Flex-actuated Bistable Dome Sensor Videos
These two videos demonstrate a low resolution sensor prototype made from a row of 31 overlapping bistable domes (8 inches long) formed in .006 inch thick, 302 type stainless steel (sometimes used for spring mechanisms).
Please note: The functioning sensor only takes up about 1/3 of the middle of the visible device being flexed.
Each dome is wired to an LED which lights up when contact is made in the up position and goes out when in the down position (a few arent working). The sensor and contact wires are protected in a longer length of clear vinyl tubing (21 inches long) which also serves to contain the edge of the metal bistable dome row. A much thinner design is possible- see: shape sensor design example for flexible circuitry..
Video 1 (364k download) demonstrates the proportionality between the bend radius and the number of bistable domes that are on or off. It also demonstrates the sensors ability to indicate which direction from flat the sensor is bent. The switches have a tendency to group but a more uniformly constructed rows with better edge containment show a more even distribution.
Video 2 (420k download) demonstrates the sensors unique 2D capabilities. The bistable domes not only indicate how much, and in which direction from flat the sensor is bent, but where it is bent.
US Patent # 5563458. Apparatus and Method For Sensing Surface Flexure. (Old contact address).
barkingpo at earthlink.net