makitprojects - Arduino pushButton to switch

Arduino pushButton to switch

Today we’re going to show how to use a pushButton as a switch just by programming Arduino.

PushButtons can activate an output (eg buzzer or a led) when we press them. This works for a buzzer or a ring-bell, but, what if we want to use the pushButton as a switch [1]?

In order to do this, we are going to use a variable which we will toggle (from 0 to 1 and viceversa) each time we press the push button. Then we are going to use the state of that variable to turn the led on or off with an if statement.

[1]: Remember that a switch button changes its state when we press it and remains in that state until we press it again. On the other hand, push buttons only change their state while we are pressing, going back to its original state when the button is released.

Example 1

This is a basic functional example

This example works but, if you push for a long time, Arduino will detect more than one push and will switch the LED on or off.

// 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 buttonState = 0; // variable for READING the pushbutton status

int variable_buttonState = 0; // variable for STORING the pushbutton status

void setup() {

// initialize the LED pin as an output:

pinMode(ledPin, OUTPUT);

// initialize the pushbutton pin as an input:

pinMode(buttonPin, INPUT);

}

void loop(){

// read the state of the pushbutton value:

buttonState = digitalRead(buttonPin);

// check if the pushbutton is pressed.

// if it is, the buttonState is HIGH:

if (buttonState == LOW) {

// turn LED on:

variable_buttonState = !variable_buttonState;

//waiting time so we're not changing state several times with only push

delay(300);

}

if (variable_buttonState == HIGH) {

// turn led on

digitalWrite(ledPin, HIGH);

}

else {

// turn LED off:

digitalWrite(ledPin, LOW);

}

Example 2

Improved version with better 1 push detection.

With this second improved version, we use a variable to detect whether the push button was already pushed before, so we avoid multiple changes with one long press.