public void Start(TimeSpan duration)
{
if (duration.TotalSeconds > 5.0 || duration.TotalSeconds < 0.0)
throw new ArgumentOutOfRangeException("duration", duration, "duration must be between 0 and 5 seconds");
var vibrator = (Vibrator)Application.Context.GetSystemService(Context.VibratorService);
vibrator.Vibrate((long)duration.TotalMilliseconds);
}