Has anyone tried to build a servo system using an electric scooter motor? They are 24VDC brushed motors that can turn up to 2500RPM. I understand the dynamics will be limited because of the rotor inertia, but it might be the next step in the evolution of low cost machines. $30/axis plus only one H bridge to build might be pretty good thing. Has anyone used magnetic encoders and a microcontroller as the feedback mechanism before. I have 10TPI leadscrews, so I think I may still have plenty of resolution left. All thoughts appreciated.