×

Rolling code security system

  • US 8,233,625 B2
  • Filed: 07/22/2008
  • Issued: 07/31/2012
  • Est. Priority Date: 05/17/1995
  • Status: Expired due to Fees
First Claim
Patent Images

1. A wireless transmitter for sending an output signal to control an actuator to open or close a garage door, comprising:

  • a circuit board;

    a microprocessor on the circuit board;

    at least one button that, when actuated by an end user, initiates sending the output signal;

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

    an antenna;

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

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

    the antenna configured to transmit modulated radio frequency signals in response to the secured signal wherein the modulated radio frequency signals comprise any of three different signals,wherein a first of the different signals comprises a low amplitude radio frequency signal having a length of about 0.5 milliseconds followed by a high amplitude radio frequency signal having a length of about 1.5 milliseconds,wherein a second of the different signals is represented by a low amplitude radio frequency signal having a length of about 1.0 milliseconds followed by a high amplitude radio frequency signal having a length of about 1.0 milliseconds,wherein a third of the different signals is represented by a low amplitude radio frequency signal having a length of about 1.5 milliseconds followed by a high amplitude radio frequency signal having a length of about 0.5 milliseconds.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×