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… ...

Make sure your Arduino board and port are selected from the connection popup menu at the top of the IDE's editor window. Blink does one thing — it blinks a built-in LED on the Arduino.

Like almost all Arduinos, has a built-in led – the green one on the left in the photo. And it has a pair of yellow leds – called TX and RX – to indicate traffic on the serial bus. Except, on the Micro ...