Reading an infrared (IR) receiver with Python on GNU/Linux

README.md

Reading an infrared (IR) receiver with Python on GNU/Linux

Many development boards incorporate an infrared receiver, such as Orange PI, Bananapi, Libre computer, Pine64, etc.

This manual explains how to configure the infrared receiver in Linux and shows an example of how to read the infrared codes emitted by a remote control.

Configuration

Show all input devices:

cat /proc/bus/input/devices

Add all protocols (add this line to the /etc/rc.local to start at boot):

ir-keytable -c -p all

Show activated IR protocols:

cat /sys/class/rc/rc0/protocols

Testing input device:

evtest /dev/input/by-path/*.ir-event

ir-linux.py

#!/usr/bin/env python3

import struct
import time
import sys

DEV_EVENT_IR = "/dev/input/event1"

"""
struct input_event {
	struct timeval time;  {long int, long int}
	unsigned short type;
	unsigned short code;
	unsigned int value;
};
"""

FORMAT = 'llHHI'  # long int, long int, unsigned short, unsigned short, unsigned int
EVENT_SIZE = struct.calcsize(FORMAT)


def main():
	fd_ir = open(DEV_EVENT_IR, "rb")

	try:
		while True:

			event = fd_ir.read(EVENT_SIZE)
			(tv_sec, tv_usec, evtype, code, value) = struct.unpack(FORMAT, event)

			if evtype != 0 or code != 0 or value != 0:
				print("{}.{}: event type {}, code {}, value {}".format(tv_sec, tv_usec, evtype, code, value))

			else:
				# Events with code, type and value == 0 are "separator" events
				print("===========================================")
	
	except KeyboardInterrupt:
		fd_ir.close()
		print("\n\nClose device.")
	
	print("Exit.")
	sys.exit(0)


if __name__ == "__main__":
	main()