MQTT protocol with Thingspeak using Micropython on ESP8266 and ESP32

Example code showing how to use the MQTT protocol with the Thingspeak cloud service [https://thingspeak.com]

• Publish data
• Subscribe to data
• Micropython
• ESP8266
• ESP32

Thingspeak configuration

1. Create a Thingspeak account https://thingspeak.com
2. Create a new Thingspeak channel (select New Channel on the My Channels page)
3. Find the following Thingspeak channel information
   • Channel ID (found at the top of every channel page)
   • User ID (found in Account-> My Profile)
   • Read API Key (found in the API Keys TAB)
   • Write API Key (found in the API Keys TAB)
   • MQTT API Key (found in Account-> My Profile)

Example code configuration

• The code is commented at various places with "ENTER_" indicating places where Thingspeak configuration parameters are needed

Limitations

• examples support only one field in the channel

Tested with Hardware

• Adafruit Feather HUZZAH ESP8266
• Adafruit Feather HUZZAH ESP32
• WeMos D1 Mini

Tested with Micropython Versions

• Micropython v1.9.3
• Micropython v1.9.4
• Micropython v1.10

Recommended Tools for Windows

• 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

Publishing data to ThingSpeak channels

Usage

1. Install the UMQTT Package (if needed) See section below Installing UMQTT Package
2. Configure code file publishThingspeak.py with ThingSpeak parameters
3. Copy the file publishThingspeak.py to your device, using ampy, rshell, webrepl

$ ampy -pCOMx -d1 put publishThingspeak.py main.py

4. Reset the board
5. Observe that data is being Published to the ThingSpeak channel at Thingspeak.com

Subscribing to ThingSpeak channels

Usage

1. Install the UMQTT Package (if needed) See section below Installing UMQTT Package
2. Configure code file subscribeThingspeak.py with ThingSpeak parameters
3. Copy the file subscribeThingspeak.py to your device, using ampy, rshell, webrepl

$ ampy -pCOMx -d1 put subscribeThingspeak.py main.py

4. Configure a 2nd device to publish the freeHeap data (see above)
5. Reset the board
6. Connect to the REPL with Putty (or simlar) to observe subscribed channel data being received (every 30s in the example code)

Installing UMQTT Package

The example code requires the MicroPython MQTT (UMQTT) Package. Some firmware releases have this package built-in, others don't.

Firmware Release	umqtt built-in?	GitHub Library
MicroPython 1.9.3 for ESP8266	Yes	n/a
MicroPython 1.9.4 for ESP8266	Yes	n/a
MicroPython 1.10 for ESP8266	Yes	n/a
MicroPython 1.9.4 for ESP32	No	Micropython lib
MicroPython 1.10 for ESP32	Yes	n/a

How to install the UMQTT package (if "No" is indicated in the table above)

1. Navigate to the GitHub library indicated in the table
2. Select the "Clone or download" button
3. Select "Download ZIP"
4. Extract the ZIP. Should see folder called "micropython-lib-master"
5. Two files need to be copied to the MicroPython filesystem
   • micropython-lib-master\umqtt.robust\umqtt\simple.py
   • micropython-lib-master\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

Validating the UMQTT package install

From the REPL (using Putty, etc) execute the following commands and observe similar output

>>> from umqtt.robust import MQTTClient

>>> dir(MQTTClient)
['reconnect', 'log', 'publish', '__module__', 'wait_msg', 'delay', '__qualname__', 'DELAY', 'DEBUG']

If you see this result you have successfully installed the umqtt package. 🎉 😌