Editing Apple Mouse (section)

=== Quadrature Encoding System ===

The M0100 used quadrature encoding to track movement:

'''Components:'''
* Rubber-coated steel ball (22mm diameter)
* Two perpendicular rollers (X and Y axes)
* Two slotted encoder wheels
* Four infrared LEDs (two per axis)
* Four photodetectors
* Simple logic board with encoder chip

'''Operation principle:'''
# Ball movement rotates against spring-loaded rollers
# Rollers turn encoder wheels with radial slots
# Slots alternately block and pass infrared light
# Photodetectors generate two square waves per axis
# Phase relationship between waves indicates direction
# Pulse frequency indicates speed

'''Technical specifications:'''
* Resolution: 100 counts per inch (cpi)
* Maximum tracking speed: 10 inches/second
* Sampling rate: 100 Hz
* Quadrature states: 4 per slot