To create my Twang-O-Bang, I used two boards, a hinge and an elastic.
To hold it together, I put the screws in with some help from my dad. I tied the elastic on one end with a knot and on the other side with an eye hook.
To change the volume, you would have to put the Twang-O-Bang in a metal box or something metal that would make it loud when you pull the elastic.
To change the pitch of the Twang-O-Bang, you would have to move one board, which stretches the elastic. The farther you pull the elastic, the higher the pitch gets. The less you pull the elastic, the lower the pitch gets.