A touch controller is presented that comprises a touch sensor employing a resistive membrane, and an analog electronic circuit that accurately measures the touch position and the touch pressure on the sensor. Several variations of the electronic circuit are presented based on the principle of providing a constant current through the touch sensor, measuring the position with a differential amplifier, and measuring the touch pressure at the output of the current regulator. The touch sensors that may be used include resistive coatings such are used in overlays for computer displays, and force-sensing resistors. The circuits are simple, accurate and low-cost, yet provide measurements of the touch position that are fully decoupled from the pressure measurement, without approximation. The result is that the useful range of touch sensitivity is extended to include very light touches, without sacrificing position accuracy.
The invention provides a coordinates input device capable of detecting coordinates with high accuracy by eliminating errors that could be contained in detected voltage depending on the condition of the pressure applied to a coordinates input section. When pressure is applied to a plane resistive sheet of the coordinates input section, the maximum voltage applied to the coordinates input section is detected by means of an A/D converter prior to the detection of the coordinates, and correction is made by a reference voltage regulating circuit so that a reference voltage becomes equal to the maximum voltage. Thereafter, the A/D converter converts the detected voltage to digital data on the basis of the corrected reference voltage, for calculation of the coordinates. Errors that could be contained in the detected voltage when detecting the coordinates can thus be eliminated.
A touch panel device comprises a resistance material on which a potential gradient is formed extended along an X axis, a contact electrode to be pushed to contact with the resistance material, a potential supplying unit for selectively supplying to the contact electrode via a resistance via at least two kinds of potentials one by one, a potential detecting unit for detecting the potential at the contact electrode, and a pushed position detecting unit for detecting a X coordinate of the pushed position based on the potential detected by the potential detecting unit when the potentials are supplied thereto by the potential supplying unit.
A touch sensor with a sensor surface insulated with respect to ground potential, the sensor surface being connected via a measuring resistor to an a.c. voltage generator, and the voltage across the measuring resistor being used as a difference measuring signal. At least one touch sensor can advantageously be integrated in a sanitary fitting and used to control solenoid valves on water feeds of the fitting. An operating element of the fitting is used as a sensor surface and is connected via a connecting cable to control electronics of the sensor. A method of detecting a touch on an electrically conductive surface, a capacitive touch sensor being used which detects the complex conductance of a human body. The touch detection is carried out by measuring and evaluating a current flow in the direction from the sensor to the person who touches the sensor surface and/or in the direction from the person into the sensor.
A position sensing device having an insulating board, a first conductive sensing element, a second conductive sensing element, an oscillator, conductive material, a differential amplifier, and a processor. The first and second spaced conductive sensing elements are on the insulating board. The oscillator generates an oscillating signals and the conductive material is spaced from the sensing elements. The conductive material receives the oscillating signal to create an electric field between the conductive material and the first and second sensing elements. The differential amplifier includes differential inputs that are connected to the conductive sensing elements. The signal levels at the differential inputs vary based on the position of a pointing object of a user relative to the first and second conductive sensing elements. The processor generates a position signal based on an output of the differential amplifier.
When a pair of opposed resistance sheets of a pressure sensitive 3D tablet are pressed into contact with each other by a tablet manipulation, an equal current is applied to a reference resistor R.sub.C, and the position of contact (x.sub.p,y.sub.p) between both sheets and a first potential difference V.sub.A, based on the resistance value r.sub.C of the reference resistor R.sub.C and a second potential difference based on the contact resistance r.sub.p at the contact position, are detected. Since the contact resistance r.sub.p can be detected by r.sub.P =r.sub.C *V.sub.B /V.sub.A, the X- and Y-coordinates (x.sub.p) and (y.sub.p) and the contact resistance r.sub.p at the position of contact between the resistance sheets can be detected as 3D independent parameters.
