Rolling code security system

• US 8,284,021 B2
• Filed: 07/22/2008
• Issued: 10/09/2012
• Est. Priority Date: 05/17/1995
• Status: Expired due to Fees

• Current Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Original Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Inventors: Farris, Bradford L., Fitzgibbon, James J.
• Primary Examiner(s): Brown, Vernal U
• Application Number:
  US12/177,366
• Publication Number:
  US 20080297370A1
• Time in Patent Office: 1,540 Days
• Field of Search: 340/5.71, 340/5.64, 340/5.61, 340/825.72, 340/3.1, 340/5.28, 340/4.11, 340/4.61, 380/239, 380/262
• US Class Current: 340/5.71
• CPC Class Codes: G07C 2009/00214 by one push button
• CPC Class Codes: G07C 2009/00253 dynamically, e.g. variable code - rolling code
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 2209/84 Vehicles
• CPC Class Codes: H04L 9/32 including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials
• CPC Class Codes: H04W 12/02 Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII]
• CPC Class Codes: H04W 12/033 of the user plane, e.g. user's traffic
• CPC Class Codes: H04W 12/80 Arrangements enabling lawful interception [LI]
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

A rolling code transmitter is useful in a security system for providing secure encrypted RF transmission comprising an interleaved trinary bit fixed code and rolling code. A receiver demodulates the encrypted RF transmission and recovers the fixed code and rolling code. Upon comparison of the fixed and rolling codes with stored codes and determining that the signal has emanated from an authorized transmitter, a signal is generated to actuate an electric motor to open or close a movable barrier.

Claims

1. A wireless transmitter for sending a radio frequency signal to a wireless receiver to actuate an electric motor to open or close a movable barrier, comprising:

a circuit;

a microprocessor coupled to the circuit;

at least one switch configured to be actuated to effect transmitting the radio frequency signal;

at least one light emitting diode coupled to the circuit;

an antenna;

the microprocessor configured to use a changing value that varies with actuation of the transmitter;

the microprocessor configured to output a command in response to the changing value and a fixed value such that the command varies with actuations of the transmitter; and

the antenna configured to transmit the radio frequency signal that comprises the command wherein the radio frequency signal comprises any of three different values,

wherein each of the different values comprises a series of four portions, each of the four portions having a length of about 0.5 milliseconds, wherein a first portion comprises a low amplitude radio frequency signal, a second portion comprises one of a low amplitude radio frequency signal and a high amplitude radio frequency signal, a third portion comprises one of a low amplitude radio frequency signal and a high amplitude radio frequency signal, and a fourth portion comprises a high amplitude radio frequency signal.

2. The wireless transmitter of claim 1 wherein the at least one light emitting diode is responsive to at least one of the at least one switch and configured to indicate that at least one of the at least one switch has been actuated.

3. The wireless transmitter of claim 1 wherein the changing value varies with each actuation of the transmitter.

4. The wireless transmitter of claim 1 wherein the changing value is considered valid and allowed to vary within a predetermined range of values.

5. The wireless transmitter of claim 1 wherein the radio frequency signal comprises a plurality of radio frequency signals.

6. The wireless transmitter of claim 1 further comprising an oscillator configured to receive the command and to send the command, via the antenna.

7. The wireless transmitter of claim 1 wherein the microprocessor is configured to combine a trinary version of the changing value with a trinary value responsive to the fixed value, wherein microprocessor combines the trinary version of the rolling value with the trinary value responsive to the fixed value by interleaving trinary bits for the trinary version of the rolling value with trinary bits for the trinary value responsive to the fixed value to thereby provide the command in the form of an interleaved trinary combined result.

8. The wireless transmitter of claim 1 wherein the microprocessor is configured to combine a binary-coded trinary code version of the changing value with a binary-coded trinary code version of the fixed value.

9. The wireless transmitter of claim 1 wherein the circuit is disposed on a circuit board.

10. The wireless transmitter of claim 1 wherein the circuit is disposed within a housing.

11. A wireless transmitter for sending a radio frequency signal to a wireless receiver to actuate an electric motor to open or close a movable barrier, comprising:

a circuit;

a microprocessor coupled to the circuit;

at least one switch configured to be actuated to effect transmitting the radio frequency signal;

at least one light emitting diode coupled to the circuit;

an antenna;

the antenna configured to receive from the circuit a command responsive to a changing value and a fixed value such that the command varies with actuation of the wireless transmitter;

the antenna configured to transmit the radio frequency signal that comprises the command wherein the radio frequency signal comprises any of three different values,

wherein each of the different values comprises a series of four portions, each of the four portions having a length of about 0.5 milliseconds, wherein a first portion comprises a low amplitude radio frequency signal, a second portion comprises one of a low amplitude radio frequency signal and a high amplitude radio frequency signal, a third portion comprises one of a low amplitude radio frequency signal and a high amplitude radio frequency signal, and a fourth portion comprises a high amplitude radio frequency signal.

12. A wireless transmitter for sending a radio frequency signal to a garage door operator having a wireless receiver such that when the garage door operator receives the radio frequency signal, the garage door operator actuates an electric motor to open or close a movable barrier such as a garage door, wherein the garage door operator actuates the electric motor in response to receiving a control message comprising two consecutive series of twenty three-valued elements separated by a sink bit, the control message conveyed by the radio frequency signal wherein the radio frequency signal comprises a series of high amplitude portions and low amplitude portions wherein the high amplitude portions and the low amplitude portions have lengths of at least one of a group comprising about 0.5 milliseconds, about 1.0 milliseconds, and about 1.5 milliseconds, the wireless transmitter comprising:

a circuit;

a microprocessor coupled to the circuit;

at least one switch configured to be actuated to effect transmitting the radio frequency signal;

at least one light emitting diode responsive to the at least one switch;

an antenna in combination with the microprocessor configured to send the radio frequency signal conveying the control message.

13. The wireless transmitter of claim 12 wherein the microprocessor is configured to provide a changing value that varies with actuation of the transmitter.

14. The wireless transmitter of claim 13 wherein the microprocessor is configured to output the control message in response to the changing value and a fixed value such that the control message varies with actuations of the transmitter.

15. The wireless transmitter of claim 12 wherein the radio frequency signal conveys the control message via a series of three different values;

wherein a first of the different values is represented by a first amplitude radio frequency signal having a length of about 0.5 milliseconds followed by a second amplitude radio frequency signal having a length of about 1.5 milliseconds,

wherein a second of the different values is represented by a first amplitude radio frequency signal having a length of about 1.0 milliseconds followed by a second amplitude radio frequency signal having a length of about 1.0 milliseconds,

wherein a third of the different values is represented by a first amplitude radio frequency signal having a length of about 1.5 milliseconds followed by a second amplitude radio frequency signal having a length of about 0.5 milliseconds.