Resistive force sensing device and method with an advanced communication interface

• US 7,644,628 B2
• Filed: 06/04/2009
• Issued: 01/12/2010
• Est. Priority Date: 12/16/2005
• Status: Active Grant

• Current Assignee: Ypoint Capital, Inc,
• Original Assignee: Loadstar Sensors Incorporated (Ypoint Capital, Inc,)
• Inventors: Harish, Divyasimha
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US12/477,927
• Publication Number:
  US 20090234592A1
• Time in Patent Office: 222 Days
• Field of Search: 737/80, 738/626.26
• US Class Current: 73/780
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: G01L 1/2231 the supports being disc- or ring-shaped, adapted for measuring a force along a single direction
• CPC Class Codes: G01L 1/2243 the supports being parallelogram-shaped

Abstract

Several methods and a system of a resistive force sensing device and method with an advanced communication interface are disclosed. An exemplary embodiment provides a force measuring device. The force measuring device includes a resistive sensor having a fixed surface and a movable surface. A spring assembly is positioned between the fixed surface and the movable surface. The spring assembly alters in height in response to a force applied perpendicular to the movable surface and causes a change in a resistance of the resistive sensor. A circuit generates a measurement of the force based on an algorithm that considers a change in the resistance of the resistive sensor. A universal serial bus (USB) interface of the circuit provides digital output of the measurement to a computing device.

Claims

1. A force measuring device comprising:

a fixed surface and a movable surface;

a member positioned between the fixed surface and the movable surface, the member caused to deflect in response to a force applied to the movable surface and to cause a change in an electrical property of the force measuring device;

a circuit to measure the force based on an algorithm that considers the change in the electrical property of the force measuring device; and

a data processing module of the force measuring device to communicate a measurement through an advanced communication interface

the advanced communication interface is at least one of a Universal Serial Bus (USB) interface, a Bluetooth interface, a Zigbee interface, a WiFi interface, a WiMax interface, a Wibree interface, a RS-232 interface, a RS-422 interface, a RS-485 interface, an Ethernet interface and a Power over Ethernet interface,

means for applying an algorithm to convert a change in the electrical property to at least one of a voltage response and a frequency response to automatically generate the measurement, wherein the electrical property is at least one of a capacitance, a resistance, and an inductance;

the force measuring device is at least one of a pancake sensor and a S-beam load cell that provides the measurement when under at least one of a tension and a compression mode;

wherein when the force measuring device is the pancake sensor, the pancake sensor includes a contact zone cavity formed in a ring like fashion around a periphery of the movable surface, a conical washer between the fixed surface and the movable service, a female thread through the center and at least one hole on an outer ring to mount the pancake sensor to another assembly; and

wherein when the force measuring device is the S-beam load cell, the S-beam load cell includes a flexible strain relief material, and a reference spring between the fixed surface and the movable service, and at least one hole on an outer portion to mount the S-beam load cell to another assembly.