The MIDI Grand Piano factory-installed in the 80s by Yamaha

The Yamaha MIDI Grand was an acoustic Yamaha grand piano fitted at the factory with an optical MIDI sensing system.
It allowed the piano to function as a full MIDI controller while retaining an entirely traditional acoustic action and sound.
It was produced in limited numbers and aimed mainly at professional studios and composers.

Specs:

• Type: Acoustic grand piano with MIDI output
• Base models: Yamaha C3E and C7E
• Keys: 88 keys
• MIDI: MIDI Out (performance data only)
• Sensing system: Optical (non-contact, no effect on touch)
• Sound generation: Purely acoustic (no internal digital sounds)
• Production: Limited / special factory version (late 1980s)
• Predecessor to: Yamaha Disklavier concept
• Factory-installed optical key & hammer sensors
• MIDI Out for controlling external synthesizers and samplers
• Velocity-sensitive MIDI output
• Key-release (note-off) velocity transmission
• Full 88-note MIDI range
• Selectable MIDI channel
• Local acoustic sound always active (no muting or silent mode)
• No internal sound engine (acoustic piano only)
• No recording or playback functions
• Designed for studio synchronization and sequencing