1  import time
  2  import board
  3  import busio
  4  import digitalio
  5  from adafruit_fona.adafruit_fona import FONA
  6  import adafruit_fona.adafruit_fona_network as network
  7  import adafruit_fona.adafruit_fona_socket as socket
  8  
  9  import adafruit_minimqtt.adafruit_minimqtt as MQTT
 10  
 11  ### Cellular ###
 12  
 13  # Get cellular details and more from a secrets.py file
 14  try:
 15      from secrets import secrets
 16  except ImportError:
 17      print("Cellular secrets are kept in secrets.py, please add them there!")
 18      raise
 19  
 20  # Create a serial connection for the FONA connection
 21  uart = busio.UART(board.TX, board.RX)
 22  rst = digitalio.DigitalInOut(board.D4)
 23  # Initialize FONA
 24  fona = FONA(uart, rst)
 25  
 26  ### Topic Setup ###
 27  
 28  # MQTT Topic
 29  # Use this topic if you'd like to connect to a standard MQTT broker
 30  mqtt_topic = "test/topic"
 31  
 32  # Adafruit IO-style Topic
 33  # Use this topic if you'd like to connect to io.adafruit.com
 34  # mqtt_topic = 'aio_user/feeds/temperature'
 35  
 36  ### Code ###
 37  
 38  # Define callback methods which are called when events occur
 39  # pylint: disable=unused-argument, redefined-outer-name
 40  def connect(client, userdata, flags, rc):
 41      # This function will be called when the client is connected
 42      # successfully to the broker.
 43      print("Connected to MQTT Broker!")
 44      print("Flags: {0}\n RC: {1}".format(flags, rc))
 45  
 46  
 47  def disconnect(client, userdata, rc):
 48      # This method is called when the client disconnects
 49      # from the broker.
 50      print("Disconnected from MQTT Broker!")
 51  
 52  
 53  def subscribe(client, userdata, topic, granted_qos):
 54      # This method is called when the client subscribes to a new feed.
 55      print("Subscribed to {0} with QOS level {1}".format(topic, granted_qos))
 56  
 57  
 58  def unsubscribe(client, userdata, topic, pid):
 59      # This method is called when the client unsubscribes from a feed.
 60      print("Unsubscribed from {0} with PID {1}".format(topic, pid))
 61  
 62  
 63  def publish(client, userdata, topic, pid):
 64      # This method is called when the client publishes data to a feed.
 65      print("Published to {0} with PID {1}".format(topic, pid))
 66  
 67  
 68  # Initialize cellular data network
 69  network = network.CELLULAR(
 70      fona, (secrets["apn"], secrets["apn_username"], secrets["apn_password"])
 71  )
 72  
 73  while not network.is_attached:
 74      print("Attaching to network...")
 75      time.sleep(0.5)
 76  print("Attached!")
 77  
 78  while not network.is_connected:
 79      print("Connecting to network...")
 80      network.connect()
 81      time.sleep(0.5)
 82  print("Network Connected!")
 83  
 84  # Initialize MQTT interface with the cellular interface
 85  MQTT.set_socket(socket, fona)
 86  
 87  # Set up a MiniMQTT Client
 88  client = MQTT.MQTT(
 89      broker=secrets["broker"],
 90      username=secrets["user"],
 91      password=secrets["pass"],
 92      is_ssl=False,
 93  )
 94  
 95  # Connect callback handlers to client
 96  client.on_connect = connect
 97  client.on_disconnect = disconnect
 98  client.on_subscribe = subscribe
 99  client.on_unsubscribe = unsubscribe
100  client.on_publish = publish
101  
102  print("Attempting to connect to %s" % client.broker)
103  client.connect()
104  
105  print("Subscribing to %s" % mqtt_topic)
106  client.subscribe(mqtt_topic)
107  
108  print("Publishing to %s" % mqtt_topic)
109  client.publish(mqtt_topic, "Hello Broker!")
110  
111  print("Unsubscribing from %s" % mqtt_topic)
112  client.unsubscribe(mqtt_topic)
113  
114  print("Disconnecting from %s" % client.broker)
115  client.disconnect()