The three students in picture below, build a pressure pump that would build up pressure. They designed it on a CAD system, then they made the pistons, the push robs, crank and the sleeve for the pistons, a cap for the intake air and a cap for the out take air and it would build up pressure that you basically could fill up a balloon with.  It was not very strong but it did pretty good job.  All material were purchase from a hard ware store.  I was really impressed with their talent to get the job.  They won first place.