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.
Patent No.:
Date of Patent:
Sep. 22, 1987
Filed:
Apr. 17, 1986
Wayne A Bonin, Cedar, MN (US);
Roger D McCumber, Minnetonka, MN (US);
Rein S Teder, Minneapolis, MN (US);
Vericom Corporation, Minnetonka, MN (US);
Abstract
A capacitive accelerometer system for detecting changes in G-forces and for producing a digital count value proportional to such changes. An oscillator-driven capacitive transducer of a unique design produces a voltage variation whose amplitude and frequency characteristics are a function of the direction and magnitude of the applied G-forces. The transducer itself comprises a pair of spaced-apart parallel plates disposed on opposite sides of a beam-supported movable plate which responds to changes in acceleration forces. The modulated signal is then demodulated and applied by a semiconductor switch actuated by a pulse from a microprocessor to a voltage-controlled current source. The current source varies the discharge rate of a precision capacitor. When the voltage on the capacitor drops to a predetermined threshold, an interrupt signal is presented to the microprocessor which had been counting one microsecond pulses from its internal clock during the period between the actuation of the semiconductor switch and the generation of the interrupt. The count is then inversely proportional to the shift in capacitance of the transducer which, in turn, is proportional to the G-forces applied to it.