Casio SA-21 midi conversion

A simple project to transform an old Casio keyboard into a MIDI controller, based around the ATmega328P microcontroller and Arduino enviroment.

Main features

• Octave shifting
• Key transpose
• Adjustable note velocity
• Support for 5 midi channels

Requirements for PC connection

• Serial to USB module if using a stand-alone ATmega328P.
• Hairless MIDI to Serial Bridge for MIDI communication.
• LoopMIDI for virtual MIDI port creation.

Hardware and shematics

You will need to desolder the original chip that comes with the keyboard so that it does not interfere with the microcontroller. In my case I simply cut its pins to the key and button matrices.