Python Script für den INSTAR MQTT Alarmserver

Auf dem Raspberry Pi:

# python3.6
import random
import json
import time
import RPi.GPIO as GPIO
from paho.mqtt import client as mqtt_client

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup(18,GPIO.OUT)
GPIO.output(18,0)

broker = '192.168.66.20'
port = 1883
topic = "instar/+/status/alarm/triggered"

# generate client ID with pub prefix randomly

client_id = f'python-mqtt-{random.randint(0, 100)}'

def connect_mqtt() -> mqtt_client:
    def on_connect(client, userdata, flags, rc):
        if rc == 0:
            print("Connected to MQTT Broker!")
        else:
            print("Failed to connect, return code %d\n", rc)
           
    client = mqtt_client.Client(client_id)
    client.on_connect = on_connect
    client.connect(broker, port)
    return client

def subscribe(client: mqtt_client):
    def on_message(client, userdata, msg):
        #print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")
        t = (msg.payload.decode())
        #print(t)
        g = json.loads(t)
        #print(g)
        #print("Alarmbereich : " + str(g["val"]))
        h = (g["val"])
        print(h)
        i = int(h)     # Umwandlung in INT
        if i > 0:
            GPIO.output(18,1)
            time.sleep(2)                      # 2 Sekunden Impuls für Alarmanlage
            GPIO.output(18,0)
        else:
            GPIO.output(18,0)
            
               
    client.subscribe(topic)
    client.on_message = on_message
       
def run():
    client = connect_mqtt()
    subscribe(client)
    client.loop_forever()
   
if __name__ == '__main__':
    run()

Das Skript rufe ich beim Systemstart auf:

sudo crontab -e

darin: @reboot sleep 15 && /usr/bin/python3 /home/pi/rkk.py &