Example code showing how to use the MQTT protocol with the Thingspeak cloud service [https://thingspeak.com]
- Publish data
- Subscribe to data
- Create a Thingspeak account https://thingspeak.com
- Create a new Thingspeak Channel (select New Channel on the My Channels page)
- the
Channel ID
is required for configuration (found at the top of every channel page)
- the
- Create a new MQTT Device by following instructions in https://www.mathworks.com/help/thingspeak/mqtt-basics.html
- when you create a new MQTT device it is important to record the three configuration parameters:
MQTT Client ID
MQTT Username
MQTT Password
(careful - you can only copy the password during the MQTT device creation step)
- when you create a new MQTT device it is important to record the three configuration parameters:
- The code includes variables with the form "ENTER_" indicating places where WiFi and Thingspeak configuration parameters are needed
- Adafruit Feather HUZZAH ESP8266
- Adafruit Feather HUZZAH ESP32
- WeMos D1 Mini
- Lolin D32
- Lolin D32 Pro
- Pyboard D (note: requires UMQTT library to be installed)
- Micropython v1.19.1
- Adafruit Ampy to copy files to the filesystem
- install version 1.0.3 or newer which has the -d option (use -d1 to avoid USB connection issues in Windows)
- Putty to interact with the REPL
- set Serial speed to 115200 and Flow control to None
- Configure code file publishThingspeak.py with WiFi and ThingSpeak configuration parameters
- Copy the file publishThingspeak.py to your device, using ampy, rshell, or webrepl
$ ampy -pCOMx -d1 put publishThingspeak.py main.py
- Reset the board
- Observe that data is being Published to the ThingSpeak channel at Thingspeak.com
- Configure code file subscribeThingspeak.py with ThingSpeak parameters
- Copy the file subscribeThingspeak.py to your device, using ampy, rshell, webrepl
$ ampy -pCOMx -d1 put subscribeThingspeak.py main.py
- Configure a 2nd device to publish the freeHeap data (see above)
- Reset the board
- Connect to the REPL with Putty (or simlar) to observe subscribed channel data being received (every 30s in the example code)
The example code requires the MicroPython MQTT (UMQTT) Package. Pyboard D firmware does not have this package built-in
- Navigate to [Micropython lib](https://github.com/micropython/micropython-lib
- Select the "Clone or download" button
- Select "Download ZIP"
- Extract the ZIP. Should see folder called "micropython-lib-master"
- Two files need to be copied to the MicroPython filesystem
- micropython-lib\micropython\umqtt.simple\umqtt\simple.py
- micropython-lib\micropython\umqtt.robust\umqtt\robust.py
Copy these two files to the MicroPython filesystem with the directory structure shown below.
boot.py
lib
|
umqtt
simple.py
robust.py
Example with Ampy:
>ampy -pCOM27 -d1 ls
boot.py
>ampy -pCOM27 -d1 mkdir lib
>ampy -pCOM27 -d1 mkdir lib/umqtt
>ampy -pCOM27 -d1 put simple.py lib/umqtt/simple.py
>ampy -pCOM27 -d1 put robust.py lib/umqtt/robust.py
>ampy -pCOM27 -d1 ls
boot.py
lib
>ampy -pCOM27 -d1 ls lib
umqtt
>ampy -pCOM27 -d1 ls lib/umqtt
simple.py
robust.py
From the REPL (using Putty, etc) execute the following commands and observe similar output
>>> from umqtt.robust import MQTTClient
>>> dir(MQTTClient)
['__class__', '__init__', '__module__', '__name__', '__qualname__', '__bases__', '__dict__', 'connect', 'delay', 'disconnect', 'log', 'DEBUG', 'DELAY', 'reconnect', 'publish', 'wait_msg', '_send_str', '_recv_len', 'set_callback', 'set_last_will', 'ping', 'subscribe', 'check_msg']
If you see this result you have successfully installed the umqtt package. 🎉 😌