Split large measurements and simplify complex example.

Author: tannewt

adafruit_ble_broadcastnet.py

@@ -55,19 +55,21 @@
 
 _ble = adafruit_ble.BLERadio()
 _sequence_number = 0
-def broadcast(measurement, *, broadcast_time=0.1):
+def broadcast(measurement, *, broadcast_time=0.1, extended=False):
+    """Broadcasts the given measurement for the given broadcast time. If extended is False and the
+       measurement would be too long, it will be split into multiple measurements for transmission."""
     global _sequence_number
-    measurement.sequence_number = _sequence_number
-    _ble.start_advertising(measurement, scan_response=None)
-    time.sleep(broadcast_time)
-    _ble.stop_advertising()
-    _sequence_number = (_sequence_number + 1) % 256
+    for submeasurement in measurement.split(252 if extended else 31):
+        submeasurement.sequence_number = _sequence_number
+        _ble.start_advertising(submeasurement, scan_response=None)
+        time.sleep(broadcast_time)
+        _ble.stop_advertising()
+        _sequence_number = (_sequence_number + 1) % 256
 
 device_address = "{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}".format(*_ble._adapter.address.address_bytes)
 
 _MANUFACTURING_DATA_ADT = const(0xff)
 _ADAFRUIT_COMPANY_ID = const(0x0822)
-_SENSOR_DATA_ID = const(0x0002)
 
 class AdafruitSensorMeasurement(Advertisement):
     """Broadcast a single RGB color."""
@@ -167,3 +169,27 @@ def __str__(self):
                 if value is not None:
                     parts.append("{}={}".format(attr, str(value)))
         return "<{} {} >".format(self.__class__.__name__, " ".join(parts))
+
+    def split(self, max_packet_size=31):
+        current_size = 8 # baseline for mfg data and sequence number
+        if current_size + len(self.manufacturer_data) < max_packet_size:
+            yield self
+            return
+
+        original_data = self.manufacturer_data.data
+        submeasurement = None
+        for key in original_data:
+            value = original_data[key]
+            entry_size = 2 + len(value)
+            if not submeasurement or current_size + entry_size > max_packet_size:
+                if submeasurement:
+                    yield submeasurement
+                submeasurement = self.__class__()
+                current_size = 8
+            submeasurement.manufacturer_data.data[key] = value
+            current_size += entry_size
+
+        if submeasurement:
+            yield submeasurement
+
+        return

examples/ble_broadcastnet_multisensor.py

@@ -31,51 +31,13 @@
 # Barometric pressure sensor:
 bmp280 = adafruit_bmp280.Adafruit_BMP280_I2C(i2c)
 
-last_sht31d_temperature = None
-last_sht31d_relative_humidity = None
-last_bmp280_temperature = None
-last_bmp280_pressure = None
-last_lsm6ds_acceleration = None
-last_lis3mdl_magnetic = None
-
 while True:
     measurement = adafruit_ble_broadcastnet.AdafruitSensorMeasurement()
-
-    # Handle the two temperature measurements. We must always provide both because they split into
-    # feeds based on the position in the field.
-    sht31d_temperature = round(sht31d.temperature, 0)
-    bmp280_temperature = round(bmp280.temperature, 0)
-    if (sht31d_temperature != last_sht31d_temperature or
-        bmp280_temperature != last_bmp280_temperature):
-        measurement.temperature = (sht31d_temperature, bmp280_temperature)
-        last_sht31d_temperature = sht31d_temperature
-        last_bmp280_temperature = bmp280_temperature
-
-    # Relative humidity, rounded to the nearest whole integer.
-    sht31d_relative_humidity = round(sht31d.relative_humidity, 0)
-    if sht31d_relative_humidity != last_sht31d_relative_humidity:
-        measurement.relative_humidity = sht31d_relative_humidity
-        last_sht31d_relative_humidity = sht31d_relative_humidity
-
-    # Pressure, round to one decimal place.
-    bmp280_pressure = round(bmp280.pressure, 1)
-    if bmp280_pressure != last_bmp280_pressure:
-        measurement.pressure = bmp280_pressure
-        last_bmp280_pressure = bmp280_pressure
-
-    # Acceleration, each axis rounded to one decimal place.
-    lsm6ds_acceleration = tuple([round(axis, 1) for axis in lsm6ds.acceleration])
-    if lsm6ds_acceleration != last_lsm6ds_acceleration:
-        measurement.acceleration = lsm6ds_acceleration
-        last_lsm6ds_acceleration = lsm6ds_acceleration
-
-    # Magnetic, each axis rounded to two decimal places.
-    lis3mdl_magnetic = tuple([round(axis, 2) for axis in lis3mdl.magnetic])
-    if lis3mdl_magnetic != last_lis3mdl_magnetic:
-        measurement.magnetic = lis3mdl_magnetic
-        last_lis3mdl_magnetic = lis3mdl_magnetic
-
-    if measurement:
-        print(measurement)
-        adafruit_ble_broadcastnet.broadcast(measurement)
-    time.sleep(10)
+    measurement.temperature = (sht31d.temperature, bmp280.temperature)
+    measurement.relative_humidity = sht31d.relative_humidity
+    measurement.pressure = bmp280.pressure
+    measurement.acceleration = lsm6ds.acceleration
+    measurement.magnetic = lis3mdl.magnetic
+    print(measurement)
+    adafruit_ble_broadcastnet.broadcast(measurement)
+    time.sleep(60)