The present invention provides a touch control switch circuit capable of responding to coded touch inputs, i.e., touch inputs of different duration or particular sequences of touch inputs, to selectively control the operation of a load device. The touch control switch circuit is particularly useful for operating a household lighting fixture. The touch control switch circuit allows an operator to selectively control the intensity or timing of operation of the lighting fixture by applying predetermined touch code inputs to the circuit.
A touch-operation semiconductor switch is constituted by employing a switching device and a semiconductor negative resistance device comprising a complemetary connection of a depletion mode n-channel junction type field-effect transistor (hereinafter: FET) and a depletion mode p-channel junction type FET, both FETs being connected by source to source to each other, and by each gate to each drain of the other FET, and a touching terminal is connected to said common connected sources, so that the on-off state of the negative resistance device is inversed when the touching terminal is touched by human body.
A touch responsive power control system in which the majority of the signal processing functions are achieved through digital circuitry and includes a controllable pulse generator responsive to the change in capacitance caused by a human touch at a touch sensitive control point of the device to be regulated. The magnitude of the change in capacitance caused by the human touch is encoded in the form of the number of pulses contained in a pulse train or a series of pulse trains over a selected time period. The number of pulses is counted and digitally compared with a stored count. If the present count is different from the stored count, the stored count is adjusted and an error signal proportional to the difference between counts is supplied, after a sufficient interval, to a load driver which adjusts the power level supplied to the load from an electrical power source.
The position of an operator's finger on a transducing surface is used for controlling the level of utilization devices including theater lights controlled by an automated theater light control system. The transducing surface, which may be either an analog or a digital device, is elongated in shape and is immediately adjacent to an elongated display having individual light-emitting devices to indicate the level of the utilization device being controlled. Circuitry connected to the transducing surface produces a first signal to indicate when an operator's finger is present on the transducing surface, and it produces a second signal to indicate the position of the operator's finger on the transducing surface. The second signal is supplied to the display, and the first and second signals are supplied to the utilization devices.
