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50 lines
1.6 KiB
Markdown
50 lines
1.6 KiB
Markdown
---
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title: "MQTT"
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aliases:
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- tutorials/all/mqtt.html
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- tutorials/all/mqtt.md
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- chapter/tutorials/all/mqtt
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---
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MQTT is a lightweight messaging protocol that is ideal for sending small packets of data to and from IoT devices via WiFi.
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The broker used in this example is the [IO Adafruit](https://io.adafruit.com) platform, which is free and allows for tinkering with MQTT.
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Visit [IO Adafruit](https://io.adafruit.com) and create an account. You'll need to get hold of an API Key as well as your credentials. Visit this [guide](https://learn.adafruit.com/adafruit-io/mqtt-api) for more information about MQTT and how to use it with Adafruit's Broker.
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This example will send a message to a topic on the Adafruit MQTT broker and then also subscribe to the same topic, in order to show how to use the subscribe functionality.
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```python
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from mqtt import MQTTClient
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from network import WLAN
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import machine
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import time
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def sub_cb(topic, msg):
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print(msg)
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wlan = WLAN(mode=WLAN.STA)
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wlan.connect("yourwifinetwork", auth=(WLAN.WPA2, "wifipassword"), timeout=5000)
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while not wlan.isconnected():
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machine.idle()
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print("Connected to WiFi\n")
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client = MQTTClient("device_id", "io.adafruit.com",user="your_username", password="your_api_key", port=1883)
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client.set_callback(sub_cb)
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client.connect()
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client.subscribe(topic="youraccount/feeds/lights")
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while True:
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print("Sending ON")
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client.publish(topic="youraccount/feeds/lights", msg="ON")
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time.sleep(1)
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print("Sending OFF")
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client.publish(topic="youraccount/feeds/lights", msg="OFF")
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client.check_msg()
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time.sleep(1)
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```
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