/// <summary> /// Constructor /// </summary> /// <param name="stateMachineInputCallback">delegate to call when there's an event to report</param> public DelcomLight(MainAppLogic.EnqueueStateMachineInput stateMachineInputCallback, TimeSpan holdTime) { hUSB = DelcomLightWrapper.TryOpeningDelcomDevice(); Delcom.DelcomEnableAutoConfirm(hUSB, 0); // Make sure we always start turned off DelcomLightWrapper.DelcomLEDAllAction(hUSB, DelcomLightWrapper.LightStates.Off); // remember the delegate so we can invoke when we get input this.stateMachineInputCallback = stateMachineInputCallback; //Initialize hold threshold from argument passed from Main this.holdThreshold = holdTime; // start a background thread to poll the device for input BackgroundWorker bgw1 = new BackgroundWorker(); bgw1.DoWork += delegate { this.BackgroundPollingWorker(); }; bgw1.RunWorkerAsync(); }
/// <summary> /// Runs on a background thread to monitor the button state and will dispatch events back to the main thread /// </summary> private void BackgroundPollingWorker() { ButtonState currentState = ButtonState.NotPressed; int iterationsSinceLastButtonRelease = 0; int iterationsSinceLastButtonDown = 0; const int buttonReleaseTolerance = 2; // magic number that works well in practice //Timer to determine how long the button has been held down for TimeSpan holdDuration = TimeSpan.Zero; //The time when the button was last in a down state. Used for hardware error correction. DateTime lastButtonDownTime = DateTime.MinValue; //The time when the button was last in an up state. Used for hardware error correction. DateTime lastButtonUpTime = DateTime.MinValue; //Boolean switch for determining if a button was held for longer than the hold threshold while it is still being held down. Boolean buttonHeld = false; // Loop endlessly until we're asked to stop while (!this.shouldStop) { //Check if light is still connected bool isStillConnected = DelcomLightWrapper.isButtonConnected(hUSB); //If not still connected, start loop to poll for connection until it is connected. if (!isStillConnected) { DelcomLightWrapper.CloseDelcomDevice(hUSB); hUSB = DelcomLightWrapper.TryOpeningDelcomDevice(); } if ((DateTime.UtcNow - lastButtonUpTime) > minTimeBetweenClicks) { // Get the current state of the button ButtonState newState = DelcomLightWrapper.DelcomGetButtonStatus(hUSB); if (newState == ButtonState.Unknown) { throw new NotImplementedException(); } else if (newState != currentState) { // The state has changed, so we need to handle it if (newState == ButtonState.NotPressed) { // We were previously in a pressed state, but the button on the light is flaky, so we need // to make sure the button has really been released, so we'll wait a few iterations. iterationsSinceLastButtonRelease++; if (iterationsSinceLastButtonRelease > buttonReleaseTolerance) { // Only remember the currentstate as changed if we're outside of our tolerance currentState = newState; //Button just released so reset timer iterationsSinceLastButtonRelease = 0; //Fire a button up event. This will only cause the state machine to act if in a previewing state with nothing queued. //It will turn off the red light that is on when the button is being held down in that case if (stateMachineInputCallback != null) { StateMachine.StateMachineInputArgs buttonUpArgs = new StateMachine.StateMachineInputArgs(StateMachine.StateMachineInput.ButtonUp); stateMachineInputCallback(buttonUpArgs); } //If a button held event was already fired, we don't want to fire a button pressed event in this case if (!buttonHeld) { // Notify that we've had a button press if (stateMachineInputCallback != null) { StateMachine.StateMachineInputArgs buttonArgs = new StateMachine.StateMachineInputArgs(StateMachine.StateMachineInput.ButtonPressed); stateMachineInputCallback(buttonArgs); } } lastButtonUpTime = DateTime.UtcNow; //reset button held, as it is no longer being held if it was before buttonHeld = false; } } else if (newState == ButtonState.Pressed) { // We were previously in a pressed state, but the button on the light is flaky, so we need // to make sure the button has really been released, so we'll wait a few iterations. iterationsSinceLastButtonDown++; if (iterationsSinceLastButtonDown > buttonReleaseTolerance) { // The button has just been pressed // Only remember the current state as changed if we're outside of our tolerance currentState = newState; //Button just pressed so reset timer iterationsSinceLastButtonRelease = 0; //Fire a button down event. This will only cause the state machine to act if in a previewing state with nothing queued. //It will turn on the red light that is on when the button is being held down in that case if (stateMachineInputCallback != null) { StateMachine.StateMachineInputArgs buttonArgs = new StateMachine.StateMachineInputArgs(StateMachine.StateMachineInput.ButtonDown); stateMachineInputCallback(buttonArgs); } //Set last button down time to current time, as button was just pressed down lastButtonDownTime = DateTime.UtcNow; } } } else if (newState == ButtonState.Pressed) { //Button has been held, check if hold is greater than threshold holdDuration = DateTime.UtcNow - lastButtonDownTime; //Reset iterations since last release iterationsSinceLastButtonRelease = 0; //If button held event has already been fired, we don't want to fire again until the button has been released if (!buttonHeld) { //If hold duration is greater than threshold we should fire a button held event if (holdDuration > holdThreshold) { // Notify that we've had a button held if (stateMachineInputCallback != null) { StateMachine.StateMachineInputArgs buttonArgs = new StateMachine.StateMachineInputArgs(StateMachine.StateMachineInput.ButtonHeld, holdDuration); stateMachineInputCallback(buttonArgs); } //We fired a button held event, so set this to true to prevent the event from being fired again while the button is still being held down. buttonHeld = true; } } } else if (newState == ButtonState.NotPressed) { //Reset iterations since last press iterationsSinceLastButtonDown = 0; } } System.Threading.Thread.Sleep(RRLightProgram.Properties.Settings.Default.LightPollingIntervalMS); } }