Human-machine interface apparatus
Capacitive touch-activated transducer system including a plurality of oscillators
Capacitive transducer Patent #: 4177421
ApplicationNo. 06/068664 filed on 08/22/1979
US Classes:307/116, Condition responsive307/652, Responsive to approach or passage of an object341/20BODILY ACTUATED CODE GENERATOR
ExaminersPrimary: Hix, L. T.
Assistant: Dwyer, James L.
Attorney, Agent or Firm
International ClassesG05G 9/00 (20060101)
G05G 9/047 (20060101)
G01D 5/241 (20060101)
G01D 5/12 (20060101)
AbstractAn electronic two-directional control apparatus responsive to the capacitance of an external object for generating two electrical outputs simultaneously referable as co-ordinates defining the position of an external object in relation to a control surface, four sensing electrodes of approximately equal capacitance symmetrically arranged into pairs of opposing sensing electrodes within a common plane and electrically insulated from one another whereby sensing electrodes define a control surface and whereby sensing electrode capacitances independently vary in response to the proximity of an external object thereto and are electrically connected to an electrical input in such fashion that only the positive portions of the oscillatory potential are equally applied to each sensing electrode; two pairs of resistors electrically connected to sensing electrodes for continuously receiving discharge currents originating from each pair of opposing sensing electrodes, respectively and whereby each discharge current is a function of corresponding sensing electrode capacitance; a detector circuit electrically connected to both pairs of resistors for simultaneously detecting both continuous discharge currents from each pair of resistors, detecting differences therebetween, and generating two electrical outputs respectively.The electronic two-directional control apparatus may be utilized in combination with a human body act on a universally rotatable mechanical control member for simultaneously generating two electrical outputs referable as co-ordinates defining the position of mechanical control member in relation to control surface.