Thanks, Peter, very interesting.

Your work with ultrasound drivers is amazing! You saved me lots of months of try and error development. Now I feelk more confident than never to succeed in to build my own project.

Yes, my intention is to build a hacked USM motor from scratch based in the concept of travelling wave.

http://www.slideshare.net/sonalmaheshwari11/ultrasonic-motor-45023926

http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/spie-usm97.htm

I would need to modify your schematic and your code to manage a second function generator as theses motors need drivers with a second power output with a variable (about 90º) phase difference to reach its optimal performace.

Thanks for the like!

Since you do optics, you might like my other project: lasercut optics bench.

Also,  if you meant "ultrasonic piezoelectric motor", I've been toying with ideas on how to make them at the hacker level. I don't have time to pursue it right now, but I'd be happy to brainstorm.