This explains how to use a modulated infrared LED and IR detector module for simple proximity sensing.
The PDF and related Arduino code were part of a presentation to the Nashua Robot Builders. The PDF was meant as a supplement to the talk, so some of the pages may seem sparse.
Requires Timer One library (https://github.com/PaulStoffregen/TimerOne).
If you decide to experiment with this library anyways, feel free to report issues, etc., but don't expect any level of support.
Thanks for your understanding!
--Jay
Copyright (c) 2017 Jay Francis. Licensed under the MIT license.