A Teensy 3.6 is used to run the show, acting as a USB-MIDI interface so the toy can be controlled ... The toy’s speaker is cut off and used as an audio output instead, allowing the toy to ...

[TheSpodShed] decided to whip up a USB MIDI interface for the chip, with the help of the Arduino Pro Micro. The Arduino Pro Micro is a Sparkfun creation, using the ATmega32U4 microcontroller.