Ever since the earliest days of telegraphy, electrical communication has been possible over a single wire. Today the 1-Wire Bus and similar protocols function using just one conductor, without the need for an additional clock line. Infrared (IR) remote controls operate on similar principles. In this session we get to grips with temperature and humidity sensors among other things, and in particular with the IR Transmitter and Receiver in Elektor’s 35 Sensors Kit.