Simple, Low-Cost Tracking with Active Magnetic Tags


The Atmosphere installation presents a large cloud of information on a wide presentation screen that can be manipulated by three handheld devices mounted on plinths within the gallery space. The visitor takes one of the devices and physically moves it within a designated area, thereby manipulating the information presented both on the screen and the larger projection. A simple magnetic coupling system was developed to track the position and orientation of the handheld device. Signals are magnetically coupled into these tags from transmitting coils on each plinth. The magnitude of the coupling is inversely proportional to the distance from the coils and proportional to the sine of the angle between the tag and the normal of the coil. Using the magnitude of the recovered signal from each tag for each coil, it is possible to calculate both the position and (unsigned) orientation of the device relative to the reference frame formed by the coils. Atmosphere is a collaboration of the Aesthetics and Computation group, the Responsive Environments group, and Steelcase Inc.