# US 9,435,821 B1 · Single-axis accelerometer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,821 B1 - Document ID: US9435821B1 - Status: Granted - Kind: B1 - Application number: 14/104,881 - Filed: 2013-12-12 - Granted: 2016-09-06 - Earliest claimed: 2013-12-12 - Assignees: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Applicants: The United States of America as Represented by the Administrator of the National Aeronautics and Space Administration - Inventors: Dennis Stephen Tucker; Pedro A. Capó-Lugo - Web page: https://patentgrep.com/patent/US9435821B1 ## CPC - G01P 15/09: by piezoelectric pick-up - H10N 30/852: {Composite materials, e.g. having 1-3 or 2-2 type connectivity} - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract A single-axis accelerometer includes a housing defining a sleeve. An object/mass is disposed in the sleeve for sliding movement therein in a direction aligned with the sleeve's longitudinal axis. A first piezoelectric strip, attached to a first side of the object and to the housing, is longitudinally aligned with the sleeve's longitudinal axis. The first piezoelectric strip includes a first strip of a piezoelectric material with carbon nanotubes substantially aligned along a length thereof. A second piezoelectric strip, attached to a second side of the object and to the housing, is longitudinally aligned with the sleeve's longitudinal axis. The second piezoelectric strip includes a second strip of the piezoelectric material with carbon nanotubes substantially aligned along a length thereof. A voltage sensor is electrically coupled to at least one of the first and second piezoelectric strips. ## Claims ### Claim 1 A single-axis accelerometer, comprising: a housing defining a sleeve having a longitudinal axis; an object having a mass disposed in said sleeve for sliding movement therein in a direction aligned with said longitudinal axis; a first piezoelectric strip attached to a first side of said object and attached to said housing, said first piezoelectric strip longitudinally aligned with said longitudinal axis, said first piezoelectric strip including a first strip of a piezoelectric material with carbon nanotubes substantially aligned along a length of said first strip; a second piezoelectric strip attached to a second side of said object and attached to said housing, said second side opposing said first side, said second piezoelectric strip longitudinally aligned with said longitudinal axis, said second piezoelectric strip including a second strip of said piezoelectric material with carbon nanotubes substantially aligned along a length of said second strip; and a voltage sensor electrically coupled to at least one of said first piezoelectric strip and said second piezoelectric strip. ### Claim 2 (depends on 1) A single-axis accelerometer as in claim 1, wherein said piezoelectric material is selected from the group consisting of polyvinilydene fluoride (P(VDF)) and polyvinilydene trifluoroethylene (P(VDF-TrFE)). ### Claim 3 (depends on 1) A single-axis accelerometer as in claim 1, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO3). ### Claim 4 (depends on 2) A single-axis accelerometer as in claim 2, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO3). ### Claim 5 (depends on 1) A single-axis accelerometer as in claim 1, further comprising a voltage source coupled to one of said first piezoelectric strip and said second piezoelectric strip. ### Claim 6 A single-axis accelerometer, comprising: a housing defining a sleeve having a longitudinal axis; an object having a mass disposed in and constrained by said sleeve for sliding movement therein only in a direction aligned with said longitudinal axis; a first piezoelectric strip attached to a first side of said object and attached to said housing, said first piezoelectric strip longitudinally aligned with said longitudinal axis, said first piezoelectric strip including a first strip of a piezoelectric material with carbon nanotubes embedded in and substantially aligned along a length of said first strip; a second piezoelectric strip attached to a second side of said object and attached to said housing, said second side opposing said first side, said second piezoelectric strip longitudinally aligned with said longitudinal axis, said second piezoelectric strip including a second strip of said piezoelectric material with carbon nanotubes embedded in and substantially aligned along a length of said second strip; and a voltage sensor electrically coupled to one of said first piezoelectric strip and said second piezoelectric strip. ### Claim 7 (depends on 6) A single-axis accelerometer as in claim 6, wherein said piezoelectric material is selected from the group consisting of polyvinilydene fluoride (P(VDF)) and polyvinilydene trifluoroethylene (P(VDF-TrFE)). ### Claim 8 (depends on 6) A single-axis accelerometer as in claim 6, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO3). ### Claim 9 (depends on 7) A single-axis accelerometer as in claim 7, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO3). ### Claim 10 (depends on 6) A single-axis accelerometer as in claim 6, further comprising a voltage source coupled to one of said first piezoelectric strip and said second piezoelectric strip. ### Claim 11 A single-axis accelerometer, comprising: a housing defining a sleeve having a longitudinal axis; an object having a mass disposed in and constrained by said sleeve for sliding movement therein only in a direction aligned with said longitudinal axis, wherein air spaces are defined in said sleeve on opposing sides of said object; a first piezoelectric strip attached to a first of said opposing sides of said object and attached to said housing, said first piezoelectric strip disposed in one of said air spaces and longitudinally aligned with said longitudinal axis, said first piezoelectric strip including a first strip of a piezoelectric material with carbon nanotubes embedded in and substantially aligned along a length of said first strip, said carbon nanotubes occupying approximately 30-50 volume percent of said first piezoelectric strip; a second piezoelectric strip attached to a second of said opposing sides of said object and attached to said housing, said second piezoelectric strip disposed in another of said air spaces and longitudinally aligned with said longitudinal axis, said second piezoelectric strip including a second strip of said piezoelectric material with carbon nanotubes embedded in and substantially aligned along a length of said second strip, said carbon nanotubes occupying approximately 30-50 volume percent of said second piezoelectric strip; and a voltage sensor electrically coupled to one of said first piezoelectric strip and said second piezoelectric strip. ### Claim 12 (depends on 11) A single-axis accelerometer as in claim 11, wherein said piezoelectric material is selected from the group consisting of polyvinilydene fluoride (P(VDF)) and polyvinilydene trifluoroethylene (P(VDF-TrFE)). ### Claim 13 (depends on 11) A single-axis accelerometer as in claim 11, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO3). ### Claim 14 (depends on 12) A single-axis accelerometer as in claim 12, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO3). ### Claim 15 (depends on 11) A single-axis accelerometer as in claim 11, further comprising a voltage source coupled to another of said first piezoelectric strip and said second piezoelectric strip.