I recently had to build an infrared close proximity sensor that could tell if something was dropped in a parcel delivery drop box. ... Here is the diagram of my Arduino infrared close proximity sensor ...

We’d seen it done with buttons, switches, gestures, capacitive touch, and IR remote, but never like this. [electron_plumber] made an LED that can be blown out like a candle, and amazingly it … ...

[Michael Gerstenmayer] has been very successful in developing a biofeedback system. He’s based the build around an Arduino and started adding different chunks to the project to develop a full… ...