I'm working on my first hardware project, an SMS web app that will submit (via Arduino) a signal to press the buzzer at my apartment building. As such, my vocabulary might be way off.
That said, I think I need a "relay" to close the circuit at the buzzer and unlock the door.
The project is almost done, except for this last piece. How can I figure out what part to buy? How do I test it so I don't mess up my Arduino? I have a starter's kit but I've never used a multimeter, for example.