• 物聨網平台(以MQTT為例)

溫濕度計發送訊息

• 講義

• 使用樹莓派連接DHT溫濕度計，並使用Python程式將感測值使用MQTT技術發送訊息到主機端。

  【硬體接線】

  

  【程式碼】

  import paho.mqtt.client as mqtt
  import Adafruit_DHT
  import time
  
  SENSOR = Adafruit_DHT.DHT11
  PIN = 4
  
  TOPIC = "sensor/temperature"
  TOPIC2 = "sensor/humidity"
  
  # 建立 MQTT client
  client = mqtt.Client()
  
  # 連線到 Mosquitto broker
  client.connect("192.168.1.116", 1883, 60)
  
  # 啟動 loop，維持連線
  client.loop_start()
  
  try:
      while True:
          humidity, temperature = Adafruit_DHT.read_retry(SENSOR, PIN)
          if temperature is not None:
              msg = f"{temperature:.1f}"
              print(f"Publish {TOPIC}: {msg} ")
              client.publish(TOPIC, msg)
          if humidity is not None:
              msg2 = f"{humidity:.1f}"
              print(f"Publish {TOPIC2}: {msg2} ")
              client.publish(TOPIC2, msg2)
          else:
              print("can't read data")
          time.sleep(60)
  except KeyboarInterrupt:
      print("end")
      client.loop_stop()
      client.disconnect()