I added a 2-stage pulley system for increased speed, and the roller goes swiftly, but the loop remains egg-shaped, holding a ~2:1 aspect ratio at high speed. I wonder if the loop is slipping against the roller. I need to find a way to measure the actual speed. My best idea so far is to build an optical counter, paint half the loop bright white ( Read more... )

http://www.newscientisttech.com/article/dn10673-acoustic-sensors-make-surfaces-interactive.htmlRead more... )