Teensy 4.0 driven by musically selected frequencies from a table of 7 octaves, 33 musical modes and 12 keys. Random selection of ADSR values as well as FFT LED spectrum visualizer colors; favorites can be saved to EEPROM for recall. Junk housing that got my attention- arduino mega drives the pink scaler display measuring output voltage on a channel of the teensy audio adapter. Just finished a battery powered handheld version :)