Beeper is a 37kB synthesizer built by Valentyn Danylchuk that runs on ESP32-S3 and ESP32-P4 microcontrollers, including the Tanmatsu handheld. It skips sequencer complexity entirely, shipping only with built-in loops so the focus stays on sound shaping through a minimal control set operated by arrow keys.
Ports exist for the web via itch.io and for Mac, though the web version has notable input latency. The embedded target is the interesting case: a functional, playable synth instrument in a 37kB ELF binary on constrained hardware is a clean engineering constraint worth examining.
Read the full piece for the embedded video of Beeper running on the Tanmatsu P4 handheld. The source is on GitHub, and the gap between how small this is and how usable it feels is the real story here.
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