metis wrote:iirc mouse rotary encoders don't have an index per se, they just have an understanding of + and - so if you get any outside forces that cause the wheel to skip a bit you'll suddenly be way off. it seems like there was a hack using legos adn a b&w disk to produce a pretty solid index though.... (is index the right term here?)
I think index is the correct term.
I'm not sure what the max rotational rate is for the iirc sensors(I didn't know that's what they were called by the way). Yes, they are only + and - but their should still be a fixed number of steps/rotation of the wheel, I believe the sensors are somewhat of an analog device so as long as the device reading the sensors can handle interupts at a fast enough rate, there should not be lost steps.
I think there are lost steps in mice because the cpu isn't fast enough. This could also be prototyped using hardware counters, I have a Xilinx Spartan 3e FPGA dev board at home.