Type 1 cam is a carotid shape with HS gear hub inserts.
It is used like a counterweight to make it easier to rotate and arm from vertical. I have a spreadsheet that shows how to calculate the shape.
It needs either pulley ridges to keep a 1/8" rope centered on it,
or sprockets for a segment of HS chain.
It has the usual 1/2" standard holes for mounting to Vex metal.
Inventor’s guide shows math for how the change in Gravitational PE of the arm mass is exchanged with the PE of the stretched spring,
by translation through the shape of the cam.
Type 2 cam is trip-hammer escapement type, similar but more optimized and slipperier than the 1/2 circle with offset center cam that “Bomb Squad” uses for their catapult in the Dallas Anatole exhibition. One geared up motor can rotate the cam to push the short end of a springed lever gradually from min-cam-diameter to max-cam-diameter, then release it suddenly from max to min.
Posted to Vex CAD section, since it is HW solution, not SW.
This method allows well balanced “weightless arms” using a cam, such as an offcenteraxle small vex wheel with inside-out-tire, and a spring, such as latex tubing or rubber bands.