# US 10,502,676 B2 · Disposable witness corrosion sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,676 B2 - Document ID: US10502676B2 - Status: Granted - Kind: B2 - Application number: 15/639,441 - Filed: 2017-06-30 - Published: 2018-01-04 - Granted: 2019-12-10 - Earliest claimed: 2016-06-30 - Applicants: Seth S. Kessler; Christopher T. Dunn; Yosef Stein - Inventors: Seth S. Kessler; Christopher T. Dunn; Yosef Stein - Web page: https://patentgrep.com/patent/US10502676B2 ## CPC - G01N 17/04: Corrosion probes - G01N 17/02: Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement - G01N 27/04: by investigating resistance - H04W 84/18: Self-organising networks, e.g. ad-hoc networks or sensor networks - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Corrosion sensors are described. The corrosion sensors may include components formed from carbon nanotube structures and a corroding element formed of a material which corrodes more quickly than a target material being monitored by the corrosion sensor. The corroding material may be exposed to the environment to which the target material being monitored is exposed. The corrosion sensor may be passive, thus consuming little power. ## Claims ### Claim 1 A low power wireless sensor system for monitoring a state of corrosion of a target material, the low power wireless sensor system comprising: a witness corrosion sensor comprising a first resistive arm with a first resistance and a second resistive arm with a second resistance, the first resistive arm comprising a sensor element and at least one resistor comprising carbon nanotubes, wherein the sensor element is connected in parallel with the at least one resistor comprising carbon nanotubes, and the second resistive arm comprising at least one resistor comprising carbon nanotubes; processing circuitry configured to measure a difference between the first resistance and the second resistance and to determine a state of corrosion of the target material based on a difference between the first resistance and the second resistance; an energy storage module configured to store electrical energy and to provide power to at least a portion of the processing circuitry; and a wireless communication module coupled to the processing circuitry and configured to wirelessly communicate information external to the low power wireless sensor system. ### Claim 2 (depends on 1) The low power wireless sensor system of claim 1, wherein the state of corrosion is an amount of corrosion. ### Claim 3 (depends on 1) The low power wireless sensor system of claim 1, wherein the sensor element has a variable resistance configured to vary based at least in part on a state of corrosion of the sensor element. ### Claim 4 (depends on 3) The low power wireless sensor system of claim 3, wherein the sensor element is configured to be disposed within a same environment as the target material, wherein at least a portion of the second resistive arm is configured to not to be disposed within the same environment. ### Claim 5 (depends on 4) The low power wireless sensor system of claim 4, wherein the sensor element is configured to corrode faster than the target material. ### Claim 6 (depends on 1) The low power wireless sensor system of claim 1, wherein the at least one resistor in the second resistive arm is covered by a non-corroding material. ### Claim 7 (depends on 1) The low power wireless sensor system of claim 1, wherein the information comprises the state of corrosion of the target material. ### Claim 8 A wireless sensor system for monitoring a state of corrosion of a target material, the wireless sensor system comprising: a passive sensor apparatus comprising a first resistive arm with a first resistance and a second resistive arm with a second resistance, the first resistive arm comprising a sensor element and at least one resistor comprising carbon nanotubes, wherein the sensor element is connected in parallel with the at least one resistor comprising carbon nanotubes, and the second resistive arm comprising at least one resistor comprising carbon nanotubes; a circuit configured to measure a difference between the first resistance and the second resistance; a processor configured to determine a state of corrosion of the target material based on a difference between the first resistance and the second resistance measured by the circuit; an energy storage module configured to store electrical energy and to provide power to at least a portion of the circuit; and transmit circuitry coupled to the circuit and configured to transmit corrosion information. ### Claim 9 (depends on 8) The wireless sensor system of claim 8, wherein the sensor element is configured to corrode faster than the target material. ### Claim 10 (depends on 8) The wireless sensor system of claim 8, wherein the processor is further configured to estimate a remaining useful life of the target material based at least in part on a corrosion rate of the target material. ### Claim 11 (depends on 8) The wireless sensor system of claim 8, wherein the circuit comprises carbon nanotubes. ### Claim 12 (depends on 8) The wireless sensor system of claim 8, wherein the transmit circuitry is a wireless communication module coupled to the circuit and configured to wirelessly communicate the state of corrosion of the target material. ### Claim 13 (depends on 8) The wireless sensor system of claim 8, wherein the energy storage module comprises an energy harvester. ### Claim 14 A method for operating a low power wireless sensor system comprising: measuring, with processing circuitry disposed in the low power wireless sensor system, a difference between a resistance of a first resistive arm and a resistance of a second resistive arm of a witness corrosion sensor comprising the first resistive arm and the second resistive arm, the first resistive arm comprising a sensor element and at least one resistor comprising carbon nanotubes, wherein the sensor element is connected in parallel with the at least one resistor comprising carbon nanotubes, and the second resistive arm comprising at least one resistor comprising carbon nanotubes; determining, with the processing circuitry, a state of a target material based at least in part on the measured difference; providing, with an energy storage module configured to store electrical energy, power to at least a portion of the processing circuitry; and wirelessly communicating, with a wireless communication module, information external to the low power wireless sensor system. ### Claim 15 (depends on 14) The method of claim 14, further comprising exposing the sensor element and the target material to a same environment. ### Claim 16 (depends on 14) The method of claim 14, wherein the sensor element has a variable resistance configured to vary in dependence on a state of corrosion of the sensor element. ### Claim 17 (depends on 14) The method of claim 14, wherein the determining comprises estimating a remaining useful life of the target material based at least in part on a corrosion rate of the target material. ### Claim 18 (depends on 14) The method of claim 14, wherein the sensor element is configured to corrode faster than the target material. ### Claim 19 (depends on 14) The method of claim 14, further comprising: storing energy in the energy storage module with an energy harvester. ### Claim 20 (depends on 14) The method of claim 14, wherein the wirelessly communicating comprises wirelessly transmitting signals representing the measured difference from the processing circuitry to a processor external to the low power wireless sensor system.