samples: get and upload temperature to DRM in the tank demo

The temperature is obtained from the I2C sensor.

Signed-off-by: Ruben Moral <ruben.moral@digi.com>

Author: rubenmoral

samples/demos/end_to_end_tank/README.md

@@ -57,6 +57,11 @@ The example is already configured, so all you need to do is build and launch
 the project. Then, read the demo documentation for more information about how
 to test the demo.
 
+Required libraries
+--------------------
+
+* hdc1080
+
 Supported platforms
 -------------------
 

samples/demos/end_to_end_tank/main.py

@@ -24,9 +24,11 @@
 import xbee
 
 from digi import cloud
-from machine import Pin
+from machine import I2C, Pin
 from xbee import relay
 
+from hdc1080 import HDC1080
+
 # Constants.
 ITEM_OP = "operation"
 ITEM_STATUS = "status"
@@ -47,6 +49,7 @@
 
 DEFAULT_TANK_LEVEL = 50.0       # 50 %
 DEFAULT_VALVE_POSITION = False  # Closed
+DEFAULT_TEMPERATURE = 21.0      # 21 C
 DEFAULT_REPORT_INTERVAL = 60    # 1 minute
 
 TANK_DRAIN_RATE = 0.005  # 0.005 % / second
@@ -75,6 +78,7 @@
 
 DATAPOINT_LEVEL = "level"
 DATAPOINT_VALVE = "valve"
+DATAPOINT_TEMPERATURE = "temperature"
 
 DRM_REQ_ON = "VALVE_ON"
 DRM_REQ_OFF = "VALVE_OFF"
@@ -113,6 +117,8 @@
 led_pin = Pin(LED_PIN_ID, Pin.OUT, value=VALUE_DISABLED)
 btn_pin = Pin(BTN_PIN_ID, Pin.IN, Pin.PULL_UP)
 
+sensor = None
+
 
 def read_properties():
     """
@@ -403,6 +409,23 @@ def reset_water_flow_vars():
         valve_open_time = time.time()
 
 
+def get_tank_temperature():
+    """
+    Reads the tank temperature from the I2C sensor and returns it.
+
+    Returns:
+        The tank temperature.
+    """
+    if sensor is None:
+        return DEFAULT_TEMPERATURE
+
+    try:
+        # Read the temperature from the I2C sensor.
+        return sensor.read_temperature(True)
+    except OSError:
+        return DEFAULT_TEMPERATURE
+
+
 def process_drm_request(request):
     """
     Processes the given DRM request.
@@ -455,16 +478,19 @@ def upload_sensor_data():
     # Calculate the new tank level.
     calculate_tank_level()
     tank_level_f = "{:.2f}".format(tank_level)
+    tank_temperature_f = "{:.2f}".format(get_tank_temperature())
 
     # print debug traces.
     print("- Sending sensor values to DRM:")
     print("  - Tank level: {} %".format(tank_level_f))
     print("  - Tank valve: {}".format("Open" if tank_valve_open else "Closed"))
+    print("  - Tank temperature: {} C".format(tank_temperature_f))
 
     # Upload the samples to DRM.
     data = cloud.DataPoints()
-    data.add(DATAPOINT_LEVEL, tank_level_f)
+    data.add(DATAPOINT_LEVEL, tank_level_f, units="%")
     data.add(DATAPOINT_VALVE, int(tank_valve_open))
+    data.add(DATAPOINT_TEMPERATURE, tank_temperature_f, units="C")
     try:
         data.send(timeout=60)
     except OSError as e:
@@ -500,6 +526,7 @@ def main():
     Main execution of the application.
     """
     # Initialize variables.
+    global sensor
     global identified
     global finished
 
@@ -511,6 +538,12 @@ def main():
     print(" | End-to-End IoT Tank Monitoring Sample |")
     print(" +---------------------------------------+\n")
 
+    # Instantiate the HDC1080 peripheral.
+    try:
+        sensor = HDC1080(I2C(1))
+    except AssertionError:
+        pass
+
     # Configure the Bluetooth advertisement.
     config_advertisement()