The DuinoTagger and Talcapult

Like a ’70s cop team – one is the goodie two shoes and the other one is the drunk – the DuinoTagger and Talcapult allow you to shoot things and make smoke appear. The gun uses an Arduino board to control a tiny catapult that blows out a little puff of smoke.

The instructions are pretty detailed but you can see how it works here if you’re so inclined.