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Keyless entry system for automotive vehicle devices with weak-battery alarm

  • US 4,737,784 A
  • Filed: 09/18/1984
  • Issued: 04/12/1988
  • Est. Priority Date: 09/19/1983
  • Status: Expired due to Term
First Claim
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1. A keyless entry system for an automotive vehicle lock device for selectably actuating the lock device to either of a first locked position and a second unlocked position, comprising:

  • an electrical actuator associated with said lock device and responsive to a control signal to reverse the position of said lock device;

    a manual switch mounted on a vehicle body and manually operable;

    a transmitter responsive to a first radio signal which is produced in response to operation of said manual switch to output a second radio signal indicative of a predetermined digit of a unique code which identifies the transmitter;

    a battery mounted on said transmitter for supplying electric power to said transmitter;

    a controller mounted on said vehicle body and electrically connected to said manual switch to detect manual operation of said manual switch for transmitting said first radio signal in response to operation of said manual switch for activating said transmitter, receiving said second radio signal from said transmitter, comparing the unique code indicated by said second radio signal with a preset code, and in response to said manual switch, producing said control signal when said unique code matches said preset code; and

    a weak-battery alarm means for detecting when the voltage generated by said battery drops below a given voltage and producing an alarm in such cases, said weak-battery alarm means comprising a first means incorporated in said transmitter for monitoring supply voltage of said battery to produce a predetermined digit of a weak-battery indicative code to be contained in said second radio signal, and a second means incorporated in said controller and responsive to said weak-battery indicative code for producing said alarm.

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