# US 2014/0191843 A1 · Machine security system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191843 A1 - Document ID: US20140191843A1 - Status: Published application - Kind: A1 - Application number: 13/734,112 - Filed: 2013-01-04 - Published: 2014-07-10 - Earliest claimed: 2013-01-04 - Assignees: Caterpillar Inc. - Applicants: Caterpillar Inc - Inventors: Mark T. DeCou; Paul D. Smith; Anton D. Volkov - Web page: https://patentgrep.com/patent/US20140191843A1 ## CPC - G07C 9/00309: {operated with bidirectional data transmission between data carrier and locks} - B60R 25/24: using electronic identifiers containing a code not memorised by the user - G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR ## Abstract A machine security system for authenticating a machine key is disclosed. The machine security system comprises a microcontroller for detecting insertion of a machine key in a key slot of the machine. The machine key comprises of an embedded transponder. Based on detection of the machine key in the key slot, the microcontroller transmits an interrogation signal for charging the transponder. The microcontroller then receives a response signal from the transponder. The transponder sends the response signal when substantially charged by the interrogation signal. The response signal is encoded with an authentication code for authenticating the machine key. The microcontroller decodes the authentication code from the received response signal and authenticates the machine key based on the decoded authentication code. ## Claims ### Claim 1 A machine security system comprising: a microcontroller configured to: detect insertion of a machine key in a key slot of a machine, wherein the machine key comprises an embedded transponder; transmit, responsive to the detection, an interrogation signal to the transponder; receive, from the transponder, a response signal, wherein the response signal is received when the transponder is substantially charged by the interrogation signal, and wherein the response signal comprises an authentication code for authenticating the machine key; decode the authentication code from the response signal; and authenticate the machine key based on the decoded authentication code. ### Claim 2 (depends on 1) The machine security system of claim 1, wherein the microcontroller is electrically coupled to an antenna coil through a filtering and amplification unit for communicating with the transponder. ### Claim 3 (depends on 2) The machine security system of claim 2, wherein the filtering and amplification unit comprises a filtering circuit configured to filter one or more noise signals from the response signal, or the interrogation signal, or both. ### Claim 4 (depends on 2) The machine security system of claim 2, wherein the filtering and amplification unit further comprises an amplification circuit configured to amplify the response signal, or the interrogation signal, or both. ### Claim 5 (depends on 1) The machine security system of claim 1, wherein the authentication code is decoded from the response signal using at least one of a pulse width measurement, a pulse time period measurement and a cycle count measurement. ### Claim 6 (depends on 1) The machine security system of claim 1, wherein an integrated circuit chip is configured to filter one or more noise signals from the response signal. ### Claim 7 (depends on 1) The machine security system of claim 1, wherein an integrated circuit chip is configured to amplify the response signal. ### Claim 8 (depends on 1) The machine security system of claim 1, wherein at least one of the interrogation signal and the response signal is a radio frequency signal. ### Claim 9 (depends on 1) The machine security system of claim 1, wherein the response signal is modulated with the authentication code using a frequency shift keying modulation. ### Claim 10 (depends on 1) The machine security system of claim 1, wherein the microcontroller is further configured to authenticate the machine key based on matching of the decoded authentication code with one of a plurality of preset authentication codes. ### Claim 11 (depends on 1) The machine security system of claim 1, wherein the microcontroller is further configured to transmit a control signal to a machine control unit based on a success or a failure of the authentication of the machine key. ### Claim 12 (depends on 11) The machine security system of claim 11, wherein the control signal is one of a lock signal, an unlock signal, an ignition on signal, and an ignition off signal. ### Claim 13 A method comprising: detecting, by a microcontroller, insertion of a machine key in a key slot of a machine, wherein the machine key comprises of an embedded transponder; transmitting, by the microcontroller, an interrogation signal for charging the transponder; receiving, by the microcontroller, a response signal, wherein the response signal comprises an authentication code for authenticating the machine key; decoding, by the microcontroller, the authentication code; and authenticating, by the microcontroller, the machine key based on the decoded authentication code. ### Claim 14 (depends on 13) The method of claim 13, wherein the microcontroller is electrically coupled to an antenna coil through a filtering and amplification unit for communicating with the transponder. ### Claim 15 (depends on 13) The method of claim 13, further comprising filtering one or more noise signals from the response signal, or the interrogation signal, or both. ### Claim 16 (depends on 13) The method of claim 13, further comprising amplifying the response signal, or the interrogation signal, or both. ### Claim 17 (depends on 13) The method of claim 13, wherein the authentication code is decoded from the response signal using at least one of a pulse width measurement, a pulse time period measurement and a cycle count measurement. ### Claim 18 (depends on 13) The method of claim 13, further comprising transmitting, by the microcontroller, a control signal to a machine control unit based on a success or a failure of the authentication of the machine key. ### Claim 19 (depends on 18) The method of claim 18, wherein the control signal is one of a lock signal, an unlock signal, an ignition on signal, and an ignition off signal. ### Claim 20 A system comprising: a microcontroller configured to: detect insertion of a machine key in a key slot of a machine, wherein the machine key comprises of an embedded transponder; generate an interrogation signal, wherein the interrogation signal comprises a digital signal approximation of a sinusoidal or another periodic waveform; transmit the interrogation signal; receive a response signal comprising a plurality of pulses, wherein the plurality of pulses represent an authentication code for authenticating the machine key, and wherein the response signal is a radio frequency signal; measure at least one of a pulse width, a pulse time period, and a cycle count for each of the plurality of pulses; and determine the authentication code by assigning logic levels to each of the plurality of pulses based on the measuring.