app.py

import smbus2, bme280, os, asyncio, json
from dotenv import load_dotenv
from grove.grove_moisture_sensor import GroveMoistureSensor
from grove.grove_led import GroveLed
from azure.iot.device.aio import IoTHubDeviceClient, ProvisioningDeviceClient
from azure.iot.device import MethodResponse

# Configuration parameters
bme_pin = 1
bme_address = 0x76
moisture_pin = 2
led_pin = 16

# Create the sensors
bus = smbus2.SMBus(bme_pin)
calibration_params = bme280.load_calibration_params(bus, bme_address)

moisture_sensor = GroveMoistureSensor(moisture_pin)

# Create the LED
led = GroveLed(led_pin)

# Load the IoT Central connection parameters
load_dotenv()
id_scope = os.getenv('ID_SCOPE')
device_id = os.getenv('DEVICE_ID')
primary_key = os.getenv('PRIMARY_KEY')

def getTemperaturePressureHumidity():
    return bme280.sample(bus, bme_address, calibration_params)

def getMoisture():
    return moisture_sensor.moisture

def getTelemetryData():
    temp_pressure_humidity = getTemperaturePressureHumidity()
    moisture = getMoisture()

    data = {
        "humidity": round(temp_pressure_humidity.humidity, 2),
        "pressure": round(temp_pressure_humidity.pressure/10, 2),
        "temperature": round(temp_pressure_humidity.temperature, 2),
        "soil_moisture": round(moisture, 2)
    }

    return json.dumps(data)

async def main():
    # provision the device
    async def register_device():
        provisioning_device_client = ProvisioningDeviceClient.create_from_symmetric_key(
            provisioning_host='global.azure-devices-provisioning.net',
            registration_id=device_id,
            id_scope=id_scope,
            symmetric_key=primary_key)

        return await provisioning_device_client.register()

    results = await asyncio.gather(register_device())
    registration_result = results[0]

    # build the connection string
    conn_str='HostName=' + registration_result.registration_state.assigned_hub + \
                ';DeviceId=' + device_id + \
                ';SharedAccessKey=' + primary_key

    # The client object is used to interact with Azure IoT Central.
    device_client = IoTHubDeviceClient.create_from_connection_string(conn_str)

    # connect the client.
    print('Connecting')
    await device_client.connect()
    print('Connected')

    # listen for commands
    async def command_listener(device_client):
        while True:
            method_request = await device_client.receive_method_request('needs_watering')
            needs_watering = method_request.payload
            print('Needs watering:', needs_watering)
            payload = {'result': True}

            if needs_watering:
                led.on()
            else:
                led.off()

            method_response = MethodResponse.create_from_method_request(
                method_request, 200, payload
            )
            await device_client.send_method_response(method_response)

    # async loop that sends the telemetry
    async def main_loop():
        while True:            
            telemetry = getTelemetryData()
            print(telemetry)

            await device_client.send_message(telemetry)
            await asyncio.sleep(60)

    listeners = asyncio.gather(command_listener(device_client))

    await main_loop()

    # Cancel listening
    listeners.cancel()

    # Finally, disconnect
    await device_client.disconnect()

if __name__ == '__main__':
    asyncio.run(main())