private async void Timer_Tick(object sender, object e)
{
try
{
// ***
// *** Stop the timer so we do not have more than reading
// *** at a time.
// ***
_timer.Stop();
// ***
// *** Increment the counter.
// ***
_totalRequests++;
// ***
// *** Read the sensor.
// ***
IDhtReading reading = await _sensor.GetReadingAsync();
// ***
// *** Check the result.
// ***
if (reading.Result == DhtReadingResult.Valid)
{
//float t = reading.Temperature * 1.8F + 32F; //fahrenheit
float t = reading.Temperature;//celsius
this.Temperature = t;
this.Humidity = reading.Humidity;
_successfulRequests++;
}
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(ex.Message);
}
finally
{
// ***
// *** Start the timer again.
// ***
_timer.Start();
}
// ***
// *** Update the success rate and running time.
// ***
this.RaisePropertyChanged(nameof(this.SuccessRate));
this.RaisePropertyChanged(nameof(this.RunningTime));
}
public async System.Threading.Tasks.Task getTempetureAsync()
{
IDhtReading reading = await _sensor.GetReadingAsync();
// ***
// *** Check the result.
// ***
if (reading.Result == DhtReadingResult.Valid)
{
System.Diagnostics.Debug.WriteLine($"Temperature = {reading.Temperature:0.0} C, Humidity = {reading.Humidity:0.0}%");
}
else
{
System.Diagnostics.Debug.WriteLine($"Error = {reading.Result}");
}
}
/// <summary>
/// Gets a reading from the sensor.
/// </summary>
/// <returns>Returns an IDhtReading instance containing
/// the data from the sensor.</returns>
public async Task <IDhtReading> GetReadingAsync()
{
IDhtReading reading = null;
for (var attempt = 0; attempt <= RetryCount; attempt++)
{
pin.Write(GpioPinValue.High);
pin.SetDriveMode(GpioPinDriveMode.Output);
if (last_success_timestamp == 0)
{
await Task.Delay(InitializationDelay);
}
else if (GetTickCount64() - last_success_timestamp < MinSampleInterval)
{
var delay = Math.Max(MinSampleInterval - (int)(GetTickCount64() - last_success_timestamp), ReinitializationDelay);
await Task.Delay(delay);
}
else
{
await Task.Delay(ReinitializationDelay);
}
reading = GetReading();
if (reading.Result == DhtReadingResult.Valid)
{
last_success_timestamp = GetTickCount64();
break;
}
last_success_timestamp = 0;
#if DEBUG
Debug.WriteLine($"Sensor read failed: {reading.Result}, attempt {attempt}");
#endif
}
return(reading);
}
