Add battery voltage and more examples.

Author: tannewt

adafruit_ble_broadcastnet.py

@@ -149,6 +149,10 @@ class AdafruitSensorMeasurement(Advertisement):
     weight = ManufacturerDataField(0x0a14, "<f")
     """Weight as a float in grams."""
 
+    battery_voltage = ManufacturerDataField(0x0a15, "<H")
+    """Battery voltage in millivolts. Saves two bytes over voltage and is more readable in bare
+       packets."""
+
     def __init__(self, *, sequence_number=None):
         super().__init__()
         if sequence_number:

examples/ble_broadcastnet_battery_level.py

@@ -0,0 +1,21 @@
+import adafruit_ble_broadcastnet
+import analogio
+import board
+import math
+import microcontroller
+import time
+
+print("This is BroadcastNet sensor:", adafruit_ble_broadcastnet.device_address)
+
+battery = analogio.AnalogIn(board.VOLTAGE_MONITOR)
+divider_ratio = 2
+
+while True:
+    measurement = adafruit_ble_broadcastnet.AdafruitSensorMeasurement()
+    battery_voltage = battery.value / 2**16 * divider_ratio * battery.reference_voltage
+    measurement.battery_voltage = int(battery_voltage * 1000)
+    measurement.temperature = microcontroller.cpu.temperature
+    print(measurement)
+    adafruit_ble_broadcastnet.broadcast(measurement)
+
+    time.sleep(30)

examples/ble_broadcastnet_expo_backoff.py

@@ -0,0 +1,39 @@
+"""This example uses the internal temperature sensor and reports the battery voltage. However, it
+   reads the temperature more often but only reports it when it's changed by a degree since the last
+   report. When doing a report it will actually do multiple broadcasts and wait 2 ** n readings
+   until the next broadcast. The delay is reset every time the temp moves more than 1 degree."""
+
+import adafruit_ble_broadcastnet
+import analogio
+import board
+import math
+import microcontroller
+import time
+
+print("This is BroadcastNet sensor:", adafruit_ble_broadcastnet.device_address)
+
+battery = analogio.AnalogIn(board.VOLTAGE_MONITOR)
+divider_ratio = 2
+
+last_temperature = None
+consecutive = 1
+while True:
+    temp = microcontroller.cpu.temperature
+    if not last_temperature or abs(temp - last_temperature) > 1:
+        consecutive = 1
+        last_temperature = temp
+    else:
+        consecutive += 1
+
+    # Repeatedly broadcast identical values to help ensure it is picked up by the bridge. Perform
+    # exponential backoff as we get more confidence.
+    exp = int(math.log(consecutive, 2))
+    if 2 ** exp == consecutive:
+        measurement = adafruit_ble_broadcastnet.AdafruitSensorMeasurement()
+        battery_voltage = battery.value / 2**16 * divider_ratio * battery.reference_voltage
+        measurement.battery_voltage = int(battery_voltage * 1000)
+        measurement.temperature = temp
+        print(measurement)
+        adafruit_ble_broadcastnet.broadcast(measurement)
+
+    time.sleep(1)

examples/ble_broadcastnet_simpletest.py

@@ -1,21 +1,15 @@
-"""This is a basic sensor node that uses the internal temperature sensor."""
+"""This is a basic sensor node that uses the internal temperature sensor and reports it every 10
+   seconds."""
 
 import adafruit_ble_broadcastnet
 import microcontroller
 import time
 
 print("This is BroadcastNet sensor:", adafruit_ble_broadcastnet.device_address)
 
-last_temperature = None
 while True:
-    temp = microcontroller.cpu.temperature
-    # Round the temperature to the nearest degree to reduce how often it is
-    # broadcast.
-    temp = round(temp, 0)
-    if temp != last_temperature:
-        measurement = adafruit_ble_broadcastnet.AdafruitSensorMeasurement()
-        measurement.temperature = temp
-        print(measurement)
-        adafruit_ble_broadcastnet.broadcast(measurement)
-    last_temperature = temp
+    measurement = adafruit_ble_broadcastnet.AdafruitSensorMeasurement()
+    measurement.temperature = microcontroller.cpu.temperature
+    print(measurement)
+    adafruit_ble_broadcastnet.broadcast(measurement)
     time.sleep(10)