Hi, is there a way to count the number of times a button is pushed and then displaying that value to serial monitor?
Yes there is. Lots of examples if you google for it.
Please take a look at the "state change detection" example that came with your Arduino environment. You can get there by clicking File / Examples / 02.Digital / state change detection. I have copied it here for your convenience.
/*
State change detection (edge detection)
Often, you don't need to know the state of a digital input all the time,
but you just need to know when the input changes from one state to another.
For example, you want to know when a button goes from OFF to ON. This is called
state change detection, or edge detection.
This example shows how to detect when a button or button changes from off to on
and on to off.
The circuit:
* pushbutton attached to pin 2 from +5V
* 10K resistor attached to pin 2 from ground
* LED attached from pin 13 to ground (or use the built-in LED on
most Arduino boards)
created 27 Sep 2005
modified 30 Aug 2011
by Tom Igoe
This example code is in the public domain.
http://arduino.cc/en/Tutorial/ButtonStateChange
*/
// this constant won't change:
const int buttonPin = 2; // the pin that the pushbutton is attached to
const int ledPin = 13; // the pin that the LED is attached to
// Variables will change:
int buttonPushCounter = 0; // counter for the number of button presses
int buttonState = 0; // current state of the button
int lastButtonState = 0; // previous state of the button
void setup() {
// initialize the button pin as a input:
pinMode(buttonPin, INPUT);
// initialize the LED as an output:
pinMode(ledPin, OUTPUT);
// initialize serial communication:
Serial.begin(9600);
}
void loop() {
// read the pushbutton input pin:
buttonState = digitalRead(buttonPin);
// compare the buttonState to its previous state
if (buttonState != lastButtonState) {
// if the state has changed, increment the counter
if (buttonState == HIGH) {
// if the current state is HIGH then the button
// wend from off to on:
buttonPushCounter++;
Serial.println("on");
Serial.print("number of button pushes: ");
Serial.println(buttonPushCounter);
}
else {
// if the current state is LOW then the button
// wend from on to off:
Serial.println("off");
}
}
// save the current state as the last state,
//for next time through the loop
lastButtonState = buttonState;
// turns on the LED every four button pushes by
// checking the modulo of the button push counter.
// the modulo function gives you the remainder of
// the division of two numbers:
if (buttonPushCounter % 4 == 0) {
digitalWrite(ledPin, HIGH);
} else {
digitalWrite(ledPin, LOW);
}
}
Unfortunately, you will find that code very unreliable.
Most of the time it will work, but often it will give erratic and random results.
The problem is called "contact bounce" - do some Googling on that and then study the "Debounce" tutorials on the Arduino system.
Unfortunately, there is one further annoyance - or at least I find it so. All these examples seem to tell you to connect the button to 5V and use a pull-down resistor. In real practice, you want to connect the button to ground and use the internal pull-up of the Atmel chip. You write the logic accordingly, regarding LOW as active. This not only saves a resistor - perhaps somewhat trivial - but is much safer design practice since you are not potentially connecting external components such as buttons which may be on the end of a cable - to your supply line.
1 Like
to avoid contact bounce you can use a specific library
http://playground.arduino.cc/code/bounce
or, if you don't need very fast inputs you can simply add a delay(10); where the new input is taken
this is my code
button = digitalRead( buttonpin );
if (button==1&&lastbuttonstate==0)
{
++event;
lastbuttonstate=1;
delay(10);
}
else
{
if (button==0&&lastbuttonstate==1)
{
lastbuttonstate=0;
delay(10);
}