This instruction is executed only one time. Next is the loop function that sets the pin 13 HIGH (+5V on pin 13), waits a second (1000 ms), then turns OFF the LED (0V on pin 13) and waits another ...

It is a pretty common first project to use an Arduino (or similar) to blink an LED. Which, of course, brings taunts of: you could have used a 555! You can, of course, also use any sort of oscillato… ...

When you read “Arduino wristwatch”, you fall into the trap of envisioning an Arduino UNO clumsily strapped to someone’s wrist. [Marijo Blažević’s] creation is much more poli… ...