Initial Release

bme280-homie.py

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+#!/usr/bin/python3
+import board, busio
+import adafruit_bme280
+import paho.mqtt.client as mqtt
+import time, ssl, systemd.daemon
+
+# set the variables
+broker='FQDN / IP Adresse'
+port=8883
+mqttclientid = "clientid-bme280-homie"
+clientid = "clientid-bme280"
+clientname = "Clientname BME280 Sensor"
+nodes="bme280"
+username='mosquitto'
+password='password'
+insecure=True
+qos=1
+retain_message=True
+# Retry to connect to mqtt broker
+mqttretry = 5
+# how often should be a publish to MQTT (in Seconds)
+publishtime=15
+
+# do the stuff
+### Functions
+def publish(topic, payload):
+  client.publish("homie/" + clientid + "/" + topic,payload,qos,retain_message)
+
+def on_connect(client, userdata, flags, rc):
+  print("MQTT Connection established, Returned code=",rc)
+  # homie client config
+  publish("$state","init")
+  publish("$homie","4.0")
+  publish("$name",clientname)
+  publish("$nodes",nodes)
+  # homie node config
+  publish(nodes + "/$name","BME280 Sensor")
+  publish(nodes + "/$properties","temperature,humidity,pressure")
+  publish(nodes + "/temperature/$name","Temperature")
+  publish(nodes + "/temperature/$unit","°C")
+  publish(nodes + "/temperature/$datatype","float")
+  publish(nodes + "/temperature/$settable","false")
+  publish(nodes + "/humidity/$name","Humidity")
+  publish(nodes + "/humidity/$unit","%")
+  publish(nodes + "/humidity/$datatype","float")
+  publish(nodes + "/humidity/$settable","false")
+  publish(nodes + "/pressure/$name","Pressure")
+  publish(nodes + "/pressure/$unit","hPa")
+  publish(nodes + "/pressure/$datatype","float")
+  publish(nodes + "/pressure/$settable","false")
+  # homie stae ready
+  publish("$state","ready")
+
+def on_disconnect(client, userdata, rc):
+  print("MQTT Connection disconnected, Returned code=",rc)
+
+# running the Script
+# define BME280 Sensor
+i2c = busio.I2C(board.SCL, board.SDA)
+bme280 = adafruit_bme280.Adafruit_BME280_I2C(i2c, address=0x76)
+# change this to match the location's pressure (hPa) at sea level
+#bme280.sea_level_pressure = 1010
+bme280.mode = adafruit_bme280.MODE_NORMAL
+time.sleep(1)
+
+#MQTT Connection
+mqttattempts = 0
+while mqttattempts < mqttretry:
+  try:
+    client=mqtt.Client(mqttclientid)
+    client.username_pw_set(username, password)
+    client.tls_set(cert_reqs=ssl.CERT_NONE) #no client certificate needed
+    client.tls_insecure_set(insecure)
+    client.will_set("homie/" + clientid + "/$state","lost",qos,retain_message)
+    client.connect(broker, port)
+    client.loop_start()
+    mqttattempts = mqttretry
+  except :
+    print("Could not establish MQTT Connection! Try again " + str(mqttretry - mqttattempts) + "x times")
+    mqttattempts += 1
+    if mqttattempts == mqttretry:
+      print("Could not connect to MQTT Broker! exit...")
+      exit (0)
+    time.sleep(5)
+
+# Tell systemd that our service is ready
+systemd.daemon.notify('READY=1')
+
+client.on_connect = on_connect
+client.on_disconnect = on_disconnect
+
+# finaly the loop
+while True:
+  try:
+    publish(nodes + "/temperature","{:.2f}".format(bme280.temperature))
+    publish(nodes + "/humidity","{:.2f}".format(bme280.humidity))
+    publish(nodes + "/pressure","{:.2f}".format(bme280.pressure))
+    time.sleep(publishtime)
+
+  except KeyboardInterrupt:
+    print("Goodbye!")
+    # At least close MQTT Connection
+    publish("$state","disconnected")
+    time.sleep(1)
+    client.disconnect()
+    client.loop_stop()
+    exit (0)
+
+  except :
+    print("An Error accured ... ")
+    time.sleep(3)
+    continue
+
+# At least close MQTT Connection
+print("Script stopped")
+publish("$state","disconnected")
+time.sleep(1)
+client.disconnect()
+client.loop_stop()

bme280_homie.service

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+# systemd unit file for the Python BME280 Service
+[Unit]
+
+# Human readable name of the unit
+Description=BME280 MQTT Homie Service
+
+# Starting after System is online and docker is running
+# Only needed if MQTT is used
+Wants=network-online.target
+After=network-online.target
+#After=docker.service
+#After=docker.socket
+
+[Service]
+
+# Command to execute when the service is started
+ExecStart=/usr/bin/python3 /usr/local/sbin/bme280-homie.py
+
+# Disable Python's buffering of STDOUT and STDERR, so that output from the
+# service shows up immediately in systemd's logs
+Environment=PYTHONUNBUFFERED=1
+
+# Automatically restart the service if it crashes
+Restart=on-failure
+
+# Our service will notify systemd once it is up and running
+Type=notify
+
+# Use a dedicated user to run our service
+User=root
+
+# Send CTRL+C tot python Script to terminate it clean
+KillSignal=SIGINT
+
+[Install]
+
+# Tell systemd to automatically start this service when the system boots
+# (assuming the service is enabled)
+WantedBy=default.target