Laser barrier modules

Optical robot detectors for use on race tracks and other projects

What it's about

This code is intended to operate up to four lasers and photodetectors which will function as optical barriers to detect the presence of a robot, when the beam is interrupted. The beams are modulated at around 1kHz, to allow for some robustness: it is not possible to fool the module by firing a plain laser pointer into it, and the hardware can easily be designed to incorporate a high-pass filter to remove ambient light.

Input / Output

The module takes one input (Enable). Up to four lasers (or IR LEDs) and four photodetectors can be connected at any time. The module outputs four logic signals, corresponding to the state of each beam.