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This article mainly shows you "how raspberry pie realizes mqtt communication". The content is easy to understand and clear. I hope it can help you solve your doubts. Let me lead you to study and learn this article "how raspberry pie realizes mqtt communication".

1 、 sudo pip install paho-mqtt

2. Python code

#-*-coding: utf-8-*-

Import paho.mqtt.client as mqtt

# import RPi.GPIO as GPIO

Import json,sys

# if sys.version_info < (3,0):

# reload (sys)

# sys.setdefaultencoding ('utf8')

# else:

# raw_input = input

Username='public'

Password='123456'

Hostname='xxx.xxx.xxx.xxx'

# BCM GPIO number

Pins = [17, 18, 27, 22, 23, 24, 25, 4]

Def gpio_setup ():

# using BCM numbering

GPIO.setmode (GPIO.BCM)

# set all GPIO to output state and output low level

For pin in pins:

GPIO.setup (pin, GPIO.OUT)

GPIO.output (pin, GPIO.LOW)

Def gpio_destroy ():

For pin in pins:

GPIO.output (pin, GPIO.LOW)

GPIO.setup (pin, GPIO.IN)

# callback function for successful connection

Def on_connect (client, userdata, flags, rc):

Print ("Connected with result code" + str (rc))

# subscribe to gpio topics after the connection is completed

Client.subscribe ("gpio")

# message push callback function .decode ("utf-8")

Def on_message (client, userdata, msg):

Print (msg.topic+ "" + str (msg.payload))

# get pin and value in the load

# gpio = json.loads (str (msg.payload))

# if gpio ['pin'] in pins:

# if gpio ['value'] = = 0:

# GPIO.output (gpio ['pin'], GPIO.LOW)

# else:

# GPIO.output (gpio ['pin'], GPIO.HIGH)

If _ _ name__ = ='_ _ main__':

Client = mqtt.Client ()

Client.on_connect = on_connect

Client.on_message = on_message

# gpio_setup ()

Try:

# Please change the IP address and account password authentication of the MQTT proxy server according to the actual situation

# client.username_pw_set (username,password)

Client.connect ("xxx.xxx.xxx.xxx", 1883, 60)

Client.loop_forever ()

Except KeyboardInterrupt:

Client.disconnect ()

Gpio_destroy ()

Send data as {"pin": 12, "value": 1}

These are all the contents of the article "how Raspberry pie achieves mqtt Communications". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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