Read regular Rotary Encoder
This sketch can also be used for motors with Hall sensors
Interrupts:
Board int.0 int.1 int.2 int.3 int.4 int.5
Uno, Ethernet 2 3
Mega2560 2 3 21 20 19 18
For two Hall Sensors / two Motors / two Rotary Encoders a Mega2560 or Teensy 3.1 is needed!
J.Bruegl, June 2015