Daniel A Dwyer

US Patent:

20140145711, May 29, 2014

Filed:

Nov 26, 2012

Appl. No.:

13/685287

Inventors:

Eric Burdette - Newmarket NH, US
James M. Bailey - Concord NH, US
Daniel S. Dwyer - Auburn NH, US
Jeff Eagen - Manchester NH, US
Glenn A. Forrest - Bow NH, US
Christine Graham - Bow NH, US
Eric Shoemaker - Pembroke NH, US
P. Karl Scheller - Bow NH, US

International Classification:

G01B 7/14

US Classification:

32420711

Abstract:

A circuit to detect a movement of an object includes a magnetic field sensing element for generating a magnetic field signal proportional to a magnetic field associated with the object and a motion detector to generate a motion signal indicative of the movement of the object. The motion detector includes a peak identifying circuit to provide a peak signal and a peak sample selection module that selects a sample associated with one or more prior cycles of a magnetic field signal to generate a selected peak signal. The motion detector further includes a threshold generator to generate a threshold signal as a function of the selected peak signal and a comparator to compare the threshold signal with the magnetic field signal to generate the motion signal. Peak samples from prior magnetic field signal cycles may be averaged for use to establish the threshold signal. A method associated with the circuit is also described.