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 oscillator, ...

If you're looking for a fun electronics project to give a small fright to trick-or-treaters you can create a spooky blinking eyes setup where several sets of colored eyes blink randomly by ...

The Julia programming language is a horrible fit for a no-frills microcontroller like the ATMega328p that lies within the classic Arduino, but that didn’t stop [Sukera] from trying, and succeeding.