There are already some watches such as Texas Instruments ez430-Crhonos and MetaWatch that are used as development platform and let you develop software yourself. Some hardware documentation is usually provided as well, but Energy Micro forums’ member hairykiwi is trying to go a bit further. He created a watch based on EFM32 Cortex M3 MCU and already released the KiCad schematics and gerber files, with 3D printer files and firmware source code to be released once they are ready. The project is called “Open source Time Machine #2” (OTM2).
The project makes use of the following components and features:
- EFM32LG332F256 – Energy Micro Cortex M3 Leopard Gecko MCU with 256KB flash and 32KB SRAM
- A 128×128 pixel (23.2 x23.2mm visible area) ultra low power Memory LCD from Sharp Microelectronics,
- Recharge and programming via Micro USB connector. JTAG programming is also available.
- 150mAh Li-Po Battery + on-board battery fuel gauge IC.
- Vibratory Motor.
- Piezo Electric diaphragm.
- ADXL362 / ADXL346 accelerometer.
- Five miniature right-angle tact switch buttons
- Provision for a LED based planar light-guide type back light (utilizing a 0.4mm high right-angle Avago ChipLED and laser engraved light guide.
The watch may be improved at a later stage with the addition of Bluetooth LE, ANT+, GPS, etc…
He has just assembled the first PCB as of last week, and it looks pretty neat.
There are no videos of the watch yet, especially since the device may not have booted yet, but if you want to see what the display is capable of, you can watch the video below with the Sharp display and an EFM32 devkit.
This open source hardware project is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License and, will be open source firmware, probably released under the GNU Lesser General Public License v3.0.
Schematics and gerber files are available in the project’s github repository, and others files (3D parts & source code) will be available as the project progresses. There are a few more pictures, and a lot more explanations about the assembly in the forum post.
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