Precision inclinometer with digital numerical readout
First Claim
1. An inclinometer providing a numerical readout, comprising:
- a housing in the form of a parallelepiped having first and second surfaces orthogonally disposed,passive power supply means for providing a plurality of essentially constant equivalue output voltages of opposing polarity from a single source potential,sensor means mounted to said housing, responsive to the influence of terrestrial gravitational force and disposed for gravity responsive output as a function of orientation of at least one of said surfaces relative to a reference axis,amplitude stabilized alternating current signal means non-inductively coupled to said sensor means for energizing said sensor means to provide a signal representing the sense and magnitude of inclination of said sensor with respect to said reference axis,detector means synchronously coupled to said alternating current signal means and said sensor means for providing a signal coincident in phase with said alternating current signal means when said sensor means is inclined with respect to said reference axis, andnumerical indicator means, coupled to said detector means for providing a numerical output proportional to said inclination when said inclination is within a predetermined angular range, and for blanking said numerical output when said angular range is exceeded.
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Abstract
An inclinometer providing a digital numerical readout includes a level sensor responsive to orientation and means for driving a liquid crystal display to indicate the inclination of a surface with a high degree of precision. Features include high stability with changes in battery voltage and surrounding temperature, a battery condition monitor, freedom from operational adjustments after the initial calibration, and partial blanking of the display to alert a user that the linear inclination limit has been reached. The direct reading digital readout permits ease of operation and a high degree of accuracy and repeatability. Circuitry is especially adapted for low power consumption.
47 Citations
15 Claims
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1. An inclinometer providing a numerical readout, comprising:
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a housing in the form of a parallelepiped having first and second surfaces orthogonally disposed, passive power supply means for providing a plurality of essentially constant equivalue output voltages of opposing polarity from a single source potential, sensor means mounted to said housing, responsive to the influence of terrestrial gravitational force and disposed for gravity responsive output as a function of orientation of at least one of said surfaces relative to a reference axis, amplitude stabilized alternating current signal means non-inductively coupled to said sensor means for energizing said sensor means to provide a signal representing the sense and magnitude of inclination of said sensor with respect to said reference axis, detector means synchronously coupled to said alternating current signal means and said sensor means for providing a signal coincident in phase with said alternating current signal means when said sensor means is inclined with respect to said reference axis, and numerical indicator means, coupled to said detector means for providing a numerical output proportional to said inclination when said inclination is within a predetermined angular range, and for blanking said numerical output when said angular range is exceeded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An improved circuit for a portable inclinometer of the type having an internal battery energized power supply, a gravitational sensor for providing an output signal responsive to an inclination thereof, an ac excitation signal for said sensor, and a digital display, wherein the improvement comprises:
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active voltage divider means for receiving current and a single unregulated supply voltage from said battery and providing substantially equal dc output voltages of opposing polarity with respect to a common ground to first and second terminals, means in the form of a unitary transistor switch responsive to a source of alternating voltage and to one of said dc output voltages, for providing a first component of said ac excitation signal at a predetermined frequency, phase, and amplitude, phase inverter means for providing a second component of said ac excitation signal 180°
out of phase with said first component, at said predetermined frequency and said amplitude, responsive to said source of alternating voltage,non-inductive means for differentially coupling said first and second ac signal components to energize said gravitational sensor, demodulator means in the form of a unitary transistor switch coupled to said output signal of said sensor, phase synchronized with said source of alternating voltage, for providing a dc signal responsive to said inclination, analog-to-digital converter means, responsive to said dc signal, for transforming said signal in analog form to an equivalent signal in binary digit form, and display driver means coupled to said converter means and responsive to said signal in binary digit form, for energizing said digital display when said inclination is within a predetermined range, and for blanking said display when said inclination exceeds said predetermined linear range. - View Dependent Claims (15)
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Specification