Hey instructables, I haven't been on in a while but I am back and looking for someone to give me some advice. In my class, we are playing a castle crashers type game where we have to design a device that will remove all of the foam blocks from the area provided. I came up with an idea that utilizes air pressure to propel the net forward with a decent amount of force. However, I am running into an issue in finding a feasible way to store the pressure provided from me pumping a bike pump, and releasing it to propel the net. I was interested in using a rubber bladder to contain the air pumped into it, and releasing the air on command (start button). I can't use an actual compressor unit as it must be human or battery powered, and it must fit in a 2'x2' space and can't reach more than 5' tall. Any ideas as to where or how I might create a bladder would be greatly appreciated!