Sensor node for impact detection

Inactive Publication Date: 2007-11-01
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0009] An object of the present invention, therefore, is to provide a technique regarding sensor nodes for impact detection to enable the intensities of impacts to be determined in a multi-value or analog mode and to reduce the power consumption of sensor nodes.
[0011] Since this enables power consumption by the sensor node in its waiting mode to be dramatically reduced, it is made possible to realize a sensor node for impact detection consuming very little power.
[0020] According to the invention, detection of the intensities of impacts in a multi-value or analog mode is realized, and further a technique to realize a sensor node for impact detection that can significantly reduce power consumption is achieved.

Problems solved by technology

Any such sensor node using a conventional impact detection involves a problem that, where a switch of the aforementioned type is used, only a two-value determination can be made, namely whether or not the sensed intensity of the impact has surpassed a threshold, but no multi-value or analog determination can be made.
Or where the aforementioned acceleration sensor is used, though analog determination is possible, measuring the acceleration by keeping the sensor in operation all the time involves another problem of greater power consumption, which makes it impossible to use the sensor node for a long continuous period.

Method used

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  • Sensor node for impact detection
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Examples

Experimental program
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embodiment 1

[0033]FIG. 1 is a block diagram illustrating the configuration of a sensor node for impact detection, which is a preferred embodiment of the invention.

[0034] A sensor node 101 comprises a shock detection sensor 102 configured of a piezoelectric element unit 105, a capacitor 106 and a voltage detector 107; a stand-by control object section 103 configured of a wake up signal generator 108, an impact detect circuit 113, a microcomputer 109, a radio frequency transceiver circuit 110, an A / D converter 111, a sensor 112 and other elements; and a power supply 104.

[0035] Referring to FIG. 1, the shock detection sensor 102 requires no power supply, while the stand-by control object section 103 is supplied with power by the power supply 104. Until any impact is detected, power supply is either off or in a waiting state for the radio frequency transceiver circuit 110, the A / D converter 111 and the sensor 112, in a waiting state for the microcomputer 109, and in a state of awaiting a signal f...

embodiment 2

[0038]FIG. 2 is a block diagram illustrating the configuration of a sensor node for impact detection, which is another preferred embodiment of the invention.

[0039] A sensor node 201 comprises a shock detection sensor 202 configured of a piezoelectric element unit 205, a capacitor 206 and a voltage comparator 207; a stand-by control object section 203 configured of a wake up signal generator 208, an impact detect circuit 213, a microcomputer 209, a radio frequency transceiver circuit 210, an A / D converter 211, a sensor 212 and other elements; and a power supply 204. As will be described afterwards, the capacitor 206 in the shock detection sensor 202 may not be required depending on the method of shock detection.

[0040] In this embodiment, power is fed by the power supply 204 to the voltage comparator 207 and the stand-by control object section 203 in the shock detection sensor 202. The piezoelectric element unit 205 and the capacitor 206 in the shock detection sensor 202 require no ...

embodiment 3

[0062]FIG. 10 shows one example of configuration of a sensor network system for impact detection using sensor nodes of the type shown in FIG. 1 or FIG. 2. This embodiment is configured of sensor nodes 1004 through 1006, base stations 1007 through 1009 for wireless reception of various items of information from the sensor nodes, a network 1010 to which the base stations are connected, a system control device 1011 for receiving information from the base stations via the network 1010 and processing the information into desired data, and a control information database 1012 for storing the data processed by the system control device 1011. In this embodiment, each of the sensor nodes 1004 through 1006 is installed on the object of intended detection, such as a door 1001, a cargo 1002 or a lid 1003. These objects of intended detection are mere examples, and many other items can be objects of detection.

[0063] Each of the sensor nodes 1004 through 1006, when detecting any external impact, a...

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Abstract

The invention is intended to provide a technique regarding sensor nodes for impact detection to enable the intensities of impacts to be determined in a multi-value or analog mode and to reduce the power consumption of sensor nodes. The sensor node is provided with a shock detection sensor comprising a piezoelectric element unit which generates an electric charge corresponding to an external impact, a capacitor which rectifies and accumulates the electric charge so generated, and a voltage detector which operates on the accumulated power and externally outputs a signal when the accumulated voltage reaches a preset level; a stand-by control object section which is caused by the external signal to return from a stand-by state and to operate; and a power supply which feeds power to the stand-by control object section, wherein the operation of the stand-by control object section is triggered by the signal of impact detected by the piezoelectric element unit.

Description

CLAIM OF PRIORITY [0001] The present invention claims priority from Japanese application JP 2005-085441 filed on Mar. 24, 2005, the content of which is hereby incorporated by reference into this application. BACKGROUND OF THE INVENTION [0002] The present invention relates to a sensor node technique and more particularly to a sensor node for detecting impacts. [0003] A sensor node senses information unevenly distributed in its environment at designated intervals of time, and transmits the sensed information values by wireless communication. On account of its intrinsic function to sense and transmit by wireless communication information unevenly distributed in its environment, a sensor node has to be able to operate on a battery for a long period. [0004] Conventional devices for detecting impacts arising at irregular intervals of time for use in sensor nodes detect such impacts with a mechanical switch or a switch using electric power generated by electromagnetic inductance or a piezo...

Claims

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Application Information

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IPC IPC(8): G01N3/30
CPCG01P15/0922G01P15/0891
InventorTANAKA, HIDETOSHISUZUKI, KEI
OwnerHITACHI LTD