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 ...

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 ...

Unlike infrared optical sensors that use an LED transmitter and IR receiver, the PIR emits nothing. As its “passive” name suggests, it responds only to infrared energy radiated by the object being ...