Introduction: Linkit One: Debounce Button

In this tutorial I will share on how to make a pushbutton as a toggle switch to turn on/off other pin

Step 1: Material & Setup

For this tutorial we will need minimum component:

  • Linkit one board
  • 1 LED
  • 1 push button
  • 1 Bread Board
  • 1 10K ohm Resistor
  • 3 Male to Male Jumper wire
  • Micro USB Cable

Make the connection just like in the picture. We will use Pin 2 as input and pin 13 as an output.

Install the Linkit One SDK using this Link

Step 2: The Code

Copy and paste the code below to the arduino IDE, then Upload it:


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. *

/ 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; }

Step 3: Test It Out

To test if the code is working well. Try to push the button once, it will turn on the LED. Then push it again one more time to turn off the LED.

If nothing happens try to press the button a little bit longer or check the connection