Unlike timer interrupts, external interrupts are triggered by external events. For example, when a button is pushed or you receive a pulse from a rotary encoder. However, just like the timer interrupts, you don’t need to keep polling the GPIO pins for a change. The Arduino UNO has 2 external interrupt pins. First, the button pin needs to be debounced. This can be done with the "blink-without-delay"-pattern where the button pin is sampled with a low period (40 ms in the example code below). Second, a simple state-machine is needed to keep track of the button state but also if the return button action function, doReturnButton(), has already been called.
Jul 25, 2014 · In this tutorial you will learn how to read the status of a digital pin of Arduino. I hope that you already go through our first tutorial, Getting Started with Arduino Uno – LED Blinking. In this example, a push button switch and an LED is connected to Arduino Uno. When we press the switch, LED will glow for 3 seconds. Button. Pushbuttons or switches connect two points in a circuit when you press them. This example turns on the built-in LED on pin 13 when you press the button. Hardware Apr 19, 2017 · To detect a short and long button press using millis can give your project more functionality without adding more buttons. In this line-by-line example, I show how to react to a user pressing a button for a short period (100ms) or a long period (over 500ms).