Design and implementation of expressive footwear

As an outgrowth of our interest in dense wireless sensing and expressive applications of wearable computing, the Responsive Environments Group at the MIT Media Laboratory has developed a very versatile human-computer interface for the foot. By dense wireless sensing, we mean the remote acquisition of many different parameters with a compact, autonomous sensor cluster. We have developed such a low-power sensor card to measure over 16 continuous quantities and transmit them wirelessly to a remote base station, updating all variables at 50 Hz. We have integrated a pair of these devices onto the shoes of dancers and athletes, measuring continuous pressure at three points near the toe, dynamic pressure at the heel, bidirectional bend of the sole, height of each foot off conducting strips in the stage, angular rate of each foot about the vertical, angular position of each foot about the Earth's local magnetic field, as well as foot tilt and acceleration, 3-axis shock acceleration (from kicks and jumps), and position (via an integrated sonar). This paper describes the sensor and electronics systems, then outlines several projects in which we have applied these shoes for interactive dance and the capture of high-level pediatric gesture. We conclude by outlining several applications of our sensor system that are unrelated to footwear.