Arduino Tutorial

By LiterallyTheOne

1: GPIO

Introduction

• Previous tutorial: blinking LED
• This tutorial: GPIO

What is GPIO?

• General Purpose Input/Output
• Input: We read from it
• Output: We write to it

GPIO Pins

• 14 Digital pins:
  • 0-13 (shown in red)
• 6 Analog pins:
  • A0-A5 (shown in yellow)

pinMode

pinMode(pin_number, mode);

• pin_number: number of the pin that we want to change (e.g., 13)
• mode: we can choose the mode of the pin; two of the choices are:
• INPUT: 0
• OUTPUT: 1

pinMode example

• pin 13 as output:

pinMode(13, OUTPUT);

• pin 3 as input:

pinMode(3, INPUT);

Add LED and Key

Setup

pinMode(13, OUTPUT);
pinMode(2, INPUT);

Variables

bool led_state = false;
bool button_pressed = false;

Logic

button_pressed = digitalRead(2);
if (button_pressed)
{
    led_state = !led_state;
    digitalWrite(13, led_state);
    delay(500);
}

Full code

#include <Arduino.h>

bool led_state = false;
bool button_pressed = false;

void setup()
{
  pinMode(13, OUTPUT);
  pinMode(2, INPUT);
}

void loop()
{
  button_pressed = digitalRead(2);
  if (button_pressed)
  {
    led_state = !led_state;
    digitalWrite(13, led_state);
    delay(500);
  }
}

Result

3 LEDs

Add another button

Link to the tutorial and materials