# US 8,772,724 B2 · Low power, inexpensive velocity detection using a PIR array > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,772,724 B2 - Document ID: US8772724B2 - Status: Granted - Kind: B2 - Application number: 12/984,713 - Filed: 2011-01-05 - Published: 2012-07-05 - Granted: 2014-07-08 - Earliest claimed: 2011-01-05 - Assignees: Intel-GE Care Innovations LLC - Applicants: William C. DeLeeuw - Inventors: William C. DeLeeuw - Web page: https://patentgrep.com/patent/US8772724B2 ## CPC - G01P 3/36: Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light (G01P3/68 takes precedence; gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams G01C19/64) - G01J 5/0025: {Living bodies (ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00)} - G01J 5/07: Arrangements for adjusting the solid angle of collected radiation, e.g. adjusting or orienting field of view, tracking position or encoding angular position (optical collimating elements G01J5/0806) - G01S 3/00: Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic or electromagnetic waves, or particle emission, not having a directional significance, are being received (position-fixing by co-ordinating a plurality of determinations of direction or position lines G01S5/00) - 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}) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract Methods and systems may include a system including a first passive motion sensor having a lateral field of view with a first edge and a second passive motion sensor having a lateral field of view with a second edge that is substantially parallel to the first edge. The first and second edges can define a virtual beam. The system may also include logic to receive signals from the first and second passive motion sensors and determine a gait velocity and level of activity based on the signals from the first and second passive motion sensors. ## Claims ### Claim 1 A method comprising: receiving signals from a first passive motion sensor and a second passive motion sensor, wherein the first passive motion sensor has a lateral field of view with a first edge and the second passive motion sensor has a lateral field of view with a second edge that is substantially parallel to the first edge, and wherein the first and second edges define a first virtual beam; and determining a gait velocity based on the signals from the first and second passive motion sensors. ### Claim 2 (depends on 1) The method of claim 1, further including: receiving signals from a third passive motion sensor and a fourth passive motion sensor, wherein the first and second passive motion sensors define a first sensor array having lateral field of view edges that define a first plurality of virtual beams, wherein the third and fourth passive motion sensors define a second sensor array having lateral field of view edges that define a second plurality of virtual beams, and wherein the first and second plurality of virtual beams partition an area into a plurality of zones; and determining a level of activity in each of the plurality of zones based on the signals from the first, second, third and fourth passive motion sensors. ### Claim 3 (depends on 2) The method of claim 2, further including: determining one or more orders of activation and one or more time differences based on the signals from the first, second, third and fourth passive motion sensors; and determining the gait velocity and the level of activity based on the one or more orders of activation, the one or more time differences, and one or more distances between virtual beam edges. ### Claim 4 (depends on 3) The method of claim 3, further including retrieving the one or more distances between virtual beam edges from a memory location. ### Claim 5 An apparatus comprising: a first passive motion sensor having a lateral field of view with a first edge; and a second passive motion sensor having a lateral field of view with a second edge that is substantially parallel to the first edge, wherein the first and second edges are to define a first virtual beam. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the first and second passive motion sensors are disposed horizontal to one another and the first virtual beam is to include a two-dimensional vertical beam, and wherein, if mounted to a wall of a hallway, the two-dimensional vertical beam is to be substantially perpendicular to a longitudinal axis of the hallway. ### Claim 7 (depends on 5) The apparatus of claim 5, further including a third passive motion sensor having a lateral field of view with a third edge, wherein the third edge is to further define the first virtual beam, and the first virtual beam is to include a substantially one-dimensional lateral beam. ### Claim 8 (depends on 5) The apparatus of claim 5, wherein the first and second passive motion sensors define a first sensor array, the apparatus further including a second sensor array having lateral field of view edges that are to define a second virtual beam. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the first sensor array further includes lateral field of view edges that are to define a third virtual beam and the second sensor array further includes lateral field of view edges that are to define a fourth virtual beam. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein, if mounted to a wall, the first, second, third and fourth virtual beams are to be positioned to partition an area into a plurality of zones. ### Claim 11 (depends on 5) The apparatus of claim 5, further including one or more leveling indicators. ### Claim 12 A system comprising: a first passive motion sensor having a lateral field of view with a first edge; a second passive motion sensor having a lateral field of view with a second edge that is substantially parallel to the first edge, wherein the first and second edges are to define a first virtual beam; and logic to, receive signals from the first and second passive motion sensors, and determine a gait velocity based on the signals from the first and second passive motion sensors. ### Claim 13 (depends on 12) The system of claim 12, wherein the first and second passive motion sensors are disposed horizontal to one another and the first virtual beam is to include a two-dimensional vertical beam, and, wherein, if mounted to a wall of a hallway, the two-dimensional vertical beam is to be substantially perpendicular to a longitudinal axis of the hallway. ### Claim 14 (depends on 12) The system of claim 12, further including a third passive motion sensor having a lateral field of view with a third edge, wherein the third edge is to further define the first virtual beam, and the first virtual beam is to include a substantially one-dimensional lateral beam. ### Claim 15 (depends on 12) The system of claim 12, wherein the first and second passive motion sensors define a first sensor array, the system further including a second sensor array having lateral field of view edges that are to define a second virtual beam. ### Claim 16 (depends on 15) The system of claim 15, wherein the first sensor array further includes lateral field of view edges that are to define a third virtual beam and the second sensor array further includes lateral field of view edges that are to define a fourth virtual beam. ### Claim 17 (depends on 16) The system of claim 16, wherein, if the first and second sensor arrays are mounted to a wall, the first, second, third and fourth virtual beams are to be positioned to partition an area into a plurality of zones. ### Claim 18 (depends on 16) The system of claim 16, wherein the logic is to, receive signals from the first and second sensor arrays, and determine a level of activity in each of the plurality of zones based on the signals from the first and second sensor arrays. ### Claim 19 (depends on 18) The system of claim 18, further including a memory, wherein the logic is to, retrieve one or more distances between virtual beam edges from the memory, determine one or more orders of activation and one or more time differences based on the signals from the first and second sensor arrays, and determine the gait velocity and the level of activity based on the one or more orders of activation, the one or more time differences, and the one or more distances between virtual beam edges. ### Claim 20 (depends on 12) The system of claim 12, further including one or more leveling indicators.