I'm looking for a way to transfer some 2-3 different bits from a moving part of mechanism to the microcontroller. The basic, "ugly" solution is through rubbing metal elements, but I'm worried this may introduce serious noise. What chips (IR, radio, other) could replace some 20 centimeters of 2- or 3-wire line?
(transfer rate about 3kbit/s/channel, less if sending asynchronously - on value change)

Most of solutions I had found on the forum are about interfacing the µC with some "smart device" like a computer, usually with the µC sending data or full duplex communication, but what I mean is gathering data from a simple endpoint sensor.