Pinetime is a sleek, open-source smartwatch built around Nordic’s nRF52832 SoC. The 1.3-inch 240×240 IPS display, six-axis accelerometer, heart-rate sensor, 180 mAh battery and tactile button are packed into a 37 mm zinc-alloy case that is water-resistant to 1 atm. Everything—from the PCB layout to the STEP files for the injection-molded back cover—is published under the CERN-OHL and MIT licenses, so you can spin your own variant or simply print a replacement shell.
Power comes from a 64 MHz Cortex-M4F with 64 kB of RAM and 512 kB of internal flash, augmented by an external 4 MB QSPI chip that stores resources, logs and Over-The-Air updates. A vibration motor, push button, capacitive touch and BLE 5.0 complete the hardware picture, while a 5-pin SWD header hidden inside the band lug lets you flash, debug or even run Black Magic Probe without opening the watch.
The default firmware is InfiniTime, a lightweight C++ RTOS-based stack built on top of FreeRTOS. It ships with the essentials: clock, notifications, music control, motion tracking, heart-rate acquisition, stopwatch, alarm and a 2.5-day battery life at full tilt. A nimble LittleVGL/LVGL scene graph drives the 60 fps UI, while NimBLE keeps the Bluetooth LE link sipping current at ≈300 µA average.
InfiniTime is modular: drivers live in src/components, the display manager uses a simple port-based message loop, and the BLE API is exposed through a set of well-documented GATT services (Time, ANCS, Heart-Rate, Battery, OTA). A companion Android app, Gadgetbridge, pairs out-of-the-box for notification mirroring, firmware upload and watch-face sync. Prefer to roll your own? A Python DFU script, an openOCD target file and a GitHub CI pipeline drop a signed .zip ready for OTA in under five minutes.
Developers get USB-C SWD dongle support, RTT printf, crash dumps to the external flash and an lv_sim_infinitime SDL2 emulator that runs the whole UI on a Linux desktop. Graphics, fonts and protobuf resources are compiled into the binary, but you can also side-load them via the external flash file-system, leaving more than 200 kB of internal flash free for experimentation.
Pinetime + InfiniTime is therefore more than a hackable wristwatch; it is a tiny, affordable development platform for wearable computing, fitness tracking or even ultra-low-power mesh experiments—fully community-driven and ready for your next pull request.
https://www.pine64.org/pinetime/
https://wiki.pine64.org/index.php/PineTime
https://github.com/InfiniTimeOrg/InfiniTime
