DIY watches often consist of a PCB and screen wrapped in duct tape. I wanted to change that by designing a 3D-printed case. It is closely oriented on the Pebble Time.
- Microcontroller: Atmega328p with Arduino boot loader
- Real Time Clock: Maxim DS3231 (<2min per year deviation)
- Display: 96×96 pixel Sharp Memory LCD (LS013B4DN04)
- Battery: CR2025 160mAh coin cell
- The AT mega is in Sleep mode for most of the time and only runs once a minute to update the time or if a button is pressed. This reduces the current consumption to 2uA. Sady the display needs a certain pulse every second, which requires a complicated additional circuit. Because of this the current consumption is around 20uA. This still makes for around half a year of battery life.
- User Interface controllable with three side buttons. Buttons are 3D-printed and activate switches on the PCB
- Tells time, date, temperature and battery voltage on the main screen. No additional temperature sensor is needed, because the DS3231 already has one integrated for temperature compensation.
- Flappy Bird clone (“That would have been cool in 2013″)
- The case consists of four 3D-printed parts. It has a thickness of only 10.8mm, which is thinner than the Apple Watch. Unfortunately it lacks screen protection.
- Fits any 22mm Watchband
Starting with the battery life, the watch has now been running since August 7. In a previous project log I showed that the calculated run-time would be up to 6 months, which has been achieved now. The voltage has dropped to about 2.8 V, so it might last for a couple more weeks.
Additionally the source code is now online on GitHub: https://github.com/CoretechR/Chronio
As the PCB and 3d printing files have already been released, there is nothing more you need if you want to build your own copy of the watch.
Read More: Chronio – Low power Arduino based (smart)watch