#define LED_BUILTIN 13. This indicates digital pin 13 on the Arduino's pins connector (also called a header). But at the same time LED_BUILTIN tells the Arduino to use the actual built-in LED on ...

An Arduino is a popular open-source single-board microcontroller. Learn how to program one and let the possibilities take shape. By The Big Book Of Hacks Published Jan 10, 2013 3:00 AM EST Get the ...

According to how long it stays in 5V and 0V (using the delay() function) you can obtain the fade effect. If delay() has a low value (for example 50ms or 0.05s) the fading speed will be higher because ...