An asynchronous detection library for pushbutton click events.

Summary

This is a library for the Arduino IDE that helps listening to pushbutton click actions on an asynchronous and non-blocking way using callback functions.

It can handle short, long and double clicks.

It doesn't use delays, so it doesn't affect any other action on your code.

Important: Do not use delay() on your code, or the button handling may be affected.

Getting started

Use a normally-open momentary pushbutton connected to the pin you want to read. It uses digitalRead() to detect whether the button is released (LOW) or pressed (HIGH) to detect button actions.

How to use

Import the library:

#include <CallbackButton.h>

Create a CallbackButton object:

#define BUTTON_INPUT_PIN 5
CallbackButton callbackButton = CallbackButton(BUTTON_INPUT_PIN);

Create a function to be used as a callback (note the constants you can use for clickType values):

void onButtonClick(int port, int clickType) {
  // The port number and the detected clickType will be received as parameters.

  // Replace the code below with your own implementation.
  switch (clickType) {
    case CALLBACK_BUTTON_SHORT_CLICK:
      // SHORT_CLICK detected;
      break;
    case CALLBACK_BUTTON_LONG_CLICK:
      // LONG_CLICK detected;
      break;
    case CALLBACK_BUTTON_DOUBLE_CLICK:
      // DOUBLE_CLICK detected;
      break;
  }
}

Configure the port mode and the callback function in the setup() function:

void setup() 
{
  // Set the pin mode as INPUT. The lib won't do it on its own.
  pinMode(BUTTON_INPUT_PIN, INPUT);

  // Set the callback function, because it was not passed to callbackButton on the constructor.
  callbackButton.setCallbackFunction(onButtonClick);
}

In the loop() function, call the checkButtonState() method on the callbackButton instance:

void loop()
{
  callbackButton.checkButtonState();
}

Now every time the library detects any of its supported button click types (short, long or double click), the callback function onButtonClick will be called.

Note: The times for long and double clicks detection and the debounce time can be configured, check the other constructors and its parameters.

Check the examples folder for more working examples, including on how to listen to multiple buttons at once.