Piezo based "Hula Hoop" motion screw thread driving actuators - capable of being very small http://www.newscaletech.com/squiggle_overview.html SQUIGGLE micro motor technology Patented piezoelectric motor with smallest size, high force and speed The heart of New Scale's M3 micro mechatronics module platform is the SQUIGGLE motor, a revolutionary linear micro motor with incredibly small size and big performance. This patented ultrasonic motor creates high force and speed with only a few parts - compare to complex electromagnetic gearhead motors with hundreds of parts. SQUIGGLE micro motors allow product designers to add motion features into products where they could not have been imagined before. This simple, robust piezo motor is scalable to much smaller sizes than electromagnetic motors, without significant loss of power efficiency. This makes it ideal for portable products such as micro cameras, medical devices and biometric detection systems. SQUIGGLE micro motor features Precise: nanometer resolution Fast: variable speed from 1 =B5m/second to 10 mm/second Strong: models with up to 5 Newton force Tiny: as small as 1.8 x 1.8 x 6 mm Quiet and smooth Non-magnetic, vacuum and cryogenic options available --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .