Bangle.js 2 is based on nrf52840. For nrf52840 based prototype I'd suggest to get Magic 3 a.k.a C17 watch as it is quite cheap and the hardware is reverse engineered.The Bangle.js seems like a great option but it would be too pricey for me to use as a basis for a product.
https://www.aliexpress.com/item/1005005373233740.html
https://www.aliexpress.com/item/1005005935723945.html
https://www.aliexpress.com/item/1005006326191697.html
some info about the hardware here https://github.com/fanoush/ds-d6/tree/m ... 3#hardware
It is relatively easy to update with your custom firmware without taking the watch apart. If you brick it you need to take it apart and use SWD.
There are also many other watch prototypes based on ESP32 or even RP2040 or RP2350. I am mentioning this one since you mentioned bangle.js. Also it is a real watch with good power management, it can last month or two with BLE advertising turned on.
Statistics: Posted by fanoush — Thu Apr 24, 2025 1:51 pm