WIRELESS SENSORS FOR SYSTEM MONITORING AND DIAGNOSTICS

• US 20040130458A1
• Filed: 12/19/2002
• Published: 07/08/2004
• Est. Priority Date: 12/19/2002
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: CHEUNG, Patrick C.P., KOUTSOUKOS, Xenofon
• Granted Patent: US 7,548,171 B2
• Time in Patent Office: Days
• US Class Current: 340/870.01
• CPC Class Codes: G08C 17/02 using a radio link

Abstract

A plurality of wireless sensors can be placed within a large system in various locations to monitor critical elements of that system. Each wireless sensor can include sensor elements usable to monitor one or more parameters of an element of the system and a wireless signal transmitter, such as, for example, a speaker or an antenna. Each sensor can transmit one or more unique identifying signals to a signal-receiving device, which can be processed by a signal processor. The signal processor can determine each received signal, the sensor corresponding to that identified signal, and the time the wireless signal was generated. Based on this information, the wireless signals can be diagnostically compared against expected values for the system being monitored and evaluated. If a discrepancy is detected, then the components and/or subsystems within the system that are implicated in the discrepant wireless signals can be evaluated for possible errors.

Claims

1. A wireless sensor system usable to sense a parameter of a second system and to wirelessly transmit sensed information, comprising:

a plurality of sensor subsystems, each sensor subsystem wirelessly transmitting information on at least one frequency that is unique to that sensor subsystem; and

a signal processor subsystem that receives the wirelessly transmitted information from the plurality of sensor subsystems, wherein the signal processor determines which of the plural of sensor subsystems transmitted a particular element of information based on the frequency used to transmit the element of information.

2. The wireless sensor system of claim 1, wherein the signal processor subsystem determines a time that the particular element of information was transmitted and determines information about the second system based on elements of information transmitted by at least some of the plurality of wireless sensor subsystems and the corresponding times of transmission.

3. The wireless sensor system of claim 1, wherein the signal processor subsystem determines information about the second system based on elements of information transmitted by at least some of the plurality of wireless sensor subsystems and corresponding times of transmission of those elements of information.

4. The wireless sensor system of claim 1, wherein:

each of at least some of the plurality of wireless sensor subsystems comprises an audio transmitter that outputs a sound signal; and

the signal processor subsystem comprises at least one microphone that is capable of sensing the sound signals transmitted by the at least some of the wireless sensor subsystems.

5. The wireless sensor system of claim 4, wherein each of the at least some of the sensor subsystems outputs at least one audible-frequency sound signal.

6. The wireless sensor system of claim 5, wherein each of the at least some of the sensor subsystems outputs at least two audible-frequency sound signals having different frequencies.

7. The wireless sensor system of claim 1, wherein:

each of at least some of the plurality of wireless sensor subsystems comprises a transmitter that outputs an electromagnetic signal; and

the signal processor subsystem comprises at least one antenna that is capable of sensing the electromagnetic signals transmitted by the at least some of the wireless sensor subsystems.

8. The wireless sensor system of claim 7, wherein each of the at least some of the sensor subsystems outputs at least one electromagnetic signal.

9. The wireless sensor system of claim 8, wherein each of the at least some of the sensor subsystems outputs at least two electromagnetic signals having different frequencies.

10. The wireless sensor system of claim 7, wherein each of the at least some of the sensor subsystems outputs at least one radio-frequency electromagnetic signal.

11. The wireless sensor system of claim 1, wherein each of at least some of the plurality of sensor subsystems comprises a multiple frequency signal generator that is capable of generating a plurality of signals at different frequencies.

12. The wireless sensor system of claim 11, wherein each of the at least some of the plurality of sensor subsystems further comprises:

a sensor that outputs a plurality of different sensor signals based on a condition of the sensed parameter; and

a signal processor that operates the multiple frequency generator to transmit a wireless signal at one of the plurality of frequencies based on the output sensor signal.

13. The wireless sensor system of claim 11, wherein the multiple frequency signal generator is capable of generating a plurality of electromagnetic signals at different frequencies.

14. The wireless sensor system of claim 13, wherein the multiple frequency signal generator is capable of generating a plurality of radio-frequency electromagnetic signals at different frequencies.

15. The wireless sensor system of claim 11, wherein the multiple frequency signal generator is capable of generating a plurality of sound signals at different frequencies.

16. A method for wirelessly sensing a parameter of a sensed system, comprising:

sensing the parameter using a plurality of wireless sensor devices, each wireless sensor device capable of sensing a condition of the parameter;

outputting a wireless signal based on the sensed condition from each wireless sensor device at at least one frequency that is unique to that wireless sensor device;

receiving a plurality of the wireless sensor signals from at least some of the plurality of wireless sensor devices;

determining a frequency of each of the received wireless sensor signals; and

determining which of the plurality of wireless sensor devices output the received wireless sensor signals based on the determined frequencies for the received wireless sensor signals.

17. The method of claim 16, further comprising determining, for each received wireless sensor signal, a time when that wireless sensor signal was output by the determined wireless sensor device corresponding to that received wireless sensor signal.