Velocity Sensitive Drum Trigger from Old Headphones

Step 2 Cut a Hole in the Cassette Case

I decided to make a 1.5 inch square pad for the trigger. I added a 1/16 inch gap for the hole, and cut a square 1 and 5/8 inches into the cassette case. I liked the case because the two spindles give the pad more support.
I also cut a notch on the side of the case for the cord to fit out of.