The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Nov. 07, 2000

Filed:

Nov. 03, 1998
Applicant:
Inventors:

Craig A Ayres, Lapeer, MI (US);

John A Ayres, Lapeer, MI (US);

Douglas Hall, Clarkston, MI (US);

Assignee:

Invotronics Manufacturing, Lapeer, MI (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01C / ; G01C / ;
U.S. Cl.
CPC ...
33361 ; 33352 ; 3335 / ;
Abstract

An compass having an electronic magnetic field sensor and an analog directional display is disclosed wherein a signal from the field sensor proportional to one component of the earth's magnetic field is alternated in polarity and integrated to produce a triangular waveform the frequency of which is proportional to the strength of that field component and wherein a triangular waveform having a frequency proportional to the second component of the earth's magnetic field is produced in the same manner. These values are used by a microcontroller to control an air-core gauge such that a disk with reference markings attached to the gauge remains positioned with one of the reference markings facing either magnetic or true north. A resistor ladder network is also connected in parallel to the inputs of the integrators and controlled by the microprocessor through a shift register in order keep the integrators out of saturation.


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