Infrared (IR) communication technologies are probably one of the most influential, yet also one of the least flashiest. The fact that IR communication tends to be highly directional and often limited to low data rate leads many people to scoff at it, deeming it barely worthy of more than making TV remotes work, perhaps along with some unloved industrial gear like the IR interface of electrical meters.
This is a shame, because TV remotes are a good example of why sometimes you want something that is directional, and anyone who has battled with Bluetooth pairing can attest to the value of things simply working by pointing it at the device. IR protocols also have the advantage of inherent privacy protection as walls and other obstacles will block the signal, unlike that of an exploitable Bluetooth device which happily advertises to your neighbors and passersby.
For reasons like the above – as well as their simplicity and hackability – IR protocols are worthy of a detailed look.
Remote Control
Naturally, one of the oldest uses of consumer IR protocols is that of the venerable IR remote control. Initially TVs used wired and ultrasonic remote controls, with the latter using simple ultrasonic tones to transfer a command, but with IR protocols and the advent of cheap MCUs it became possible to create extensive communication protocols. Of these the NEC, Sony IR (SIRC) and Philips protocols are probably the most well-known and most used.
