Timex Datalink Notebook Adapter emulator for Arduino

This project emulates the Timex Datalink Notebook Adapter for early Timex Datalink watches in Arduino! It is 100% compatible with the original Notebook Adapter, and works with vintage and modern computer hardware.

This project is not dependent on any specific Arduino board, although it is designed with the Teensy LC in mind. The Teensy LC has USB serial and an onboard LED, so the board can be used as-is without any external components:

How does it work?

The early Datalink watches receives data over light, and the original intent was to take advantage of a flashing electron beam on a CRT. Timex also offered a Notebook Adapter accessory intended for mobile users at the time, which replicates the data sent from a CRT using a single LED:

The Notebook Adapter is a serial device with a proprietary protocol that was reverse-engineered for this project. With the Arduino device present, the original Timex Datalink software can be configured to use the Notebook Adapter and send data to your watch: