Abstract: The position sensor constitutes a fixed planar board having disposed on the surface serpentine coil structures of relatively low resistance and inductance. The coils are driven in a resonance mode which provides a frequency output according to the position of a moving planar member. The second movable planar board has disposed on the surface thereof planar loop coil structures. The second board is moved in proximity to the first board to vary the resonance characteristics of the first coil according to the position of the second board with respect to the fixed board. In this manner the frequency output of the system is a function of the position of the boards with respect to one another. Other embodiments depict means for compensating the thermal drifts of the frequency with respect to temperature.

Abstract: There is disclosed a digital enhancement circuit which responds to the complementary inductance provided by a planar coil sensor which inductance varies in a complementary manner according to the position of a movable member associated with the planar coil configuration. The complementary inductance is coupled to an oscillator whereby the period of the oscillator is varied in a first mode according to a first inductance value and in a second mode according to a second inductance value. These signals are then processed by means of digital processing circuitry to develop a signal indicative of the difference of the periods as divided by the sum of the periods. This signal is a ratiometric signal, and by employing digital counters, one can provide an output signal having a predetermined gain factor and having the above noted ratiometric characteristic which signal is indicative of the position of the movable member as further enhanced by the gain factor.

Abstract: There is disclosed a key which is particularly adapted for use in a musical keyboard. The key includes a top pivotable member which acts as a key surface and which is pivoted to move with respect to a reference plane. The key contains on a bottom surface a magnetic field effecting member. Located beneath the key on the reference plane is a rigid board containing a planar coil configuration. As the hinge member is moved towards the rigid board, the member affects the magnetic field of the planar coil configuration to vary the inductance as well as the magnetic coupling in other arrangements. A plurality of such keys are employed as the keys in a musical keyboard and are associated with frequency determining circuits such as oscillators to provide output frequencies necessary for the control of music.

Abstract: A series of rotary sensors are disclosed. Each sensor consists of a drive coil which is a planar coil configuration separated from a sensing coil which is parallel to the drive coil. Interposed between the drive and sensing coils is a rotatable plate fabricated from a material capable of blocking a magnetic field induced in a drive coil from reaching or activating the sensing coil. The rotatable plate is shaped to allow predetermined amounts of flux to couple from the drive coil to the sensing coil as the plate is rotated. The shape of the plate therefore determines the signal provided at the sensing coil to enable one to provide such signals indicative of the angular movement of the plate between wide limits as from zero to 360.degree.. Other configurations utilizing a plurality of drive and sense coils and special shaped plates provide sine and cosine outputs as well as enable one to determine the quadrant of operation.

Abstract: An electronic bathroom scale employs a low profile planar coil position sensor which responds to the positioning of a pivotable lever system. The levers are coupled to a platform which moves in the vertical direction as a weight is placed upon the top or supporting platform of the scale. The sensor provides variable amplitude or frequency proportional to the weight on the scale. The output signal is processed so that a direct reading of the weight is displayed by means of a digital display. The circuitry described serves to compensate for the nonlinearity of the transducer while further providing other compensation to eliminate environmental effects such as temperature and other factors from affecting the direct display of weight.

Abstract: A planar coil apparatus is disclosed for providing an output signal indicative of a movement between at least a first and a second position. A first stationary planar member has disposed on a surface, a first flat coil configuration which is emplaced thereon by a printed circuit or similar technique. Located adjacent to this coil on the board is a second coil of similar configuration. A drive signal such as that obtained from an AC or pulse source is applied to the input terminals of one of the coils which constitutes the drive coil. A second planar board is positioned relatively congruent and above the first board and has located thereon a closed coil configuration which constitutes a closed coil loop. As this movable board is brought into proximity with the stationary board, magnetic flux is coupled via the loop from the drive coil to the second coil which serves as the sense coil.

Abstract: There is disclosed a displacement transducer which comprises a plurality of planar circuit boards, each having a coaxial central aperture. Each of said boards having disposed thereon at least one spiral conductive structure which manifests a predetermined coil. The structure is oriented about the aperture and has a first and second terminal. The boards are positioned in a stacked array with each of said boards separated one from the other and with said central apertures aligned to form a central coaxial cavity. Leads are coupled to the first and second terminals of said boards for connecting certain ones in a primary winding configuration and others in at least two secondary configurations. A magnetic core adapted for insertion into said cavity varies the coupling between the primary and secondary windings according to the depth of insertion of said core within said cavity.

Abstract: There is disclosed an electronic scale which may, for example, be used as a bathroom scale, medical room scale, or otherwise. The scale provides a digital display of the weight of an object placed or positioned on a weighing platform and can provide said display in terms of the conventional system or the metric system by varying the time base or gate as applied to a counter. The counter has another input which provides a frequency related to the object's weight; which frequency is counted in accordance with the duration of the time gate, to enable a digital display of the weight.Apparatus is shown for providing a time base for the scale and employs two voltage to frequency converters, one to provide a frequency related to the weight of an object and the other to provide a time base; both of which vary according to supply fluctuations. The circuitry provides a number of pulses to the counter indicative of the true weight and independent of the supply voltage.

Abstract: A beam type transducer of the type activated by a push rod, which rod is secured to a thin silicon diaphragm including a shallow deflection area determining depression. The rod is secured to the silicon diaphragm within the depression and is surrounded by a glass plate. The glass plate has a central accommodating aperture for insertion of the rod therethrough and has a spherical depression ground on a surface and of a diameter relatively equal to the diameter of the depression in said silicon. The glass plate is bonded about its periphery to cover the silicon diaphragm with the spherical depression facing the depression in the silicon. The rod is bonded to the silicon and directed through the aperture in the glass. Immediately below the aperture in the glass and encircling the rod is a cylindrical member which acts as a negative over pressure stop. The other end of the rod is coupled to a beam for application of a force thereto.

Abstract: There is disclosed an electronic scale which may, for example, be used as a bathroom scale, medical room scale, or otherwise. The scale provides a digital display of the weight of an object placed or positioned on a weighing platform and can provide said display in terms of the conventional system or the metric system by varying the time base or gate as applied to a counter. The counter has another input which provides a frequency related to the object's weight; which frequency is counted in accordance with the duration of the time gate, to enable a digital display of the weight.Apparatus is shown for providing a time base for the scale and employs two voltage to frequency converters, one to provide a frequency related to the weight of an object and the other to provide a time base; both of which vary according to supply fluctuations. The circuitry provides a number of pulses to the counter indicative of the true weight and independent of the supply voltage.

Abstract: An economical scale is disclosed which utilizes a cantilever beam having positioned thereon a transducer arrangement. The beam is coupled to a platform by means of a rod inserted into an aperture in a linear bearing; thus providing a force only in the axial direction, to enable the weighing of an object positioned at any location on the platform, with extreme accuracy.

Abstract: A beam transducer of the type activated by a push rod secured to a thin silicon diaphragm including a shallow deflection area determining depression. The rod is secured to the silicon within the depression and is surrounded by a plate of glass having a central rod accommodating aperture and secured to the silicon to generally cover the depression with the rod extending through the aperture in the glass. One end of the rod is coupled to a diffused beam for application of force thereto. Large forces as applied to the diaphragm and hence, the rod and the beam are limited when the silicon is caused to contact the glass plate and is stopped by the plate and according to the depth of the depression.