A glove has been instrumented to sense the angles of finger joints via the electrical resistances of strips of an electrically conductive elastomer on the backs of the fingers, including the thumb (see figure). The conductive elastomer is a urethane-based synthetic rubber filled with conductive carbon particles.
One end of each conductive elastomeric strip is connected to the tip of a digit through an elastic band. The other end of the strip is attached to the base of the digit through another elastic band. Each conductive elastomeric strip is routed through a plastic cylinder (not shown in the figure) that prevents the strip from rolling off the back side of the affected digit when the digit is bending.
The electrical resistance of each strip decreases when the strip is stretched by increased bending of the joints on the digit. Wires connect the ends of the strips to simple instrumentation amplifiers. The outputs of these amplifiers are voltages indicative of the resistances of the strips and thus the angles of the joints.
The glove is a prototype of a sensor apparatus for providing hand-configuration feedback for an interactive virtual-reality or other display system. In comparison with other instrumented gloves and glovelike exoskeletal devices developed previously for the same purpose, this glove costs much less. Elastomeric sensors based on the same principle might also be used to measure bending of arm and leg joints and to measure stretching and bending of other body parts.
This work was done by Larry C. Li, Fredric Dawn, and Todd A. Pesek of Johnson Space Center. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com under the Electronic Components and Circuits category, or circle no. 153 on the TSP Order Card in this issue to receive a copy by mail ($5 charge).
This invention is owned by NASA, and a patent application has been filed. Inquiries concerning nonexclusive or exclusive license for its commercial development should be addressed to
the Patent Counsel, Johnson Space Center; (713) 483-4871.
Refer to MSC-22513.