The first one of these I made used a photoresistor on the lid of the box, which was a bit clunky to use since it required a light source outside of the box to work. For version 2, I got myself a Digispark microcontroller and a knob to control an LED that would strobe in front of the photoresistor to pass the signal to the amp. I added a second LED to show the strobing speed to the user. This one is a bit easier to use
The finished product LED and photoresistor inside heat shrink, AKA vactrol
