MicroPython is a lean and efficient implementation of the Python 3 programming language that includes a small subset of the Python standard library and is optimised to run on microcontrollers and in constrained environments.
To showcase our library, we've put together a little project to enable remote control over a small LED lamp in our office. We used Pycom's FiPy board, but the code should seamlessly run on Pycom's other boards as well. However, there may be some differences regarding what pins should be used on different boards, so please refer to your board's pinout diagram.
Before beginning, make sure that your board is programmed correctly by getting the latest firmware and that you have the Pymakr plugin installed in Atom or in VS Code. Apart from Pymakr, we've found that you can also use ampy to check how your code runs on the board, and mpfshell to manage files on your board and enter REPL mode as well. For any additional information, visit Pycom's docs page.
So what needs to be done? You need to clone WolkConnect-MicroPython in order to have access to the wolk.py module, which you will need to copy onto the board later.
git clone https://github.com/Wolkabout/WolkConnect-MicroPython.git
You will also need to copy Pycom's implementation of an MQTT client that is a dependency for WolkConnect-MicroPython and can be found here: mqtt.py. There is also a copy of this module in the attachments under the same name.
Besides those two modules, there are only two additional files: boot.py - first script to be run on the device that will set up the board, and main.py - where the actual control over the LED lamp will take place. Both of these files can be found in the attachments of this post.
Before you start copying the files over to the board, you need to make some changes to the main.py, namely editing the WiFi credentials on line 21
# WiFi WIFI_SSID = "WIFI_SSID" WIFI_AUTH = WLAN.WPA2 # WEP, WPA, WPA2, WPA2_ENT WIFI_PASSWORD = "WIFI_PASSWORD"
and entering the credentials you get from WolkAbout IoT Platform when creating a device.
To get these credentials, you need to create a device first by using a device template. The device template for this project, "Smart light-manifest.json", is available in the attachments, so create a copy of it. Log in to or create your account on WolkAbout IoT Platform and navigate to the Devices section.
Select the Device templates tab, and then press the + sign, and select the Upload option navigating to your local copy of the device template.
Now that a device template is available, you can create a device from it by clicking Create device.
The following form has the Smart light device template pre-selected, so simply press Next step.
Here, you need to give your device a name and tick the checkbox for Create semantic group for this device (this is necessary for creating widgets on your dashboard later on).
Then, press Save and the form with device credentials will be displayed. Store these streams of information however you want and then enter them into main.py on line 17:
wolk.DEVICE_KEY = "device_key" wolk.DEVICE_PASSWORD = "some_password"
Additionally, enter the reference used for the Switch actuator of our device.
wolk.ACTUATOR_REFERENCES = ["SW"]
We used pin P3 on our FiPy board to connect the Relay click, but if you happen to use another pin, edit line 27:
LIGHT_SWITCH = Pin("P3", mode=Pin.OUT)
and these are all the changes that need to be made to the project.
Now, you can connect the board by using USB and copy over the required files so that they conform to the following structure:
> flash - boot.py - main.py > lib -wolk.py -mqtt.py
After connecting the board to your PC, you will need to get the name of the port. On Linux, you can run
dmesg | grep tty and on Windows go to Device Manager and find the name listed under Ports. You will need this to set up your Pymakr project or for connecting with mpfshell.
If you use the Pymakr plugin, create a directory, open it as a project in Atom or VS Code and then copy boot.py and main.py into this directory. Make a directory named lib and then copy wolk.py and mqtt.py to it. Now you can synchronise the project by pressing the Sync icon from the console.
Using mpfshell, copying files can be done by navigating to a local folder that contains all the necessary files and running
mpfshell -c "open ttyUSB0"
You will be in the flash directory, so here run
put boot.py and
After that, run
cd lib and then
put wolk.py and finally
Once that all the files are in place you can enter REPL mode by entering
repl. Now you can perform a soft-reboot of the device by pressing CTRL+D (exit REPL mode with CTRL+] ). The board will run boot.py that will start main.py and duplicate its output to the terminal so you can make sure that the device can connect to the WiFi network. At this point, the onboard LED should glow a faint red, signalling that the light switch is in the off state.
Finally, to change the state of the light switch, you need to create a dashboard on WolkAbout IoT Platform and place a widget for controlling the switch. To do so, navigate to the Dashboards section, press + and enter a name for the dashboard. Then you can add a widget to your dashboard by pressing Add widget
and then select Switch from your device and click Save.
Now, if your board is powered on, you should see the current that of the switch
and you can change its state by clicking on the knob and clicking the check sign.
The device will receive the command and turn on the light switch!