Dynamics & Vibrations: Spring Projectile Project

My group and I designed a game where a ping pong ball could be launched from a device to hit a dart board. Players gain points in the same manner as in darts. The device can move in the X and Y direction so the player could aim. The design is composed of a large rod which has a spring around it. The rod has one end with a block which is thicker than the spring. The rod goes through an enclosure which has small hole only big enough for the rod to come out of. On the other end the rod has a handle which screws on to it. The bottom part of the enclosure is then screwed to a base which allows it to aim in the X and Y direction.