Sensor Watch: a board swap for the classic Casio F-91W wristwatch
Sensor Watch: a board swap for the classic Casio F-91W wristwatch
Get Started Order at Crowd Supply
Sensor Watch is a board replacement for the classic Casio F‑91W wristwatch. It is powered by a Microchip SAM L22 microcontroller with built-in segment LCD controller. You can write your own programs for the watch using the provided watch library, program the watch over USB using the built-in UF2 bootloader, and then install the board in your existing watch case to run your own software on your wrist.

#### Smart ARM power
Sensor Watch is powered by the Microchip SAM L22, an ARM Cortex M0+ microcontroller with tons of powerful peripherals.
#### Long-lived battery
Sensor Watch sips single-digit microamperes of power, making this a watch you can wear all year on a single coin cell.
#### Timeless Timekeeping
A highly accurate 32.768 KHz crystal keeps accurate time — and displays it on the original F-91W LCD for a classic look and feel.
#### Light and sound
The LED backlight supports shades of red, green and yellow. With light soldering, you can also use the F-91W’s piezo buzzer.
#### Sensor Extensible
A 9-pin connector breaks out an I²C bus and five GPIO for SPI, UART or analog input, letting you add sensors to Sensor Watch.
#### Open Source
Fully open source hardware and software allow you to buy one or build your own — and remix the firmware to suit your taste.
Preorder at Crowd Supply!
#### Join the Sensor Watch Discord!
Chat with other Sensor Watch users and get help with your own Sensor Watch build.
#### Contributions welcome!
We do a Pull Request contributions workflow on GitHub. New users are always welcome!
#### Follow along on Twitter!
Get the absolute latest from the developer of Sensor Watch, plus other posts.
