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I tried to do this exact thing years ago too! Except I only used one RGB led, and thus could never sense the red channel, because the bandgap of green and blue
by msds 10y ago
I tried to do this exact thing years ago too! Except I only used one RGB led, and thus could never sense the red channel, because the bandgap of green and blue LED dies is too big to really get any signal from red light. Isn't it annoying when your project is up against quantum mechanics?
I also build a swarm of throwies that used a single LED to synchronize their blinking. That project was much cooler, and I wish I had better documentation...
- jonathankoren 10y agoI am interested in this project.
- msds 10y agoUnfortunately, the lack of documentation thing strikes again... It was pretty simple electronically - an ATTiny25, a coin cell, and an LED wired across two IO pins, for light sensing using LED's junction capacitance as a photocurrent integrator (http://www.merl.com/publications/docs/TR2003-35.pdf http://www.merl.com/publications/docs/TR2003-35.pdf). The trick was in the control algorithm - I got things synchronizing reasonably well, but LED ensemble was prone to all sorts of weird chaotic behavior. I suppose I should recreate it, on an even larger scale. I just need to figure out some better way to power it...