Sensor Watch is a modern hardware drop-in for the classic Casio watch. It takes an iconic 30-year-old design from a golden age of digital watches, and pairs it with a modern, powerful microcontroller. This small circuit board, less than an inch in diameter, replaces the original quartz movement in a Casio F-91W or A158W watch to put the capabilities of an ultra-low-power ARM Cortex M0+ microcontroller on your wrist.
Sensor Watch Pro is the most advanced version of Sensor Watch yet. In addition to its 9-pin connector for interfacing with external sensor boards (like the included accelerometer board add-on), it adds an RGB LED, an infrared light sensor, a voltage boost for the piezo buzzer for extra volume, and a soldering-free installation experience. It’s also, as a watch, extremely accurate thanks to its software-defined temperature compensation; with fine tuning, Sensor Watch Pro can drift less than a second per year.
Sensor Watch is not like most smart watches. It makes a different set of engineering tradeoffs, to achieve a different set of goals: