/// <summary>
/// Called when a single infrared sensor pulse becomes available.
/// </summary>
/// <param name="pulse">The pulse.</param>
private void OnInfraredSensorPulseAvailable(InfraredPulse pulse)
{
if (_isDisposed || PulseAvailable == null)
{
return;
}
var args = new InfraredSensorPulseEventArgs(pulse);
ThreadPool.QueueUserWorkItem(a =>
{
PulseAvailable?.Invoke(this, a as InfraredSensorPulseEventArgs);
},
args);
}
/// <summary>
/// Initializes a new instance of the <see cref="InfraredSensorPulseEventArgs" /> class.
/// </summary>
/// <param name="pulse">The pulse.</param>
internal InfraredSensorPulseEventArgs(InfraredPulse pulse)
{
Value = pulse.Value;
DurationUsecs = pulse.DurationUsecs;
}
/// <summary>
/// Reads the interrupt do work.
/// </summary>
private void ReadInterruptDoWork()
{
// Define some constants
const long gapUsecs = 5000;
const long maxElapsedMicroseconds = 250000;
const long minElapsedMicroseconds = 50;
const int idleCheckIntervalMilliSecs = 32;
const int maxPulseCount = 128;
// Setup the input pin
InputPin.PinMode = GpioPinDriveMode.Input;
InputPin.InputPullMode = GpioPinResistorPullMode.PullUp;
// Get the timers started!
var pulseTimer = new HighResolutionTimer();
var idleTimer = new HighResolutionTimer();
var pulseBuffer = new List <InfraredPulse>(maxPulseCount);
var syncLock = new object();
_idleChecker = new Timer(s =>
{
if (_isDisposed || _isInReadInterrupt)
{
return;
}
lock (syncLock)
{
if (idleTimer.ElapsedMicroseconds < gapUsecs || idleTimer.IsRunning == false || pulseBuffer.Count <= 0)
{
return;
}
OnInfraredSensorRawDataAvailable(pulseBuffer.ToArray(), ReceiverFlushReason.Idle);
pulseBuffer.Clear();
idleTimer.Reset();
}
});
InputPin.RegisterInterruptCallback(EdgeDetection.FallingAndRisingEdge, () =>
{
if (_isDisposed)
{
return;
}
_isInReadInterrupt = true;
lock (syncLock)
{
idleTimer.Restart();
_idleChecker.Change(idleCheckIntervalMilliSecs, idleCheckIntervalMilliSecs);
var currentLength = pulseTimer.ElapsedMicroseconds;
var pulse = new InfraredPulse(
IsActiveLow ? !_currentValue : _currentValue,
currentLength.Clamp(minElapsedMicroseconds, maxElapsedMicroseconds));
// Restart for the next bit coming in
pulseTimer.Restart();
// For the next value
_currentValue = InputPin.Read();
// Do not add an idling pulse
if (pulse.DurationUsecs < maxElapsedMicroseconds)
{
pulseBuffer.Add(pulse);
OnInfraredSensorPulseAvailable(pulse);
}
if (pulseBuffer.Count >= maxPulseCount)
{
OnInfraredSensorRawDataAvailable(pulseBuffer.ToArray(), ReceiverFlushReason.Overflow);
pulseBuffer.Clear();
}
}
_isInReadInterrupt = false;
});
// Get the timers started
pulseTimer.Start();
idleTimer.Start();
_idleChecker.Change(0, idleCheckIntervalMilliSecs);
}
