counting how many times a button has been pressed

Hello everybody,

For checking a the number of times a button (connected to pin 12) has been pressed I wrote this small program. The program " buttoncount.ino" is also included as attachment.

int buttonPushCounter = 0;
int buttonState = 1;
int lastButtonState = 1;

void setup(){
Serial.begin(9600);
digitalWrite(11,HIGH);//activation of the pull-up resistor of pin 11
}

void loop(){
buttonState = digitalRead(11);
if (buttonState != lastButtonState) {
if (buttonState == LOW) {
buttonPushCounter++;
}
}
lastButtonState = buttonState;
Serial.println(buttonPushCounter);
}

It seems to work but when I integrate it in a bigger program (used as a library) the counting doesn’t detect all the presses. And often it jumps in steps of two (especially when I tap the button and don’t hold it for 0.5s).

Anyone an idea what is wrong?

Thanks in advance,
Bart

buttoncount.ino (434 Bytes)

const int buttonPin = 12;    // 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;
}

check the code. it will work for you. i have not added counter variable. please include it

This:

digitalWrite(11,HIGH);//activation of the pull-up resistor of pin 11

Should be:

pinMode (11, INPUT_PULLUP); // pin 11 is set as input using internal pull-up

Try including a button debounce code here and here.

**Or use the code AMPS-N posted.