private async Task SendPulse(double milliseconds)
{
_hat.WriteDigital(FEZHAT.DigitalPin.DIO26, true); // trigger
await Task.Delay(TimeSpan.FromMilliseconds(milliseconds));
_hat.WriteDigital(FEZHAT.DigitalPin.DIO26, false); // trigger
}
//private bool _complete;
public UltrasonicDistanceSensor(FEZHAT hat)
{
_stopwatch = new Stopwatch();
_ticks_per_second = Stopwatch.Frequency;
_tick_resolution = (long)(RESOLUTION_cm * _ticks_per_second / SPEED_OF_SOUND_cmps * 2.0);
_hat = hat;
_hat.WriteDigital(FEZHAT.DigitalPin.DIO26, false); // clear trigger
}