There's a big asterisk on the "absolute encoder" thing. It's still a relative encoder, but it includes it's own counter. It's nice not to have to implement a counter on the rio, but you would still have the problem of the zero changing every time you start up the robot. An actual absolute encoder would give the proper reading no matter how often the sensor had been turned off and moved. (see page 22 of the encoder user guide here:
http://content.vexrobotics.com/vexpr...User-Guide.pdf)
I'm wondering - do the rules allow us to power the encoder from a separate 5V battery that we could leave on all the time (even when the main battery is removed)?