public DhtData GetData()
{
// pull pin down for 18ms
pin.Write(false);
Timer.Sleep(18m);
// pull pin up for 40µs
pin.Write(true);
Timer.Sleep(40m / 1000m);
pin.Wait(true, 40m / 1000m);
// Wait for pin to be down (at most 80µs)
pin.Wait(false, 80m / 1000m);
// Wait for pin to be up (at most 80µs)
pin.Wait(true, 80m / 1000m);
var data = new byte[] { 0, 0, 0, 0, 0 };
for (var i = 0; i < 5; i++)
{
for (var j = 0; j < 8; j++)
{
pin.Wait(false, 50m / 1000m);
var start = DateTime.UtcNow;
pin.Wait(true, 100m / 1000m);
// bit "0" has 26-28us high-voltage length, bit "1" has 70us high-voltage length
var value = (DateTime.UtcNow - start).TotalMilliseconds > 40.0 / 1000 ? 1 : 0;
data[i] = (byte)(data[i] << 1 + value);
}
}
Console.WriteLine(
"{0:X2} {1:X2} {2:X2} {3:X2} {4:X2}",
data[0],
data[1],
data[2],
data[3],
data[4]);
var checkSum = data[0] + data[1] + data[2] + data[3];
if ((checkSum & 0xff) != data[4])
{
throw new InvalidOperationException("Checksum is not valid");
}
pin.Write(true);
return(new DhtData
{
Humidity = (data[0] << 8 + data[1]) / 10.0m,
Temperature = ((data[2] & 0x80) == 0 ? 1 : -1) * ((data[2] & 0x7F) << 8 + data[3]) / 10.0m
});
}
public DhtConnection(IInputOutputBinaryPin pin)
{
this.pin = pin;
pin.Write(true);
Timer.Sleep(100);
}
public DhtConnection(IInputOutputBinaryPin pin)
{
this.pin = pin;
pin.Write(true);
Timer.Sleep(100);
}
public void Write(bool state)
{
lock (_syncRoot)
{
_lastWriteState = state;
_connection.Write(state);
//Logger.Log(_pin + " > " + state);
}
}
private void SendData(uint data)
{
// Send 16 bit data
for (int i = 0; i < 16; i++)
{
bool state = ((data & 0x8000) > 0);
dataPin.Write(state);
state = !clockPin.Read();
clockPin.Write(state);
data <<= 1;
}
}
/// <summary>
/// Starts the DHT sensor. If not called, sensor will be automatically enabled before getting data.
/// </summary>
public void Start()
{
started = true;
pin.Write(true);
previousRead = DateTime.UtcNow;
}