Hello, I'm really new to building circuits, and I need some help with an idea I have. I read in a book that a high pitched siren is hard to locate, the sound seems to come from everywhere. How could I build a Circuit that could activate a toy siren via a timer of some sort, lets say after 30 mins, and then shut it off after the siren has sounded for 30 seconds. The siren could be hidden in a classroom, go off and make everyone jump, and then be retrieved at a later time.

Thanks!

 

You will want to read up on timing circuits. "Monostable multivibrator" will be a good internet search term for you to use.

When (not if) your teacher catches you, make sure you say you got help from William Beatty's website and don't mention this one!

 

Thanks a lot!