Hacking a Casio F91W digital watch (Bluetooth and OLED display)
The F91 Kepler project aims to redesign the classic Casio F91W watch by incorporating modern technology. It features an OLED display and Bluetooth capabilities, while retaining the original case. The project is currently in an unfinished state, with plans for further improvements and community involvement.
- ▪The F91 Kepler is a complete redesign of the Casio F91W watch.
- ▪It includes an OLED display and a Bluetooth capable microcontroller.
- ▪The project is currently incomplete, with a focus on enhancing software and functionality.
Opening excerpt (first ~120 words) tap to expand
F91 Kepler 8/8/25 - This project hasn't been active for a while, but I have kept it around for anyone interested in it or wants to draw inspiration from it. I have moved it from its original repo since I use GitHub more these days. The F91 Kepler is complete redesign of the classic Casio F91W watch. This project completely replaces the original internals of the watch only keeping the original case and adding an OLED display and a bluetooth capable MCU. This repo contains all the firmware, hardware, and completely unfinished software (phone app) ;). As of 7/18/22 the current state of the project is: Bluetooth capable and supports several calls. Only operates through bluetooth diagnostic apps such as nRF Connect. Full screen notifications for calls/texts. Notifications bar.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at GitHub.