Online. The Testing device Page Published on Wednesday, November 20, 1996 by Gideon Ariel The Testing Device Data was obtained from passive marker systems using a device that supported seven markers. This device was built by Dr. Richards utilized in the study of commercially available systems presented at the 3D conference on Human Movement at Chattanooga, Tennessee, July 3rd, 1998. Reference: /topics/comparison/testing_device.htm