NOTE: We have a newer and sexier revision of Watchduino, including Bluetooth connectivity, and a better look and feel. Check it out!

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WatchDuino is an open hardware project that combines inexpensive electronic components and a complex Arduino (C++) code to build a useful and reprogrammable smart watch.

The code and the components have been optimized after a lot of prototypes to provide a rich set of features with a small and cheap battery that can last more than a week without recharging. A lot of electronic and software engineering was required to make this project possible.


  • Time and date (analog and digital output)
  • Alarm / Countdown (with custom music)
  • Games
  • Pong (1 vs com)
  • Snake
  • Rechargeable battery (by USB)
  • Battery meter
  • Low-battery mode (it can last 2 years with 240mAh battery)
  • Built-in screen light
  • Compact design
  • Framework-like architecture to easily program custom screens

Main components

  • ATMega 328
  • Crystal oscillator (16Mhz)
  • LiPo battery (240mAh)
  • Nokia 5110 LCD screen

Further reading

  • Project motivation – Why we built WatchDuino, what does it offer to the world, and some technical musings.

  • How to replicate – Components, libraries, and everything you need to build your own WatchDuino.

  • How to program – Hack on WatchDuino’s software to make your own apps and customizations.