This is a robotic pedometer tester I designed to perform battery life studies on the Nike+ pedometer pod.  This pod is worn in a special pocket in the instep of a sport shoe.  The pod connects to a host device such as an iPhone or iPod Touch via Bluetooth.  The pod uses a piezoelectric diaphragm as an accelerometer to measure the force, direction, and duration of the runner's footfall.  I noticed that the Nike+ pod was quite intelligent in distinguishing between forward motion and walking in place.  The pod was able to filter walking or running in place and not advance the pedometer mileage.  I had to study movies of my own footfall in order to get the force, direction, and timing correct so as to simulate walking and running.

Here is a movie of the tester in action:  http://youtu.be/_IdQed__e7s