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 ...

We’ve all been there. Your current project has hit a wall, or the next step will take days to complete, and you need something to do in the meantime. So you start a project that you envision will fit ...

A typical reflective object sensor consists of an infrared light emitter diode (IRED) and an NPN silicon phototransistor mounted side-by-side on parallel axes in a compact black plastic housing. The ...

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 ...