Workaround: Wahoo Tickr X repords cadence in SPM instead of RPM.

Fixes #1164.

src/main/java/de/dennisguse/opentracks/sensors/BluetoothConnectionManager.java

@@ -107,7 +107,6 @@ public abstract class BluetoothConnectionManager<DataType> {
         @Override
         public void onCharacteristicChanged(BluetoothGatt gatt, @NonNull BluetoothGattCharacteristic characteristic) {
             Log.d(TAG, "Received data from " + gatt.getDevice().getAddress());
-
             SensorData<DataType> sensorData = parsePayload(gatt.getDevice().getName(), gatt.getDevice().getAddress(), characteristic);
             if (sensorData != null) {
                 Log.d(TAG, "Decoded data from " + gatt.getDevice().getAddress() + ": " + sensorData);

src/main/java/de/dennisguse/opentracks/sensors/BluetoothUtils.java

@@ -165,6 +165,11 @@ public class BluetoothUtils {
         index = 3;
         if (valueLength - index >= 1) {
             cadence = Cadence.of(characteristic.getIntValue(BluetoothGattCharacteristic.FORMAT_UINT8, index));
+
+            // Hacky workaround as the Wahoo Tickr X provides cadence in SPM (steps per minute) in violation to the standard.
+            if (sensorName != null && sensorName.startsWith("TICKR X")) {
+                cadence = Cadence.of(cadence.getRPM() / 2);
+            }
         }
 
         index = 4;