# US 11,029,757 B1 · Detecting positions of magnetic flux sensors having particular locations on a device relative to a magnetic field generator located at a predetermined position on the device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,757 B1 - Document ID: US11029757B1 - Status: Granted - Kind: B1 - Application number: 16/729,929 - Filed: 2019-12-30 - Granted: 2021-06-08 - Earliest claimed: 2015-09-24 - Assignees: Facebook Technologies, LLC - Applicants: Facebook Technologies, LLC - Inventors: Ke-Yu Chen; Sean Jason Keller; David R. Perek; Tristan Thomas Trutna; Bruce A. Cleary, III - Web page: https://patentgrep.com/patent/US11029757B1 ## CPC - G06F 3/014: {Hand-worn input/output arrangements, e.g. data gloves} - G01B 7/004: for measuring coordinates of points - G06F 3/017: {Gesture based interaction, e.g. based on a set of recognized hand gestures (interaction based on gestures traced on a digitiser G06F3/04883)} - G06F 3/0346: with detection of the device orientation or free movement in a three-dimensional [3D] space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A wearable device (such as a glove or other control adapted to be worn on a portion of a body) includes multiple magnetic field generators at various locations on the wearable device and a magnetic flux sensor at a predetermined position relative to the wearable device. A position determines spatial positions of locations of the wearable device based on magnetic fields generated by various magnetic field generators and detected by the magnetic flux sensor. In some embodiments, the magnetic field generators have known positions relative to each other. Additionally, each magnetic field generator may generate a magnetic field in response to an input signal having a particular attribute, allowing the magnetic flux sensor to identify magnetic fields generated by different magnetic field generators. ## Claims ### Claim 1 A device comprising: a magnetic field generator located at a predetermined position on the device, the magnetic field generator configured to generate a modulated magnetic field that is fixed in relation to the device; a plurality of magnetic flux sensors located at particular locations on the device, the particular locations on different fingers of a user of the device, each magnetic flux sensor configured to: (1) generate a demodulated signal based on detecting the modulated magnetic field at the particular location, (2) detect a strength and a direction of the demodulated signal, and (3) generate an output signal based on the detected strength and the detected direction of the demodulated signal one or more inertial measurement units (IMUs), each IMU being configured to generate a signal for an angular orientation of a particular magnetic flux sensor of the plurality of magnetic flux sensors, the particular magnetic flux sensor located on a finger of the user; and a position analyzer coupled to each of the plurality of magnetic flux sensors, the position analyzer configured to determine spatial vectors representing a position of each magnetic flux sensor relative to the magnetic field generator, wherein: the position of a magnetic flux sensor relative to the magnetic field generator is based on demodulating an output signal generated by the magnetic flux sensor, and the position analyzer is configured to determine further positional information for at least some of the plurality of magnetic flux sensors located on the fingers of the user based on the signal generated by the one or more IMUS. ### Claim 2 (depends on 1) The device of claim 1, wherein the magnetic field generator comprises one or more electromagnets. ### Claim 3 (depends on 2) The device of claim 2, wherein each magnetic flux sensor includes a measurement circuit configured to extract a magnetic field having a certain frequency. ### Claim 4 (depends on 3) The device of claim 3, wherein different magnetic flux sensors include measurement circuits configured to extract magnetic fields having different frequencies. ### Claim 5 (depends on 1) The device of claim 1, wherein the magnetic field generator comprises a plurality of permanent magnets having known relative spatial positions and known relative orientations to each other. ### Claim 6 (depends on 1) The device of claim 1, wherein the magnetic field generator comprises a plurality of programmable magnets. ### Claim 7 (depends on 1) The device of claim 1, wherein the spatial vectors determined by the position analyzer correspond to spatial positions and orientations of fingers of the user where each magnetic flux sensor is located. ### Claim 8 (depends on 1) The device of claim 1, wherein the device comprises a glove. ### Claim 9 A device comprising: a magnetic field generator located at a predetermined position on the device, the magnetic field generator configured to generate a modulated magnetic field that is fixed in relation to the device; a plurality of magnetic flux sensors located at particular locations on the device, the particular locations on a body of a user of the device, each magnetic flux sensor configured to: (1) generate a demodulated signal based on detecting the modulated magnetic field at the particular location; (2) detect a strength and a direction of the demodulated signals and (3) generate an output signal based on the detected strength and the detected direction of the demodulated signals; one or more inertial measurement units (IMUs), each IMU being configured to generate a signal for an angular orientation of a particular magnetic flux sensor of the plurality of magnetic flux sensors, the particular magnetic flux sensor located on a particular location on the body of the user; and a position analyzer coupled to each of the plurality of sensors, the position analyzer configured to determine spatial vectors representing a position of each magnetic flux sensor relative to the magnetic field generator, wherein: the position of a magnetic flux sensor relative to the magnetic field generator is based on demodulating an output signal generated by the magnetic flux sensor, and the position analyzer is configured to determine further positional information for at least some of the plurality of magnetic flux sensors located on the particular location on the body of the user based on the signal generated by the one or more IMUs. ### Claim 10 (depends on 9) The device of claim 9, wherein the magnetic field generator comprises one or more electromagnets. ### Claim 11 (depends on 10) The device of claim 10, wherein each magnetic flux sensor includes a measurement circuit configured to extract a magnetic field having a certain frequency. ### Claim 12 (depends on 11) The device of claim 11, wherein different magnetic flux sensors include measurement circuits configured to extract magnetic fields having different frequencies. ### Claim 13 (depends on 9) The device of claim 9, wherein the magnetic field generator comprises a plurality of permanent magnets having known relative spatial positions and known relative orientations to each other. ### Claim 14 (depends on 9) The device of claim 9, wherein the magnetic field generator comprises a plurality of programmable magnets. ### Claim 15 (depends on 9) The device of claim 9, wherein the spatial vectors determined by the position analyzer correspond to spatial positions and orientations of the particular locations on the body of the user where each magnetic flux sensor is located. ### Claim 16 A method comprising: generating a modulated magnetic field that is fixed in relation to a device from a magnetic field generator located at a predetermined position on the device; detecting, by each of a plurality of magnetic flux sensors located at particular locations on the device that correspond to portions of a body of a user of the device located at a predetermined position relative to the device, the modulated magnetic field; generating, by each of the magnetic flux sensors located at particular locations on the device that correspond to portions of a body of a user of the device located at a predetermined position relative to the device, a demodulated signal based on the detected modulated field by each of the magnetic flux sensors; detecting, by each of the plurality of magnetic flux sensors, a strength and a direction of the demodulated signals; generating an output signal by each of the plurality of magnetic flux sensors based on the detected strength and the detected direction of the demodulated signals at each of the magnetic flux sensors; generating, by each of one or more inertial measurement units (IMUs), a signal for an angular orientation of a particular magnetic flux sensor of the plurality of magnetic flux sensors, the particular magnetic flux sensor located on a particular location on the body of the user; determining spatial vectors representing a position of each magnetic flux sensor relative to the magnetic field generator based on demodulating an output signal generated by the magnetic flux sensor; and determining further positional information for at least some of the plurality of magnetic flux Censor located on the particular locations on the body of the user based on the generated signal by the one or more IMUS. ### Claim 17 (depends on 16) The method of claim 16, wherein the magnetic field generator comprises one or more electromagnets. ### Claim 18 (depends on 17) The method of claim 17, wherein each magnetic flux sensor includes a measurement circuit configured to extract a magnetic field having a certain frequency. ### Claim 19 (depends on 18) The method of claim 18, wherein different magnetic flux sensors include measurement circuits configured to extract magnetic fields having different frequencies. ### Claim 20 (depends on 16) The method of claim 16, wherein the magnetic field generator comprises a plurality of programmable magnets.