# joeycastillo/Sensor-Watch

A board replacement for the classic Casio F-91W wristwatch

Repository: https://github.com/joeycastillo/Sensor-Watch
Canonical: https://ross.abutalabs.com/products/sensor-watch
Language: C
License: NOASSERTION
License Family: other
Last push: 2026-04-08T04:16:51+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 76, release rhythm 35, longevity 100
- inputs: {"age_days": 1971, "days_push": 147, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2054, forks 309 (observed 2026-08-28T04:06:09.767091+00:00)

## What it is
Sensor Watch is an open-source replacement main board for the classic Casio F-91W wristwatch, built around a Microchip SAM L22 ARM Cortex-M0+ microcontroller with a segment LCD controller. The repository provides a C watch library and UF2 bootloader workflow so users can write, flash, and run their own custom watch firmware and sensor boards.

## Use cases
- write custom firmware for a Casio F-91W watch
- build a programmable smartwatch with my own sensors
- replace the F-91W board with an open hardware alternative
- learn embedded C programming on a wearable device
- add custom sensors to a wristwatch via I2C or SPI
- flash watch apps over USB with a UF2 bootloader

## When to choose
- you own a Casio F-91W and want to run your own software on it
- you want a low-power, hackable wearable platform with a segment LCD
- you want to experiment with custom sensor boards over a flexible connector

## When to avoid
- you need a full-color display or touch interface
- you want a ready-made consumer smartwatch with app store support
- you are not comfortable with soldering or opening a watch case

## Facets
- artifact type: library
- maturity: active
- function: embedded, sdk, graphics
- domain: embedded-systems, hardware, developer-tools
- platform: embedded, c, cpp
- tags: casio-f-91w, wearable, microcontroller, firmware, saml22, open-hardware

## Member repositories
- joeycastillo/Sensor-Watch (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:09.767091+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:57:18.077884+00:00, confidence not recorded.
  - readme: https://github.com/joeycastillo/Sensor-Watch (fetched 2026-08-28T04:06:09.767091+00:00, sha 998b0ccd7253)
- Data as of 2026-08-30T08:39:29.467469+00:00.