public async Task <double> GetDistanceInCmAsync(int timeoutInMilliseconds)
{
double distance = MAX_DISTANCE_cm;
_ticks = 0L;
long ticktimeout = timeoutInMilliseconds * _ticks_per_second / 1000;
bool find_edge = Edge.leading;
try
{
_stopwatch.Reset();
await SendPulse(PULSE_WIDTH_ms);
_stopwatch.Start();
while (_ticks < ticktimeout)
{
if (find_edge == _hat.ReadDigital(FEZHAT.DigitalPin.DIO16))
{
if (find_edge)
{
find_edge = Edge.trailing;
}
else
{
break;
}
}
await Task.Delay(TimeSpan.FromTicks(_tick_resolution));
_ticks = _stopwatch.ElapsedTicks;
}
}
finally
{
_stopwatch.Stop();
distance = _ticks * SPEED_OF_SOUND_cmps / _ticks_per_second / 2.0;
}
return(Math.Round(distance * 10.0) / 10.0); // round to 1 decimal place
}