Mechanical Pianist: robotic hands that play any MIDI file
An open-source browser app built with Claude Opus 5.5 where two robotic hands play a MIDI file on an upright piano.
The full story
The maker wanted a MIDI player in the style of the Westworld intro and was annoyed by unrealistic piano playing in media. Built with Claude Opus 5.5, it shows two robotic hands playing a loaded MIDI file on an upright piano with a cinematic camera.
Fingering is based on Parncutt's research, inverse kinematics positions the joints, and the animation is deterministic so you can scrub through a song. The post says an absurd piece like Rush E makes it go "a little nuts".
How it was done
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Sources
From a short post by the maker, so the details are as they tell them.
- Reddit: Robotic hands that play any MIDI file on a piano in real time
The maker's post on r/ClaudeAI.
The subreddit's moderators removed it, but the original is still readable (it can take a few seconds to load): archived copy of Reddit: Robotic hands that play any MIDI file on a piano in real time (opens in a new tab)
- The project: csimpkins22.github.io
Linked in the post.