Detailed plans on the ghost trap and the pedal can be found here on http://www.gbfans.com/equipment/plans/ Sean’s plans are particularly helpful in understanding the build process. Stefan’s plans give a detailed overview of the trap to scale, so you can get your measurements spot on.
http://www.gbfans.com/community/viewtopic.php?f=3&t=28716 this thread details some of the best trap build threads, definitely worth reading through and checking out. The list also outlines what trap has been made out what material so if you’re building from a specific material, you can find hints and tips to help your build.
Aluminium side plates really add a touch of industrial and reality to a trap, it makes it look like a real piece of technology. You can find sellers on the for sale section on GBFans who offer laser cut plates. A cheap alternative is to use door push plates and cut them down to size.
Your trap doors don’t have to open. If your trap is being built for a belt hanger, it’s advisable to make them one solid piece.