Julian Straub

creations and thoughts

Harvesting Light with five BPW34 PIN photodiodes

Posted at — Apr 17, 2020

Inspired by the desire for a minimal light harvester that relies on a very small and even form-able solar cell, I recently had the idea of trying to use photo-diodes for light harvesting instead of “big” solar cells. It turns out that others have thought of this as well.

BPW34-based light harvester

To test it out, I went with the charge-pump light harvester design and adapted it to the lowest input and trigger voltage to drive a ultra-bright red LED:

The harvester blinks nicely at a surprisingly good frequency (relative to the more powerful solar-cell-based versions) considering the BPW34 rating of only \(50\mu A\) photo-current.

I am excited about the possibilities this opens up for free-forming small and creative light harvesters.