While Wi-Fi and Bluetooth are useful for automation, wireless control via infrared remotes is nearly ubiquitous in stock consumer electronics. There’s no setup, you simply point the device at your TV, stereo, or other appliance, push the right button, and it turns on. While simple to use, there’s a lot going on behind the scenes, as David Johnson-Davies explains on his Technoblogy post about how he built an IR decoder.
His device, which works with a variety of different protocols, uses a Vishay TSOP38238 IR receiver to get remote signals, then pipes this info to an ATtiny85 chip. The ATtiny then decodes the signal, and sends the results to a 128x32 OLED display. All of this takes place in a nice compact package that fits onto a tiny breadboard.
Program-wise, the ATtiny85 first determines what type of remote is being used based on how the sequence of pulses starts. Depending on the type of protocol in use, it then decodes the binary signal, broken up into address and command bits that are transmitted in different formats. While you might choose to duplicate this project, the writeup gives a great explanation of how IR signaling works — useful if you’re seeking to understand this tech for your own project.