mirror of
https://github.com/arduino/Arduino.git
synced 2024-12-04 15:24:12 +01:00
74 lines
2.2 KiB
Plaintext
74 lines
2.2 KiB
Plaintext
/*
|
|
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 7 to +5V
|
|
* 10K resistor attached from pin 7 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 17 Jun 2009
|
|
by Tom Igoe
|
|
|
|
|
|
http://www.arduino.cc/en/Tutorial/Debounce
|
|
*/
|
|
|
|
// constants won't change. They're used here to
|
|
// set pin numbers:
|
|
const int buttonPin = 7; // 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 follow 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 = 200; // the debounce time, increase if the output flickers
|
|
|
|
void setup() {
|
|
pinMode(buttonPin, INPUT);
|
|
pinMode(ledPin, OUTPUT);
|
|
}
|
|
|
|
void loop() {
|
|
buttonState = 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 ((buttonState == HIGH) &&
|
|
(lastButtonState == LOW) &&
|
|
(millis() - lastDebounceTime) > debounceDelay) {
|
|
// toggle the output
|
|
if (ledState == HIGH) {
|
|
ledState = LOW;
|
|
} else {
|
|
ledState = HIGH;
|
|
}
|
|
// ... and store the time of the last button press
|
|
// in a variable:
|
|
lastDebounceTime = millis();
|
|
}
|
|
|
|
// set the LED using the ledState variable:
|
|
digitalWrite(ledPin, ledState);
|
|
|
|
// save the buttonState. Next time through the loop,
|
|
// it'll be the lastButtonState:
|
|
lastButtonState = buttonState;
|
|
}
|