Arduino PS2 to bus mouse adapter

Allows the use of a PS2 mouse (or USB mouse operating in PS2 compatibility mode) on systems with a bus mouse (quadrature) interface.

This sketch is based on an article by ezContents, with the following changes:

• The mouse is power-cycled during the initialisation phase, which fixes USB mice hanging at start-up.
• The initialisation phase is retried repeatedly until successful.
• More accurate translation of PS2 mouse position changes to bus mouse signals for better cursor movement.

Building

Copy the contents of the libraries directory to your user's Arduino libraries directory (usually ~/Arduino/libraries), then verify/upload the sketch using the Arduino IDE.

Notes

This sketch was tested on an Arduino Nano, with a Genius USB optical mouse and Acorn Archimedes A3000 computer. It should work with any system that requires quadrature-encoded mouse signals (usually a 9-pin mini DIN connector).

The power-cycling feature is optional, and enabled by connecting the PS2/USB mouse +5V line to pin 12 of the Arduino (instead of the +5V pin of the Arduino). Note that the Arduino digital pins can only source around 40mA of current, so the mouse must draw less than that or a transistor buffer will be required.