network_relay.py

#!/usr/bin/python3
# Send UDP messages as UTF-8 char messages like '<channel> <state>' -- sends back '<channel> <state> <code>\r\n' where code is 1 if successful, -1 if state invalid, -2 if channel invalid. 
#  channel: Should be '1', '2', '3', '4', '5', '6', '7', or '8'
#  state: Should be '0' (off) or '1' (on)
import RPi.GPIO as GPIO
import socket
import time

UDP_RELAY_IP = "0.0.0.0"
UDP_RELAY_PORT = 7010                   # Access this UDP port for byte messages
PINOUT = [5, 6, 13, 16, 19 ,20, 21, 26] # BCM pins for Relay Hat Module

def initializeRelayPins():
  GPIO.setmode(GPIO.BCM)
  GPIO.setwarnings(False)
  for pin in PINOUT:
    GPIO.setup(pin, GPIO.OUT)
    GPIO.output(pin, False)

def myNetworkInterface(listener_ip: str = UDP_RELAY_IP, listener_port: int = UDP_RELAY_PORT):
  sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  sock.bind((listener_ip, listener_port))
  print(f"Listening for UDP messages on {listener_ip}:{listener_port}...")
  while True:
    data, addr = sock.recvfrom(8) # Buffer size is 8 bytes
    message = data.decode('utf-8').strip()
    print(f"Received message: {message} from {addr}")
    
    try:
      channel, state = message.split()
      channel = int(channel)-1
      confirmation_base = "f"{channel+1} {state}"
      if 0 <= channel < len(PINOUT):
        pin_number = PINOUT[channel]
        if state == '1':
          GPIO.output(pin_number, True)
          confirmation_state = 1
        elif state == '0':
          GPIO.output(pin_number, False)
          confirmation_state = 1
        else:
          print(f"Unknown state: {state}")
          confirmation_state = -1
      else:
        print(f"Invalid channel number: {channel + 1}")
        confirmation_state = -2
      confirmation_message = f"{confirmation_base} {confirmation_state}\r\n"
      sock.sendto(confirmation_message.encode('utf-8'),addr)
    except Exception as e: 
      print(f"Error processing message: {e}")
  
  if __name__ == "__main__":
    initializeRelayPins()
    try:
      myNetworkInterface()
    except KeyboardInterrupt:
      for pin in PINOUT:
        GPIO.output(pin,False)
      GPIO.cleanup()
    except Exception as e:
      print(f"An error occurred: {e}")
      for pin in PINOUT:
        GPIO.output(pin,False)
      GPIO.cleanup()