US 5,686,887 A · Electronic locating device

Abstract

An apparatus and method suitable for use as an electronic remote locating device. The method including synchronizing an unprogrammed receiver with a transmitter so that the unprogrammed receiver responds only to the transmitter. The transmitter continuously increments a storage element when electrical power is initially applied to the transmitter and halts incrementing of the storage element when a first event is detected. Next, the transmitter saves the value of the storage element in memory as the unique identification code. The transmitter then transmits the identification code for a first predetermined length of time at a preselected frequency. The receiver monitors the preselected frequency searching for a received identification code for a predetermined period of time after electrical power is applied to the receiver. The receiver then verifies the validity of the received identification code and determines whether a prior identification code exists in the memory of the receiver. The receiver saves the received identification code in memory if the prior identification code was not found in the memory and halts the monitoring. The receiver then periodically monitors the preselected frequency range and compares the received identification code to the prior identification code. The receiver issues an indication to the user if the received identification code equals the prior identification code.

Claims44

Dependent claims

A method for assigning a unique identification code to a transmitter that transmits at least one of an old identification code and a new identification code within a single preselected frequency band, to a receiver that receives the identification codes within the single preselected frequency band, the method comprising the steps of:

continuously incrementing a value in a storage element after a first event is detected;
halting incrementing of the value in the storage element when a second event is detected, to generate a storage element value;
saving the storage element value in a memory of the transmitter as the new identification code;
transmitting the new identification code, the transmission continuing for a first predetermined period of time within the single preselected frequency band;
and
the old and new identification codes being transmitted and received within the single preselected frequency band at equal frequencies.

3 more elements

A method for synchronizing an unprogrammed receiver with a transmitter so that the unprogrammed receiver responds only to the transmitter, the transmitter transmitting at least one of an old and a new identification code within a single preselected frequency band, and the receiver receiving the identification codes within the single preselected frequency band, the method comprising the steps of:

continuously incrementing a value of a storage element in the transmitter when electrical power is initially applied to the transmitter;
halting incrementing of the value in the storage element in the transmitter when a first event is detected;
saving the value of the storage element in a memory of the transmitter as the new identification code;
transmitting the new identification code at a frequency defined by the single preselected frequency band, the transmission continuing for a first predetermined period of time;
monitoring the single preselected frequency band for a received identification code, the monitoring performed by the receiver during a portion of the first predetermined period of time and continuing for a second predetermined period of time beginning when electrical power is applied to the receiver, the old and new identification codes being transmitted and received within the single preselected frequency band at equal frequencies;
verifying the validity of the received identification code;
determining whether the received identification code exists in a memory of the receiver;
saving the received identification code in the memory of the receiver if the received identification code was not found in the memory of the receiver;
and
halting the monitoring of the single preselected frequency band for a third predetermined period of time.

7 more elements

Dependencies are inferred from the claim text.

Electronic locating device

Life of this patent

Electronic locating device

Life of this patent

Abstract

Claims44