Angular DRO project to track lathe chuck position, speed, etc.
The small cup holds a microcontroller (Atmel 90S2313 AVR processor)
that decodes a quadrature encoder, an HP HEDS 5600 with 2000 states/rev.
and maintains a 4-digit display. Display modes are RPM, #turns, angular position, 
and a utility timer. Resolution with 1:1 gearing is 0.18 degrees.
Resolution of #turns is 0.01, but drops when count needs more digits.
Top tracking speed is 3000 rpm.
A matching gear was bored out and placed over the rear of the lathe spindle.