# US 10,502,865 B2 · Sensing system and method for use in electromagnetic-absorbing material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,865 B2 - Document ID: US10502865B2 - Status: Granted - Kind: B2 - Application number: 16/420,601 - Filed: 2019-05-23 - Published: 2019-09-12 - Granted: 2019-12-10 - Earliest claimed: 2014-07-29 - Assignees: GroGuru, Inc. - Applicants: GroGuru, Inc. - Inventors: Jeffrey E. Campbell - Web page: https://patentgrep.com/patent/US10502865B2 ## CPC - G01W 1/02: Instruments for indicating weather conditions by measuring two or more variables, e.g. humidity, pressure, temperature, cloud cover or wind speed (G01W1/10 takes precedence) - H04Q 9/00: Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom - G05B 19/0421: {Multiprocessor system} - G08C 17/02: using a radio link - H04Q 2209/40: using a wireless architecture - G01W: METEOROLOGY (radar, sonar, lidar or analogous systems, designed for meteorological use G01S13/95, G01S15/88, G01S17/95) - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - G08C: TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS (fluid pressure transmitting systems F15B; mechanical means for transferring the output of a sensing member into a different variable G01D5/00; mechanical control systems G05G) ## Abstract Systems and methods for obtaining telemetry environmental readings from within an electromagnetic-absorbing material are disclosed herein. The system may include a self-contained power source powering a switch-mode amplifier to drive a multi-turn coil to be driven with a low-frequency carrier. ## Claims ### Claim 1 A telemetry system for obtaining environmental readings from within an electromagnetic-absorbing material, the system comprising: an environmental sensor having a sensor data output, wherein the environmental sensor comprises one or more of a moisture sensor, a temperature sensor, and a salinity sensor; a modulator having a data input coupled to the sensor data output and a signal output, wherein the modulator encodes data received at the data input onto a carrier produced at the signal output, and wherein the carrier has a carrier frequency between about 9 kHz and about 1705 kHz; a switch-mode amplifier coupled to the signal output and having an amplifier output; a multi-turn coil coupled to the amplifier output, wherein the multi-turn coil has a diameter of less than about 0.3 meter, and wherein the multi-turn coil has a reactance at the carrier frequency that forms a part of a frequency-dependent load network coupled to the amplifier; and a self-contained power source coupled to the switch-mode amplifier; a receiver coil positioned outside the material; and a data detector coupled to the receiver coil; and wherein the modulator, the amplifier, the multi-turn coil, and the self-contained power source are packaged within a water-tight enclosure and positioned inside the material. ### Claim 2 (depends on 1) The telemetry system of claim 1, wherein the carrier frequency is between about 50 kHz and about 490 kHz. ### Claim 3 (depends on 1) The telemetry system of claim 1, wherein the carrier frequency has a wavelength within the material, and the wavelength is much larger than the diameter of the multi-turn coil. ### Claim 4 (depends on 1) The telemetry system of claim 1, wherein the modulator comprises a digital processor configured to generate the carrier. ### Claim 5 (depends on 4) The telemetry system of claim 4, wherein the digital processor outputs the carrier as a substantially square wave, and wherein the amplifier converts the substantially square wave into a substantially sinusoidal wave. ### Claim 6 (depends on 1) The telemetry system of claim 1, wherein the modulator encodes the data received at the data input onto the carrier using on-off keying. ### Claim 7 (depends on 1) The telemetry system of claim 1, wherein the receiver coil is separated from the multi-turn coil by at least 2 meters. ### Claim 8 (depends on 7) The telemetry system of claim 7, wherein the multi-turn coil is positioned at least 0.3 meters from a surface of the material, and the receiver coil is positioned outside the material and at least 2 meters from the surface of the material. ### Claim 9 (depends on 1) The telemetry system of claim 1, wherein the material is one or more of: soil, water, rock, concrete, and combinations thereof. ### Claim 10 (depends on 1) The telemetry system of claim 1, wherein the material has a varying electromagnetic parameter selected from the group consisting of: permittivity, permeability, conductivity, and combinations thereof. ### Claim 11 (depends on 1) The telemetry system of claim 1, wherein the self-contained power source is one or more of: a battery, a fuel cell, a super capacitor. ### Claim 12 A method of telemetering from within an electromagnetic-absorbing material, the method comprising: sensing an environmental condition using an environmental sensor within the material to produce sensor data, wherein the sensor data comprises one or more of a moisture sensor, a temperature sensor, and a salinity sensor; encoding the sensor data onto a carrier using a modulator having a carrier frequency between about 9 kHz and about 1705 kHz; amplifying the carrier using a switch-mode amplifier to produce an amplified signal, wherein the switch-mode amplifier is powered from a self-contained power source; and coupling the amplified signal into a multi-turn coil, wherein the multi-turn coil has a diameter of less than about 0.3 meter, and wherein the multi-turn coil has a reactance at the carrier frequency that forms a part of a frequency-dependent load network coupled to the amplifier; positioning a receiver coil outside the material; and detecting the data using current induced in the receiver coil by mutual induction with the multi-turn coil; and positioning the modulator, the amplifier, the multi-turn coil, and the self-contained power source are packaged within a water-tight enclosure inside the material. ### Claim 13 (depends on 12) The method of claim 12, wherein the carrier frequency is between about 50 kHz and about 490 kHz. ### Claim 14 (depends on 12) The method of claim 12, wherein the carrier frequency has a wavelength within the material, and the wavelength is much larger than the diameter of the multi-turn coil. ### Claim 15 (depends on 12) The method of claim 12, wherein the encoding the sensor data onto a carrier comprises: generating a substantially square wave; modifying at least one parameter of the square wave, wherein the at least one parameter is selected from the group consisting of: duty cycle, phase, frequency, and combinations thereof; and wherein the amplifier converts the substantially square wave into a substantially sinusoidal wave. ### Claim 16 (depends on 12) The method of claim 12, wherein the encoding the sensor data onto a carrier further comprises: encoding the data using a serial asynchronous communications protocol having a predetermined baud rate. ### Claim 17 (depends on 16) The method of claim 16, wherein the baud rate is between about 500 and about 2000 baud per second. ### Claim 18 (depends on 12) The method of claim 12, further comprising: positioning the receiver coil at least 2 meters from a surface of the material, and wherein the multi-turn coil is positioned at least 0.3 meters from a surface of the material. ### Claim 19 (depends on 12) The method of claim 12, wherein an electric field produced by the multi-turn coil is less than a level of about 24000/F volts/meter when measured at a distance of 30 meters from the multi-turn coil, wherein F is the carrier frequency in kilohertz. ### Claim 20 (depends on 12) The method of claim 12, wherein an electric field produced by the multi-turn coil is less than a level of about 2400/F volts/meter when measured at a distance of 300 meters from the multi-turn coil, wherein F is the carrier frequency in kilohertz. ### Claim 21 (depends on 12) The method of claim 12, wherein the data is transmitted in a periodic burst, and the amplifier is turned off between bursts.