Firmware for a remote control transceiver for outdoor roller blinds/shades/???. Runs on an ATmega328P (i.e. Arduino Nano or similar) and acts as a bidirectional bridge between radio and serial.
Serial protocol description is in main.c. It works the same in both directions. You'll probably also need to change the header in blinds.c. A Universal Radio Hacker project file and example captures are provided to assist with troubleshooting (the decoder to use is called "Long 1_3").