Learn More about control.py

In order to better understand the projects that follow, let’s take a look at the official sample code provided by Cloud4RPi.


Please complete the previous section Quick Guide on Cloud4RPi before viewing this section.

Open the control.py file.

cd cloud4rpi-raspberrypi-python
sudo nano control.py

Cloud4RPi will set a device token for each one, and you need to fill in the variable DEVICE_TOKEN with the correct device token in order to connect to the corresponding device.

DEVICE_TOKEN = '556UfPaRw6r6rDKYfzx5Nd1jd'

variables is a 2-dimensional dictionary, and the value corresponding to each of its keys is also a dictionary.

The keys of the variables dictionary are 'Room Temp', 'LED On', 'CPU Temp', 'STATUS', 'Location', which are all data displayed on the Control Panel’s widgets.

The value of each key in the variables dictionary is also a dictionary, and the keys of these dictionaries are the same, where the value of the 'bind' key is a function that can return the transferred content, and the 'type' is the data type of the transferred content ('numeric' is a numeric type, 'string' is a string type, 'bool' is a boolean type, and 'location' is a list containing two dictionaries).

Through the analysis of the variables dictionary, we can know that Cloud4RPi will read the keys of the variables dictionary and display the value corresponding to the key in the Control Panel. Obviously we cannot change the keys of the variables dictionary, but we can change the value in the key (the value of the 'bind' dictionary) to let the widgets display the content we want.

For example, if we want to send humidity values to Cloud4RPi, we cannot add a new key to the variables dictionary, but we can borrow a key, such as the 'Room Temp' key, and then write the function that returns the humidity value in the corresponding 'bind' key.

variables = {
    'Room Temp': {
        'type': 'numeric' if ds_sensors else 'string',
        'bind': ds_sensors[0] if ds_sensors else sensor_not_connected
    'LED On': {
        'type': 'bool',
        'value': False,
        'bind': led_control
    'CPU Temp': {
        'type': 'numeric',
        'bind': rpi.cpu_temp
    'STATUS': {
        'type': 'string',
        'bind': listen_for_events
    'Location': {
        'type': 'location',
        'bind': get_location

The vdiagnostics stores information about the Raspberry Pi and is used to verify and prevent misconnections.

vdiagnostics = {
    'CPU Temp': rpi.cpu_temp,
    'IP Address': rpi.ip_address,
    'Host': rpi.host_name,
    'Operating System': rpi.os_name,
    'Client Version:': cloud4rpi.__version__,