[Peter Randall]

The Charminator works by by applying a known force and measuring the amount of compression on the balls. We do this using a 3/4 inch pneumatic cylinder running at low pressure. Attached to the cylinder is a pull string connected to a constant force spring (manufactured by our primary sponsor Vulcan Spring). The spring is contained in a pull box to which we mounted a 1/4 inch output shaft that attaches to a US Digital Quadrature encoder. We tried both pull string potentiometers and linear potentiometers but did not get the reliable resolution necessary to classify the balls. The quad encoder give us highly repeatable measurements. The use of the Charminator slows down our shot rate somewhat, but greatly improves our accuracy especially at long distance. We wanted to be able to make shots from the far end of the field and the Charminator makes this possible.