Optical Encoder

Trackballs

Ultimarc Flush Mount

3" HAPP Trackball - these are standard in Golden Tee machines and thus, can often be found used for relatively cheap! Note: Will require an external control board such as an Optipac Will also likely require an external mounting plate such as this

2.25" HAPP Trackball - same as above, but in a smaller package! Cheaper to buy new, harder to find used. Will also require a control board and mounting plate.

Spinners

Spinners are effectively half a trackball! They will typically emulate a mouse on a single axis!