Accelerometer telemetry system

• US 3,972,038 A
• Filed: 03/28/1975
• Issued: 07/27/1976
• Est. Priority Date: 03/28/1975
• Status: Expired due to Term

• Current Assignee: Eph Konigsberg, Fletcher James C Administrator of The National Aeronautics and Space Administration With Respect To An Invention of
• Original Assignee: Eph Konigsberg, Fletcher James C Administrator of The National Aeronautics and Space Administration With Respect To An Invention of
• Inventors: Fletcher, James C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of, Konigsberg, Eph
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US05/563,049
• Time in Patent Office: 487 Days
• Field of Search: 340/189 M, 340/206, 73/493, 73/517 R
• US Class Current: 340/870.24
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/1101 Detecting tremor
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: G01P 1/07 Indicating devices, e.g. for remote indication indicating working conditions of vehicles G07C5/00
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges

Abstract

An accelerometer telemetry system incorporated in a finger ring is used for monitoring the motor responses of a subject. The system includes an accelerometer, battery and transmitter and provides information to a remote receiver regarding hand movements of a subject wearing the ring, without the constraints of wires. Possible applications include the detection of fatigue from the hand movements of the wearer.

Claims

1. A miniaturized accelerometer telemetry system for monitoring the hand movements of a subject comprising:

an accelerometer for detecting accelerational movements and for producing an electrical output signal in accordance therewith;

transmitter means;

modulator means for modulating the output of said transmitter with the output signal produced by said accelerometer;

a housing, adapted to be worn on the person, for housing said accelerometer, said transmitter means and said modulator means;

said accelerometer comprising an annular ring and a central support beam extending diametrically across said ring, a seismic mass affixed to said beam at the center of said ring so as to permit axial movements of said seismic mass, and first and second semiconductor strain gages, bonded to said beam on opposite sides of said mass, the electrical resistance of said gages varying in relationship to the stresses endured in each of said beams.

2. A miniaturized accelerometer telemetry system for monitoring the hand movements of a subject comprising:

as accelerometer for detecting accelerational movements and for producing an electrical output signal in accordance therewith;

transmitter means;

modulator means for modulating the output of said transmitter with the output signal produced by said accelerometer;

a housing, adapted to be worn on the person, for housing said accelerometer, said transmitter means and said modulator means;

said modulator means comprising a sample-and-hold circuit connected to the output of said accelerometer, multivibrator means for pulsing said accelerometer and said sample-and-hold circuit, and amplifier means for connecting the output of said sample-and-hold circuit to the input of said multivibrator means; and

said transmitter means comprising a pulse time modulation transmitter connected to an output of said multivibrator means.

3. A miniaturized accelerometer telemetry system for monitoring the hand movements of a subject comprising:

an accelerometer for detecting accelerational movements and for producing an electrical output signal in accordance therewith;

transmitter means;

modulator means for modulating the output of said transmitter with the output signal produced by said accelerometer;

a housing, adapted to be worn on the person, for housing said accelerometer, said transmitter means and said modulator means;

said accelerometer including a seismic mass, a mount for said mass, and at least one strain gage for detecting the strain endured in said mount responsive to movements of said mass and for producing an output signal in accordance therewith;

said modulator means comprising means for pulsing said at least one strain gage so as to produce a voltage proportional to the strain induced in said mount, means for storing said voltage, a constant current generator for producing an output that varies directly with the voltage stored by said storing means, an astable multivibrator for producing a pulse train of constant pulses, the interval between pulses in said pulse train being dependent on said output of said constant current generator; and

said transmitter means comprising means for producing radio frequency pulses responsive to the output of said astable multivibrator.

4. An accelerometer telemetry transmission circuit comprising:

an accelerometer for detecting accelerational movements and for producing an electrical output signal in accordance therewith;

a sample-and-hold circuit connected to the output of said accelerometer;

multivibrator means for pulsing said accelerometer and said sample-and-hold circuit, said multivibrator means including a control input connected to the output of said sample-and-hold circuit so that the output of said sample-and-hold circuit controls the interval between the pulses produced by said multivibrator means; and

a transmitter means connected to an output of said multivibrator means.

5. An accelerometer telemetry transmission circuit as claimed in claim 4 wherein said accelerometer comprises first and second resistive strain gages electrically connected to form a voltage divider, a point on the junction between said strain gages being connected to the input to said sample-and-hold circuit.

6. An accelerometer telemetry transmission circuit as claimed in claim 4 wherein said transmitter means includes radio frequency oscillator means for producing radio frequency pulses having a variable interval therebetween, the duration of said interval being controlled by the output of said multivibrator means, said transmitter means further comprising a coil which serves as the inductive element of the tank circuit of said oscillator and as the radio frequency radiator of said transmitter means.