Optical theremin back to acoustic

New members to the Microcontroller group receive a fun "optical theremin" kit to build and play with. The output of this device is a tri-colour LED, controlled by obscuring light to three inputs.

At our last meet, Mark demonstrated an ESP8266 "Witty" board (Aliexpress), using the built in LDR and a piezo speaker to convert light back into sound.

Mark has passed on the source code to his program for us to share.