Remote controlled garage door opening system

• US 20040085185A1
• Filed: 10/24/2003
• Published: 05/06/2004
• Est. Priority Date: 09/06/1996
• Status: Abandoned Application

• Current Assignee: Microchip Technology Incorporated, Overhead Door Corporation (Sanwa Holdings Corp.)
• Original Assignee: Microchip Technology Incorporated, Overhead Door Corporation (Sanwa Holdings Corp.)
• Inventors: Bruwer, Frederick J., Marneweck, Willem J., Waggamon, Dennis W., Delport, Vivien N.
• Application Number:
  US10/693,748
• Publication Number:
  US 20040085185A1
• Time in Patent Office: Days
• US Class Current: 340/5.7
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: G08C 19/28 using pulse code
• CPC Class Codes: G08C 2201/62 Rolling code
• CPC Class Codes: H04J 13/0074 Code shifting or hopping
• CPC Class Codes: Y10T 70/5973 Remote control

Abstract

A remote control system for opening and closing a barrier, such as a garage door, includes an RF receiver and a plurality of RF transmitters. The transmitters and receiver include circuitry programmed to provide transmission of encrypted code signals each time the transmitters are used and employing a code hopping method which prevents unauthorized signal interception or code “grabbing”. The system is operated in a code learning mode for the receiver by momentarily actuating a receiver learn mode button for receiving each transmitter identification code and a secret decryption key for that transmitter with the system automatically returning to the operate mode. Each transmitter identification and secret key code signal is automatically and randomly stored in an available and unused memory in the receiver circuitry. A multibit hopping code is transmitted from each transmitter to the receiver with each transmitter operation in the operate mode of the system and the hopping code changes with each transmission to prevent theft or code grabbing and resultant unauthorized operation of the system.

Claims

1. A remote controlled garage door opening and closing system, comprising:

a mechanism operably connected to a garage door to open or close said door in response to a command signal;

a plurality of transmitters operably generating respective changeable hopping code signals, each hopping code signal comprising an encrypted first synchronization value;

a receiver for intercepting said changeable hopping code signals;

first means within said receiver for operably generating unique multibit secret keys respectively identifiably associated with said plurality of transmitters; and

second means within said receiver (i) for performing a non-linear decoding function on an intercepted changeable hopping code signal using one of said multibit secret keys, thereby to generate a second synchronization value (ii) for comparing said second synchronization value with said first synchronization value and generating said command signal when said second synchronization value bears a predetermined matching relationship with said first synchronization value (iii) in the absence of said predetermined matching relationship, for performing another nonlinear decoding function on said intercepted signal using a different one of said multibit secret keys to generate another second synchronization value, and (iv) for continually repeating the sequence until a second synchronization value is found which bears the said predetermined matching relationship with said first synchronization value.

2. The system as recited in claim 1, wherein said first synchronization value increments every time its associated transmitter is activated.

3. The system as defined by claim 1, wherein said plurality of transmitters have associated therewith multibit secret keys respectively corresponding to, but being separate from, the multibit secret keys associated with the receiver.

4. A remote controlled garage door opening and closing system, comprising:

a mechanism operably connected to a garage door to open or close said door in response to a command signal;

a plurality of transmitters operably generating respective changeable hopping code signals, each hopping code signal comprising an encrypted first synchronization value;

a receiver for intercepting said changeable hopping code signals;

first means within said receiver for operably generating unique multibit secret keys respectively identifiably associated with said plurality of transmitters;

second means within said receiver (i) for performing a non-linear decoding function on an intercepted changeable hopping code signal using one of said multibit secret keys, thereby to generate a second synchronization value (ii) for comparing said second synchronization value with said first synchronization value and generating said command signal when said second synchronization value bears a predetermined matching relationship with said first synchronization value (iii) in the absence of said predetermined matching relationship, for performing another non-linear decoding function on said intercepted signal using a different one of said multibit secret keys to generate another second synchronization value, and (iv) for continually repeating the sequence until a second synchronization value is found which bears the said predetermined matching relationship with said first synchronization value;

a microprocessor associated with said receiver; and

third means for controlling the mode of operation of said microprocessor between a learn mode an operate mode, said third means being operable to place said microprocessor in a learn mode for a predetermined length of time and automatically returning said microprocessor to the operate mode at the end of said time.

5. A remote controlled garage door opening and closing system, comprising:

a mechanism operably connected to a garage door to open or close said door in response to a command signal;

a plurality of transmitters operably generating respective changeable hopping code signals, each hopping code signal comprising an encrypted first synchronization value;

a receiver for intercepting said changeable hopping code signals;

first means within said receiver for operably generating unique multibit secret keys respectively identifiably associated with said plurality of transmitters;

second means within said receiver (i) for performing a non-linear decoding function on an intercepted changeable hopping code signal using one of said multibit secret keys, thereby to generate a second synchronization value (ii) for comparing said second synchronization value with said first synchronization value and generating said command signal when said second synchronization value bears a predetermined matching relationship with said first synchronization value (iii) in the absence of said predetermined matching relationship, for performing another nonlinear decoding function on said intercepted signal using a different one of said multibit secret keys to generate another second synchronization value, and (iv) for continually repeating the sequence until a second synchronization value is found which bears the said predetermined matching relationship with said first synchronization value;

memory means within said receiver; and

third means within said receiver for automatically and randomly storing said multibit secret keys in said memory means without user intervention.