I recently had to build an infrared close proximity sensor that could tell if something was dropped in a parcel delivery drop box. After some searching, I ended up using a microcontroller and a piece ...

Photoelectric sensors detect objects and surface changes using variations in optical properties. Each sensor includes a light emitter and a receiver, with most relying on infrared light. In optical ...

Some readers may recall building a line-following robot during their school days. Involving some IR LEDs, perhaps a bit of LEGO, and plenty of trial-and-error, it was fun on a tiny scale. Now imagine ...