There is little information about ATM direct drive equatorial mount. The only thing I can find is http://www.astrosurf...ives/index.html from a French gentleman. Two key pieces of the project seem to be the encoder and the motor. The encoder turns out to be Renishaw and the motor is made by an Italian company called Phase Motion Control. Apparently, the motor is rather special. It is a torque motor. All motors generate torque but torque motor is the one specifically designed to be operated in constant stalled or nearly stalled state, just like a tracking equatorial mount would do.
Sadly I don't have enough mechanical skill to take advantage of this information. Hopefully someone in the forum can and build a DIY direct drive mount!