[tomn]

Here's a video of a circuit I made which flashes an LED, using only power collected by the LED:

https://youtube.com/watch?v=BM7VDOoFIWI

The LED is the component on the left; there's a very dim flash (pretty much just the black die turning red) at around 11s, then every few seconds.

I can't remember exactly how it works... I think there's two capacitors charged up to the voltage of the LED in parallel through high-value resistors, and a circuit that shorts the +ve of one to the +ve of the other to put them in parallel.

It only just works at a very specific light level. IIRC some of the transistors are used as very low leakage diodes rather than transistors, as the regular diodes I had we're too leaky.

[mrtksn]

Cool, it's a self powered light meter. The more light there's in the environment the more frequent the blink. Maybe can be adjusted to have less frequent, shorter lasting but more powerful flash!

[giantrobot]

> Maybe can be adjusted to have less frequent, shorter lasting but more powerful flash!

This should be called a Goku circuit. Kaaaamaaaaikaaaaaa.

[blueflow]

Now this is the most impressive thing i've seen today! Especially because its made out of discrete components. Kudos.

[tomn]

Thanks! I'm not sure what integrated components you could use for this, as anything useful would probably use more current than the LED can provide.