title: An umbilical data-acquisition system for measuring pressures between the foot and shoe.
abstract: We have developed an umbilical data-acquisition system for measuring pressures between the foot and shoe during walking. It consists of pressure sensors in the insoles of shoes, amplifier circuits, umbilical cables, an analog-to-digital converter, and a graphics display card in an IBM PC for real-time data collection and display. The applied pressure on a sensor decreases its resistance, which causes the output voltage of the amplifier circuit to increase. We attach seven sensors to the surface of each insole of a pair of extra-depth shoes and calibrate all the sensors in the insole before and after each test using a load cell as a reference. The IBM PC samples the outputs from the sensor and the load cell and stores a piecewise linear lookup table for use in compensation for the nonlinearity of the sensor. On the PC's graphics display, two programs provide displays of foot pressures as real-time bar graphs or as analog pressure versus time curves.
authors.affiliation: Department of Electrical and Computer Engineering, University of Wisconsin, Madison 53706.
authors.forename: H S
authors.initials: HS
authors.lastname: Zhu
authors.forename: N
authors.initials: N
authors.lastname: Maalej
authors.forename: J G
authors.initials: JG
authors.lastname: Webster
authors.forename: W J
authors.initials: WJ
authors.lastname: Tompkins
authors.forename: P
authors.initials: P
authors.lastname: Bach-y-Rita
authors.forename: J J
authors.initials: JJ
authors.lastname: Wertsch
mesh_terms: D000703:Analog-Digital Conversion; D001696:Biomechanical Phenomena; D005528:Foot / Q000502:physiology; D005684:Gait / Q000502:physiology*; D006801:Humans; D008838:Microcomputers; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D011312:Pressure; D012016:Reference Values; D012775:Shoes; D012985:Software Design