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 ...

[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 … ...

While there are a couple of open-source brushless drivers already available, [neuromancer2701] created his own brushless motor controller on an Arduino shield.