Portable loss-protection device

• US 5,801,627 A
• Filed: 03/27/1995
• Issued: 09/01/1998
• Est. Priority Date: 03/27/1995
• Status: Expired due to Fees

• Current Assignee: Dudley B. Hartung
• Original Assignee: Dudley B. Hartung
• Inventors: Hartung, Dudley B.
• Primary Examiner(s): MULLEN, THOMAS J
• Application Number:
  US08/411,440
• Time in Patent Office: 1,254 Days
• Field of Search: 340/568, 340/571, 340/572, 340/573, 340/539
• US Class Current: 340/568.1
• CPC Class Codes: G08B 13/1427 with transmitter-receiver for distance detection
• CPC Class Codes: G08B 21/0216 Alarm cancellation after generation
• CPC Class Codes: G08B 21/023 Power management, e.g. system sleep and wake up provisions
• CPC Class Codes: G08B 21/0247 System arrangements wherein the alarm criteria uses signal strength

Abstract

An electronic device consisting of a Transmit Unit 11 and a Receiver-Alarm Unit 60 for the protection of portable electronic or other equipment from theft or inadvertent loss. The Transmit Unit 11 transmits a signal which is turned on or off according to the state of On-Select Switches 14 and Off-Select Switches 16. After a predetermined time from Pulse-Counter Timer 12 the signal may also be turned off. The Receiver-Alarm Unit 60 receives with Receiver 62 the transmission. Decoder 64 determines if the signal is being turned on or off. If it is turned on the Threshold Detector 66 monitors the incoming signal and when it falls below a threshold causes an alarm to be given.

Claims

1. A system with two units, the first for generating distance determining signals and the second for receiving these signals and determining that the two units are separated by a certain distance and then causing an action command signal where said distance determining signals are activated and deactivated according to predetermined criteria, the system including:

said first and second units;

a transmitter in said first unit to transmit a distance determining signal;

switching means in said first unit to turn on and turn off said distance determining signal;

encoding means in said first unit to send a coded message at the beginning and another coded message at the end of said distance determining signal;

a receiver in said second unit to receive transmissions from the first unit;

a decoder in said second unit to recognize the coded messages at the beginning and end of said transmission;

signal strength determination means in said second unit to ascertain when received transmission strength is below a predetermined level; and

a controller in said second unit to trigger the action command signal when the decoder has recognized a coded beginning message and has not yet recognized a coded ending message and the signal strength determination is below the predetermined level.

2. A system as shown in claim 1 where the coded messages for beginning and ending messages include a particular device identification code.

3. A system as shown in claim 1 where beginning and ending messages are identical.

4. A system as shown in claim 1 where the beginning and ending messages are different.

5. A system as shown in claim 1 where predetermined criteria for activation or deactivation of the distance determination signal includes signals from sensors and switches.

6. A system as shown in claim 1 where predetermined criteria for activation of the distance determination signal includes electrical inputs from a device to which the first unit is attached.

7. A system as shown in claim 1 where a time measurer deactivates the distance determination signal at a predetermined time after a predetermined change-of-state, including start-up and shut-down, of a device to which the first unit is attached.

8. A system with two units, the first for generating distance determining signals and the second for receiving these signals and causing an action command signal when the units are separated by a predetermined distance, where the distance determining signals are activated and deactivated according to predetermined criteria, the system consisting of:

switching means in the first unit to turn on and turn off the generated distance determining signals;

a receiver in the second unit to receive transmissions from the first unit;

a distance determinator in the second unit to ascertain when the two units are over a certain distance apart; and

a controller in the second unit to trigger an action signal when the distance determinator indicates the units are over a certain distance apart.

9. A system with two units which can communicate between each other so that one unit can determine a distance between itself and another unit and cause action command signals in accordance to the determined distance, with the communicating signals activated and deactivated according to predetermined criteria, the system consisting of:

first and second units;

a transmitter in the first unit and a receiver in the second unit to transmit and receive signals;

a switch in said first unit to turn on and turn off transmit signals in accordance to predetermined criteria;

a detector in said second unit to detect communicating signals;

a distance determinator in said second unit to ascertain when the two units are a certain distance apart; and

a controller in said second unit to trigger action signals when the distance determinator indicates the units are a certain distance apart.