Some of my fellow students and I at USU are attempting to create a xylophone that is MIDI compatible for a child with autism. We are trying to set up a mechanical system where when you push a button on a MIDI controller, it will activate a mallet connected to a xylophone and play the corresponding note. We are not worried about the intricacies of creating the mechanical system and MIDI controller itself, but we are not sure on how to make the xylophone MIDI compatible. Does anyone have ideas on how to send a MIDI signal to an instrument instead of to a computer and make it play a note?

Thanks in advance for your ideas!