited above, plus the fact that LEDs have only a tiny surface area with which to collect light energy, LEDs make extremely poor photocells because the amount of current they can deliver to a load is minuscule, nowhere near enough to power even a "weak bulb."

Also, do yourself a BIG favor and don't seek electronics knowledge from YouTube videos; 99% of what's out there-- including the video you posted-- is worthless, amateurish garbage that will only lead you astray and cause confusion.
 

WBahn

Joined Mar 31, 2012
26,033
Or another option is to use this project, but approach it from the standpoint of debunking the YouTube video. Determine the drive capabilities of the circuit that you have constructed and compare that to the what would be needed to light that small lightbulb. Since anecdotal evidence is only suggestive that the video is bogus, do some analysis of the energy available assuming your LEDs were 100% efficient converters of light energy to electrical energy and go from there to determine how realistic the video's claims are.
 

hobbyist

Joined Aug 10, 2008
887
I don't think the video was a fake, it was not showing it to be a voltage supply, but just that it can produce a voltage.
As he was passing his hand over the array different voltages were produced.
This project has very little capability to drive a load, however it looks to be an excellent choice for being a signal source, after determining the impedance of the entire array, design a amplifier with high input Z. for this to drive.
 
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