An automatic soda can crusher can be built at home using readily available supplies from most hardware stores, including PVC piping, PVC cement, a 3/4-inch steel pipe, a washing machine hose and some power tools. Lumber, screws and compressed air is also required.
With a 3/4-inch drill bit, create a hole in the center of a 2-inch PVC end cap. Glue the end cap onto a 2-inch PVC pipe.
Remove the clamp from a washing machine drain hose adapter, and attach the rubber fitting over one end of the steel pipe, wide end down. Wrap with electrical tape. Insert a 3/4-inch steel pipe into the PVC pipe and out of the drilled hole in the end cap. Cut the steel pipe so that just 6 inches is visible outside the PVC pipe. Glue a 3/4-inch end cap to the other end of the PVC pipe.
Glue a 1 1/2-inch PVC coupler to the bottom of the PVC pipe. Drill through the pipe and coupler and attach a 3/8 by 3-inch nipple. Measure the length of the piston when extended, and add 6 inches. Cut 3 lengths of lumbar to this size.
Arrange the lumber in a "U" shape (two boards standing up with the third on top). Screw together. Cover one of the open sides with additional wood. Drill a hole in the center of one side to feed the air hose. Attach the piston crusher to the box to complete the project. Video tutorials are available at Hackaday.com.