Changes between Initial Version and Version 1 of ControlSystems/SoftwareTeam/Training/GettingStarted/Debouncing

Timestamp:

Feb 14, 2020, 1:05:45 AM (5 years ago)

Author:

David Albert

Comment:

--

ControlSystems/SoftwareTeam/Training/GettingStarted/Debouncing

@@ +1 @@
+There are many cases where a mechanical switch such as a button or a limit switch literally bounces when you change its position.  The process of ignoring the bouncing so you don't repeatedly act on the switch unintentionally is called de-bouncing.  There are several ways to do this; one is to start a timer when the switch change is detected and then ignore any subsequent switch changes until the timer expires.  The code looks like this:
+
+{{{
+import edu.wpi.first.wpilibj.XboxController;
+import edu.wpi.first.wpilibj.Timer;
+
+...
+public void robotInit() {
+   xbox = new XboxController(0);
+   debounce = new Timer();
+   debounce.start();
+}
+
+public void robot.periodic() {
+   if (xbox.getAButton()) {
+       // A button pressed
+       if (debounce.hasPeriodPassed(0.5)) {
+           // more than half-second since last press
+           System.out.println("A button pressed!");
+           // restart debounce timer so we ignore presses in next half second
+           debounce.reset();
+       }
+   }
+}
+}}}