Hello World

Let’s begin the journey with a simple blinking LED program, it’s a simple Arduino sketch which could be considered as the “Hello World!” of Internet of Things. While simple the “Hello World!” program is very important in that it’s a way of verifying the developing environment is set up correctly.

What we will need:

• Arduino Uno board
• Arduino IDE installed
• Micro USB cable

Arduino Uno Board

The Arduino IDE comes pre-loaded with a vast selection of sketches to get things moving, and so there is already a sketch to do exactly what we want and it is called Blink. It can be found under the Basics Built-In Examples.

Loading a preloaded blink sketch

I have also updated the sketch to use millis() instead of delay() since delay() actually pauses the program which is not what I wanted to do. The final Blink sketch will look as follow:

static void SetLedState(bool state)
{
    if (state)
    {
        digitalWrite(LED_BUILTIN, HIGH);
    }
    else
    {
        digitalWrite(LED_BUILTIN, LOW);
    }
}

void setup()
{
    pinMode(LED_BUILTIN, OUTPUT);
    digitalWrite(LED_BUILTIN, LOW);
}

void loop()
{
    unsigned int secondsSinceBoot = millis() / 1000;

    if (secondsSinceBoot % 2 != 0)
    {
        SetLedState(true);
    }
    else
    {
        SetLedState(false);
    }
}

After that, all that’s needed to be done is connect the USB cable, set the correct COM port and load it onto the Arduino Uno.

Blink sketch demo