Using a Plunger System to Launch Balls

[HFCHS-NASA]

Our team was thinking of using a plunger system to launch balls. The balls would be loaded into a barrel, which is open at one end and has a plunger-type device on the other. Then, a motor pulls the spring-loaded plunger to a specific distance depending on how far we want to shoot the ball (think of a pinball machine). Anybody else thinking of going this route? We would use linear encoders or an ultrasonic sensor to sense how far back the plunger is pulled.