Recently, we published an entry-level Arduino project with ... twelve (in place of thirty-two)! The LED segments of the display require current-limiting resistors when powered from a 5 V logic pin.

Did you know that you can use Arduino to turn on an LED when you press a button? Well, it is true, you can do this! Leaving the joke aside, let me show how you can achieve this. You will need the ...

You usually need a high precision resistor (1% or better) in series with the inductor, a function generator to put a signal through ... you pull it off with an Arduino and an LM339 quad comparator.

Let it hit your red LED and you’ve lost a point ... Inside the cool laser-cut box is an Arduino Uno and a 9V battery, plus a current-limiting resistor and the all-important buzzer.