可以参考这个代码:
- /*
- Debounce
-
- Each time the input pin goes from LOW to HIGH (e.g. because of a push-button
- press), the output pin is toggled from LOW to HIGH or HIGH to LOW. There's
- a minimum delay between toggles to debounce the circuit (i.e. to ignore
- noise).
-
- The circuit:
- * LED attached from pin 13 to ground
- * pushbutton attached from pin 2 to +5V
- * 10K resistor attached from pin 2 to ground
-
- * Note: On most Arduino boards, there is already an LED on the board
- connected to pin 13, so you don't need any extra components for this example.
-
-
- created 21 November 2006
- by David A. Mellis
- modified 30 Aug 2011
- by Limor Fried
-
- This example code is in the public domain.
-
- http://www.arduino.cc/en/Tutorial/Debounce
- */
-
- // constants won't change. They're used here to
- // set pin numbers:
- const int buttonPin = 2; // the number of the pushbutton pin
- const int ledPin = 13; // the number of the LED pin
-
- // Variables will change:
- int ledState = HIGH; // the current state of the output pin
- int buttonState; // the current reading from the input pin
- int lastButtonState = LOW; // the previous reading from the input pin
-
- // the following variables are long's because the time, measured in miliseconds,
- // will quickly become a bigger number than can be stored in an int.
- long lastDebounceTime = 0; // the last time the output pin was toggled
- long debounceDelay = 50; // the debounce time; increase if the output flickers
-
- void setup() {
- pinMode(buttonPin, INPUT);
- pinMode(ledPin, OUTPUT);
- }
-
- void loop() {
- // read the state of the switch into a local variable:
- int reading = digitalRead(buttonPin);
-
- // check to see if you just pressed the button
- // (i.e. the input went from LOW to HIGH), and you've waited
- // long enough since the last press to ignore any noise:
-
- // If the switch changed, due to noise or pressing:
- if (reading != lastButtonState) {
- // reset the debouncing timer
- lastDebounceTime = millis();
- }
-
- if ((millis() - lastDebounceTime) > debounceDelay) {
- // whatever the reading is at, it's been there for longer
- // than the debounce delay, so take it as the actual current state:
- buttonState = reading;
- }
-
- // set the LED using the state of the button:
- digitalWrite(ledPin, buttonState);
-
- // save the reading. Next time through the loop,
- // it'll be the lastButtonState:
- lastButtonState = reading;
- }
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