The Type 2 simulator uses Magneto-Resistive Sensor Modules, based on work by Aidan Hedley, which have no moving or optical parts. Schematics, PCB design and manufacturing files are and full documentation are available on GitHub. The sensors connect to to the Simulator Interface in daisy chains of up to four sensors, using standard RJ45 network cables, and chains of up to 20m have been tested. The sensors are designed to fit into a small Really Useful box.
The construction and configuration of the simulator are comprehensively documented on GitHub.
Completed Magneto-Resistive Sensor Module