Paired lost item finding system

• US 6,366,202 B1
• Filed: 09/01/2000
• Issued: 04/02/2002
• Est. Priority Date: 09/07/1999
• Status: Active Grant

• Current Assignee: Lawrence D. Rosenthal
• Original Assignee: Lawrence D. Rosenthal
• Inventors: Rosenthal, Lawrence D.
• Primary Examiner(s): POPE, DARYL C
• Application Number:
  US09/653,388
• Time in Patent Office: 578 Days
• Field of Search: 340/573.2, 340/686.6, 340/539, 340/331, 340/329, 340/311.1, 345/98, 455/575
• US Class Current: 340/539.32
• CPC Class Codes: G08B 21/0222 Message structure or message content, e.g. message protocol
• CPC Class Codes: G08B 21/0227 System arrangements with a plurality of child units
• 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
• CPC Class Codes: G08B 21/0263 System arrangements wherein the object is to detect the direction in which child or item is located
• CPC Class Codes: G08B 21/0288 Attachment of child unit to child/article
• CPC Class Codes: G08B 21/24 Reminder alarms, e.g. anti-loss alarms

Abstract

A lost item finding system including at least two nearly identical locators. Either one can be used to find the other and whatever items are attached to it. In the preferred embodiment, acoustic signals near 6500 Hz are used to broadcast a search signal from an available locator to a lost one. Preferably, the search signal includes a sequences of tones having predetermined frequency differences between them. The lost locator is usually in a sleep mode, in which it nonetheless is capable of recognizing the beginning of the search signal. The locator turns on to an active mode in which it consumes more power. It determines the baseline frequency and then identifies whether the signal it is receiving conforms to the predetermined frequency differences between the sequence of tones. If it does, the lost locator transmits a beacon signal that can be perceived by the user as he searches for the lost item. The beacon signal may include both an audible signal and a flashing light emitting diode. Another feature allows the number of false alarms to be reduced, particularly in a noisy environment, but also allows the locators to be operable in a noisy environment. Yet further capabilities include the selection of baseline frequencies or the temporary deactivation of additionally available locators. Advantageously, both the transmission and reception of the audio signal is accomplished with one piezoelectric transducer, and the efficiency of the transducer is increased by forming a resonant cavity having a cap both protecting the piezoelectric transducer and forming a side emitting annular port.

Claims

1. A paired finding system comprising at least two locators, any of said locators being usable to find any other of said locators, each locator comprising:

signal receiving means for receiving and identifying a search signal emitted from another of said locators;

beacon signaling means for emitting at least one beacon signal to which a human user is sensitive in response to said receiving means identifying said search signal;

search signaling means for emitting said search signal upon activation by said user;

a case accommodating said beacon and search signaling means, said signal receiving means and an activatable button accessible by said user from an exterior of said case; and

a processor accommodated in said case, monitoring said signal receiving means and an activation of said button while in a first mode in which said processor consumes a first amount of current, and controlling said signal receiving means, said beacon signal means, and said search signal means while in a second mode in which said processor consumes a second amount of current substantially larger than said first amount.

2. The system of claim 1, wherein said second amount is more than 100 times said first amount.

3. The system of claim 1, wherein said search signaling means emits an RF signal.

4. The system of claim 3, wherein said beacon signaling means emits a visual signal.

5. The system of claim 1, further comprising deactivation means for deactivating said beacon signaling means for a predetermined period of time.

6. The system of claim 1, wherein each locator includes a programmable code and wherein said search signal is encoded according to said code and wherein said signal means identifies said search signal according to said code.

7. A paired finding system comprising at least two locators, any of said locators being usable to find any other of said locators, each locator comprising:

signal receiving means for receiving and identifying a search signal emitted from another of said locators;

beacon signaling means for emitting at least one beacon signal to which a human user is sensitive in response to said receiving means identifying said search signal;

search signaling means for emitting said search signal upon activation by said user; and

a case accommodating said beacon and search signaling means and said signal receiving means and an activatable button accessible by said user from an exterior of said case;

wherein said search signaling means requires a plurality of activations of said button to emit said search signal.

8. An audio finding system, comprising at least two locators, any of said locators being usable to find any other of said locators, each locator comprising:

an audio transducer;

control circuitry for receiving a first search signal through said audio transducer from another of said locators, for transmitting a second search signal to another of said locators through said audio transducer, and in response to reception of said first search signal for transmitting a beacon signal through said audio transducer that is audible to a user;

a case accommodating said transducer and said piezoelectric transducer and including a circularly symmetric acoustic cavity, wherein said piezoelectric transducer is disposed on one end of said cavity; and

a substantially circular cap covering the other end of said circularly symmetric cavity and spaced apart from said case by an annular port extending outwardly from a central axis of said acoustic cavity and communicating said acoustic cavity to an outside of said case, wherein said annular port extends radially outward from said central axis.

9. A paired finding system comprising at least two locators, any of said locators being usable to find any other of said locators, each locator comprising:

an RF receiver receiving and identifying an RF search signal emitted from another of said locators;

an RF search transmitter for emitting said RF search signal;

a beacon transmitter for emitting at least one of an audio and optical beacon signal in response to said identified search signal and detectable by a human user; and

a button in said transmitter effective by multiple activations of said button by said user to initiate said emitting of said RF search signal.

10. The system of claim 9, wherein said beacon signal is an audio signal.

11. A method of using either of two locators to locate the other of said two locators, comprising the steps of:

transmitting from either locator a search signal;

receiving at said other locator said search signal and identifying it as being emitted from said other locator;

in response to said identifying, emitting form said other locator a beacon signal to which a human is sensitive; and

in response to said beacon signal, said human retrieving said other locator.

12. The method of claim 11, wherein said search signal is an acoustic signal.

13. The method of claim 12, wherein said beacon signal is another acoustic signal.

14. The method of claim 11, wherein said search signal is an RF signal.

15. A method of using either of two locators to locate the other of said two locators, comprising the steps of:

transmitting from either locator a search signal including a search signal period and a subsequent quiet period;

receiving at said other locator said search signal and identifying both of said search signal period and said quiet period; and

in response to said identifying, emitting form said other locator a beacon signal to which a human is sensitive.

16. The method of claim 15, wherein said search signal is an audio signal.

17. The method of claim 16, wherein said two search signal period includes a first search signal sub-period differing by a predetermined frequency difference from a subsequent second search signal sub-period.

18. The method of claim 15, wherein said beacon signal is another audio signal.