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 ...

[mircemk] shows how to create a simple non-contact proximity sensor using little more than an Arduino Nano board, and a convenient software library intended to measure the value of capacitors. The ...

Measuring the speed of a rotating object is a common requirement. Knowing the speed of table and ceiling fans, as well as kitchen appliances such as mixers ...