instrument-a-day 27: remote control
That harpsichord bit at the beginning kind of sounds like Dead Can Dance, no?
An IR decoder plugged into an Arduino intercepts codes transmitted by remote controls. Simple software uses the manufacturer code to choose a MIDI channel, and the button code to choose a note. It plays a single percussive note for remote codes it can't understand, like the Bose.
That synthesizer is 25 years old, and the NAD remote control probably almost the same.