This is the beginning of a new watch project called S2TinyWatch . You have an ESP32-S2 4MB opensource watch made of a small IPS Color ST7789 Display + ADXL Accelerometer + A DM3132 RTC chip + a vibration motor and 4 buttons. It is compatible with circuitpython and arduino IDE.
meybe add irda for communication.
4 button is ok but I prefer 4 button and rotor/potenciometer. Is fastest
meybe using fuzix, zephyr LUFA?