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.
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