NTE30116 Tinted Blue 5mm Infrared LED Emitter (940nm) SM0038 Photo Module for PCM Remote Control System (38kHz) The principle of this setup is somewhat simple and self-explanatory. In this circuit, ...

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 ...