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KY-004: Skillnad mellan sidversioner
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<pre> | <pre> | ||
/* | |||
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 | |||
modified 28 Dec 2012 | |||
by Mike Walters | |||
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); | |||
// set initial LED state | |||
digitalWrite(ledPin, ledState); | |||
} | |||
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: | |||
// if the button state has changed: | |||
if (reading != buttonState) { | |||
buttonState = reading; | |||
// only toggle the LED if the new button state is HIGH | |||
if (buttonState == HIGH) { | |||
ledState = !ledState; | |||
} | |||
} | |||
} | |||
// set the LED: | |||
digitalWrite(ledPin, ledState); | |||
// save the reading. Next time through the loop, | |||
// it'll be the lastButtonState: | |||
lastButtonState = reading; | |||
} | |||
</pre> | </pre> | ||