AI Smart Piano Trainer based on nRF52840

Client

A music education startup creating a retrofit learning aid for acoustic pianos that guides beginners through songs using illuminated keys.

Challenge

Designing an ultra-thin (2mm) flexible strip that sits between the keys of any standard acoustic piano, detects which keys are pressed, and illuminates the next target key.

Product Concept & Architecture

A 2mm-thick flexible PCB strip containing 88x WS2812B LEDs and 88x Hall-effect sensors sits across the keybed. The Nordic nRF52840 scans key states at 50Hz and drives the LED matrix.

Engineering Solution

The Hall-effect sensors detect each key's ferromagnetic hammer movement. The companion app sends MIDI note sequences via BLE. The on-device TinyML model analyzes the student's playing and generates a per-song accuracy score. The LED guidance uses color coding: blue = next note, green = correct, red = missed.

Result

<20ms key detection latency. Fits any standard 88-key piano without modification. 40% faster learning curve.