My father made me one about 35 years ago. He used two 2x2's about 3' long. He nailed the two together (about 2.5 inches from one end) with one 16 penny nail, so the 2x2's looked like wooden scissors. Then about middle way down each 2x2's he nailed two 8 penny nails (didn't nail all the way through and cut the nail heads off), which offset each other on the 2x2's. The 8 penny nails held the springs of the trap, while I would sit on the top 2x2, causing the springs to compress.
The 2x2's also served well as a dispatching tool for the foot traps.