Electronic tether for portable objects

1. An electronic tether comprising:

a monitoring module associated with a monitored object, wherein the monitoring module comprises an RFID tag configured for receiving a polling signal and for transmitting a reflected signal in response to the polling signal, wherein the reflected signal comprises an RFID tag identifier unique to the RFID tag; and

an alert module comprising:

a memory comprising the RFID tag identifier;

an RFID tag polling manager comprising instructions for sending the polling signal;

a receiver configured for receiving the reflected signal from the RFID tag;

a separation manager comprising instructions for:

determining whether the reflected signal comprising the RFID tag identifier has been received;

issuing an “object-not-present” signal if the reflected signal comprising the RFID tag has not been received;

in response to the object-not-present signal, identifying the RFID tag as non-responsive;

resending the polling signal; and

if the RFID tag identifier is not received after at least one resend attempt, then issuing an object-not-present alert with respect to the non-responsive RFID tag.

2. The electronic tether of claim 1 , wherein the object-not-present alert is an audible alarm.

3. The electronic tether of claim 2 , wherein the audible alarm is a synthesized voice.

4. The electronic tether of claim 1 , wherein the object-not-present alert is a visual alarm.

5. The electronic tether of claim 4 , wherein the visual alarm is a text message.

6. The electronic tether of claim 1 , wherein the object-not-present alert identifies the monitored object that is associated with the monitoring module.

7. The electronic tether of claim 1 , wherein the alert module further comprises instructions for:

accepting an object-not-present alert cancel request from a user;

determining whether a reflected signal comprising the RFID tag identifier has been received; and

issuing an object return alert if the reflected signal comprising the RFID tag identifier has been received.

8. The electronic tether of claim 1 , wherein the alert module is incorporated into a portable device.

9. The electronic tether of claim 8 , wherein the portable device is selected from the group consisting of a cellular telephone, a PDA, a laptop computer, a portable music player, and a wristwatch.

10. The electronic tether of claim 1 , wherein the polling manager comprises means for varying the polling signal signal strength, and wherein the alert module further comprises instructions for establishing a preset separation distance between the alert module and the monitoring module by adjusting the polling signal signal strength.

11. The electronic tether of claim 1 , wherein the receiver comprises means for varying the receiver sensitivity to the reflected signal, and wherein the alert module further comprises instructions for establishing a preset separation distance between the alert module and the monitoring module by adjusting the receiver sensitivity.

12. The electronic tether of claim 1 , wherein a preset separation distance between the alert module and the monitoring module is established by selection of the RFID tag based on a measure of signal strength of the reflected signal.

13. The electronic tether of claim 1 , wherein the RFID tag is selected from the group consisting of a passive RFID tag, a semi-passive RFID tag, and an active RFID tag.

14. The electronic tether of claim 1 , wherein the alert module further comprises instructions for:

prior to resending the polling signal, increasing the polling signal signal strength by a preset increment;

resending the polling signal; and

if the RFID tag identifier is not received after the polling signal signal strength reaches a maximum signal strength level, then issuing the object-not-present alert with respect to the non-responsive RFID tag.

15. The electronic tether of claim 1 , wherein the alert module further comprises instructions for:

prior to resending the polling signal, increasing the receiver sensitivity by a preset increment;

resending the polling signal to the non-responsive RFID tag; and

if the RFID tag identifier associated with the object is not received after the receiver sensitivity reaches a maximum sensitivity, then issuing the object-not-present alert with respect to the non-responsive RFID tag.

16. A method for monitoring an object using an alert module comprising:

associating an RFID tag identifier with an object and storing the RFID tag identifier in the alert module;

sending a polling signal from the alert module module;

receiving a polling signal at a monitoring module associated with a monitored object, wherein the monitoring module comprises an RFID tag;

transmitting a reflected signal from the RFID tag in response to the polling signal, wherein the reflected signal comprises an identifier unique to the RFID tag;

determining whether a reflected signal from the RFID tag comprising the RFID tag identifier is received at the alert module;

issuing an “object-not-present” signal from the alert module with respect to the object if the RFID tag identifier associated with the object is not received;

in response to the object-not-present signal, identifying the RFID tag as non-responsive; resending the polling signal; and

if the RFID tag identifier is not received after at least one resend attempt, then issuing an object-not-present alert with respect to the non-responsive RFID tag.

17. An identification system comprising:

a sonic identification tag, wherein the sonic identification tag comprises a piezoelectric sensor, a power storage unit, a transmission circuit and a tag identifier, and wherein the sonic identification tag is configured for:

receiving a sonic polling signal;

generating an electric current in response to the sonic polling signal;

storing an electric charge in the power storage unit; and

sending a response signal from the transmission circuit, wherein the response signal comprises the tag identifier; and

an alert module comprising:

a memory comprising the tag identifier;

a sonic polling signal generator, wherein the sonic polling signal generator comprises instructions for sending the polling signal;

a receiver configured for receiving the response signal from the sonic tag;

a separation manager comprising instructions for:

determining whether the response signal comprising the sonic tag identifier has been received; and

issuing an “object-not-present” signal if the response signal comprising the sonic tag identifier has not been received,

in response to the object-not-present signal, identifying the sonic tag as non-responsive;

resending the polling signal; and

if the sonic tag is not received after at least one resend attempt, then issuing an object-not-present alert with respect to the non-responsive sonic tag.

18. The identification system of claim 17 , wherein the object-not-present alert is selected from the group consisting of an audible alarm and a visual alarm.

19. The identification system of claim 18 , wherein the audible alarm is a synthesized voice.

20. The identification system of claim 17 , wherein the object-not-present alert is a visual alarm.

21. The identification system of claim of claim 20 , wherein the visual alarm is a text message.

22. The identification system of claim 17 , wherein the object-not-present alert identifies the monitored object that is associated with the monitoring module.

23. The identification system of claim 17 , wherein the alert module further comprises instructions for:

accepting an object-not-present alert cancel request from a user;

determining whether a reflected signal comprising the sonic tag identifier has been received; and

issuing an object return alert if the reflected signal comprising the sonic tag identifier has been received.

24. The identification system of claim 17 , wherein the alert module is incorporated into a portable device.

25. The identification system of claim 24 , wherein the portable device is selected from the group consisting of a cellular telephone, a PDA, a laptop computer, a portable music player, and a wristwatch.

26. The identification system of claim 17 , wherein the alert module further comprises instructions for:

prior to resending the polling signal, increasing the polling signal signal strength by a preset increment;

resending the polling signal; and

if the sonic tag identifier is not received after the polling signal signal strength reaches a maximum signal strength level, then issuing the object-not-present alert with respect to the non-responsive sonic tag.

27. The identification system of claim 17 , wherein the alert module further comprises instructions for:

prior to resending the polling signal, increasing the receiver sensitivity by a preset increment;

resending the polling signal; and

if the sonic tag identifier associated with the object is not received after the receiver sensitivity reaches a maximum sensitivity, then issuing the object-not-present alert with respect to the non-responsive sonic tag.

28. A method of identifying an object comprising:

sending a sonic polling signal from a sonic polling signal generator;

receiving a sonic polling signal at a sonic identification tag;

generating an electric current in response to the sonic polling signal;

storing an electric charge in the power storage unit;

sending a response signal from the transmission circuit, wherein the response signal comprises a sonic tag identifier;

receiving the response signal from sonic identification tag;

determining whether the response signal comprising the sonic tag identifier has been received; and

issuing an “object-not-present” signal if the response signal comprising the sonic tag identifier has not been received,

in response to the object-not-present signal, identifying the sonic tag as non-responsive;

resending the polling signal; and

if the sonic tag identifier is not received after at least one resend attempt, then issuing an object-not-present alert with respect to the non-responsive sonic tag.

29. An electronic tether comprising:

a first monitoring module comprising a first RFID tag and a second monitoring module comprising a second RFID tag, wherein the first RFID tag is configured to receive a polling signal and to transmit a first reflected signal in response to the polling signal and wherein the second RFID tag is configured to receive the polling signal and to transmit a second reflected signal in response to the polling signal, and wherein the first reflected signal comprises an first identifier unique to the first RFID tag and the second reflected signal comprises an second identifier unique to the second RFID tag; and

an alert module comprising:

a memory comprising the first and second RFID tag identifiers;

an RFID tag polling manager comprising instructions for sending the polling signal;

a receiver configured for receiving the first and second reflected signals from the first and second RFID tags;

a separation manager comprising instructions for:

determining whether the first reflected signal comprising the first RFID tag identifier has been received;

issuing a first “object-not-present” signal with respect to the first alert module if the first reflected signal comprising the first RFID tag has not been received;

in response to the first object-not-present signal, identifying the first RFID tag as non-responsive;

determining whether the second reflected signal comprising the second RFID tag identifier has been received;

issuing a second “object-not-present” signal with respect to the second alert module if the second reflected signal comprising the second RFID tag has not been received;

in response to the second object-not-present signal, identifying the second RFID tag as non-responsive;

if either the first or second RFID tags have been identified as non-responsive, then resending the polling signal;

if the first RFID tag identifier is not received after at least one resend attempt, then issuing a first object-not-present alert with respect to the first non-responsive RFID tag; and

if the second RFID tag identifier is not received after at least one resend attempt, then issuing a second object-not-present alert with respect to the second non-responsive RFID tag.

30. The electronic tether of claim 29 , wherein the first object-not-present alert and the second not present alert is an audible alarm.

31. The electronic tether of claim 30 , wherein the audible alarm is a synthesized voice.

32. The electronic tether of claim 29 , wherein the first object-not-present alert and second not present alert are visual alarms.

33. The electronic tether of claim 32 , wherein a visual alarm is a text message.

34. The electronic tether of claim 29 , wherein the first object-not-present alert identifies the monitored object that is associated with the first monitoring module.

35. The electronic tether of claim 29 , wherein the alert module further comprises instructions for:

accepting a first object-not-present alert cancel request from a user with respect to the first alert module;

determining whether a first reflected signal comprising the first RFID tag identifier has been received; and

issuing an object return alert with respect to the first alert module if the first reflected signal comprising the first RFID tag identifier has been received.

36. The electronic tether of claim 29 , wherein the alert module is incorporated into a portable device.

37. The electronic tether of claim 36 , wherein the portable device is selected from the group consisting of a cellular telephone, a PDA, a laptop computer, a portable music player, and a wristwatch.

38. The electronic tether of claim 29 , wherein the polling manager comprises means for varying the polling signal signal strength and wherein the alert module further comprises instructions for establishing a preset separation distance between the alert module and the first and second monitoring modules by adjusting the polling signal signal strength.

39. The electronic tether of claim 29 , wherein the receiver comprises means for varying the receiver sensitivity to the reflected signal and wherein the alert module further comprises instructions for establishing a preset separation distance between the alert module and the first and second monitoring modules by adjusting the receiver sensitivity.

40. The electronic tether of claim 29 , wherein the at least first and second RFID tags are selected from the group consisting of a passive RFID tag, a semi-passive RFID tag, and an active RFID tag.

41. The electronic tether of claim 29 , wherein the alert module is further comprises instructions for:

prior to resending the polling signal, increasing the polling signal signal strength by a preset increment; resending the polling signal

if the first RFID tag identifier is not received after the polling signal signal strength reaches a maximum signal strength level, then issuing the object-not-present alert with respect to the first non-responsive RFID tag; and

if the second RFID tag identifier is not received after the polling signal signal strength reaches the maximum signal strength level, then issuing a second object-not-present alert with respect to the second non-responsive RFID tag.

42. The electronic tether of claim 29 , wherein the alert module is further adapted to:

prior to resending the polling signal, increasing the receiver sensitivity by a preset increment;

resending the polling signal;

if the first RFID tag identifier is not received after the receiver sensitivity reaches a maximum sensitivity, then issuing the object-not-present alert with respect to the first non-responsive RFID tag; and

if the second RFID tag identifier is not received after the receiver sensitivity reaches the maximum sensitivity, then issuing a second object-not-present alert with respect to the second non-responsive RFID tag.

43. The electronic tether of claim 29 , wherein:

a first preset preset separation distance is established by selection of the first RFID tag based on a measure of signal strength of the reflected signal of the first RFID tag; and

a second preset preset separation distance is established by selection of the RFID tag based on a measure of signal strength of the reflected signal of the second RFID tag.