if(amplitude > 255 || amplitude < 1)

amplitude = VibrationEffect.DEFAULT_AMPLITUDE;

app/src/main/java/de/edotzlaff/schockwelle/SensorMapsActivity.java

@@ -146,8 +146,11 @@ public class SensorMapsActivity extends FragmentActivity implements OnMapReadyCa
         if(!mDeviceCanVibrate)
             return;
 
+
         Vibrator v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
-        if (Build.VERSION.SDK_INT >= 26) {
+        if(amplitude > 255 || amplitude < 1)
+            amplitude = VibrationEffect.DEFAULT_AMPLITUDE;
+      if (Build.VERSION.SDK_INT >= 26) {
             if(duration == 0)
             {
                 v.cancel(); //stop vibration if still running