DESCRIPTION
TITLE OF INVENTION SENSOR DEVICE
TECHNICAL FIELD
coo0 11
The present invention relates to a sensor device to measure a physical quantity in
the outside. More specifically, it relates to a sensor device to receive an acquisition request for
5 a physical quantity from a plurality of request sources.
BACKGROUND ART
[0002]
Due to promotion and the like of a smart city and an Intelligent Transportation
10 Systetn (ITS), the environment buried sensor will be further expectedly developed. In this
situation, there has been proposed a method to efficiently collect information from sensors
widely dispersed in, for example, a road, a building, a railroad, a station, water pipes for water
and sewage, a pipeline, or an airport.
[0003]
1 5 For example, patent literature 1 describes an example of the information
collecting method. In patent literature 1, there has been described a technique in which an
acquisition request for information of a sensor at a desired position is issued from a remote post
connected to a fixed network by use of a query; and when a query transferred from a proxy
dcvice to a mobile body having registered positional information matched to an area designated
20 by this query is received, the sensor information received by the pertinent mobile body is
transmitted via the fixed network to the remote post that is the transmission source of the
received query. It has been described that by using such information collecting method, a
particular request source is capable of collecting information from a sensor in a particular area
and in a particular time zone.
25 [0004]
Patent literature 2 describes a method to collect information by designating a
particular sensor. Specifically, there has been described a method in which a mobile reader
collects identification information of a ubiquitous node sucl~a s an RFID located in a
communication area thereof and requests, based on the identification information, information
transmission by designating a pal-ticular ubiquitous node. It has been described that by
applying this niethod, it is possible to prevent collision of information at transmission of
originating information and it is possible to reduce power consumption since information is
transmitted only when a request is received.
5
CITATION LIST
[0005l
PATENT LITERATURE 1 JP-A-2004-362267
PATENT LITERATURE 2 JP-A-2006-304 168
10
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0006]
However, for a sensor system in which a plurality of request sources issue an
15 acquisition request for information to one and the same sensor, no report example has been
Sound. Particularly, no report example has been found for a problen~ in a situation in which a
plurality of request sources install sensors to output almost equal information for different
purposes in adjacent places as well as a problem of maintenance and management of sensors in
association with use of a tremendously large number of sensors.
20 [0007]
For example, in roads, facilities of different managing companies such as water
pipes for water and sewage and gas plumbing are buried and the road mmaging company installs
sensors to manage roads, and the water and sewage managing company and the gas plumbing
~iianagingc ompany install sensors to manage water and sewage. These sensors, although
25 having different installing purposes and request sources, measure physical quantities common
thereto such as temperature, humidity, and vibration in many cases.
[0008]
Further, when burying the sensors in the environment, the wiring work for power
sources and output signal lines is difficult in many cases; hence, recently, there has been adopted
30 in many cases a transmission and reception scheme for measured information by using radio
communication driven by batteries. However, for a sensor using a battery, since it is required to
replace the battery sooner or later, the periodical maintenance and repair is required for the
sensor. Also, depending on the utilization frequency and the utilization period of the sensor,
there arises a problem of deterioration in reliability of the measured information due to
4
deterioratio~in~ sensor performance. In addition, in a situation wherein a plurality of request
sources, which do not mutually share information, access one and the same sensor, it is difficult
to grasp how long the sensor has been used. Moreover, also for the replace work of the sensor,
it is required that the history of the installation place, installation time, and the like of the sensor
5 is managed for each sensor for a long period of time and to precisely instruct wliich ones of the
tremendously large number of sensors are to be replaced.
100091
As above, in the sensor system in which a plurality of request source issues an
acquisition request for information to one and the same sensor, it is required to consider the
10 problems which are not taken into consideration in the prior art. The object of the present
invention is to provide a sensor device suitable for the sensor system above.
SOLUTION TO PROBLEM
[OO 1 01
15 Representative means to solve the problem according to the invention of the
present application will be exemplified as a sensor device, characterized by comprising a
physical quantity sensing unit to measure a physical quantity in the outside; an input-output unit
to receive an acquisition request for the physical quantity from a plurality of request sources in
the outside; and a first counter which counts and stores the total of the number of operations
20 conducted by the input-output unit to receive the acquisition request from the plurality of request
sources, wherein the input-output unit transmits to the request source of the acquisition request,
t11e physical quantity and the value stored in the first counter.
ADVANTAGEOUS EFFECTS OF INVENTION
25 [OOll]
According to the invention of the present application, it is possible to provide a
sensor device more suitable for a sensor system in which a plurality of request sources issue an
acquisition request for information to one and the same sensor.
30 BRIEF DESCRIPTION OF DRAWINGS
[OO 1 21
[FIG. I] FIG. 1 is a schematic overall configuration diagram of a sensor with
counter in a first embodiment.
[FIG. 21 FIG. 2 is a configuration diagram of the sensor with counter in the first
embodiment.
[FIG. 31 FIG. 3 is a correlation diagram of a sensor with counter in a second
embodiment.
[FIG. 41 FIG. 4 is a flowchart of information of the sensor with counter in the
5 second en~bodiment,
[FIG. 51 FIG. 5 is a correlation diagram of an information transmission history
storing unit of the sensor with counter in the second embodiment.
DESCRIPTION OF EMBODIMENTS
10 [00131
I11 tlie c~libodi~iienbtse low, if necessary for convenience, the embodiment will be
divided into a plurality of sections or embodiments in the description; Iiowever, excepting tlie
case that is particularly demonstrated, these are not independent of each other, but are in a
relationsl~ipin which one is a variation(s) of part or all of the other, a detailed description, a
15 supplementary description, or tlie like.
[00141
Also, in the embodiments below, when the number of elemeilts and the like
(including the number, the numeric value, the quantity, the range, and the like) are cited,
excepting the case that is particularly demonstrated, the case in which the embodiment is clearly
20 liniited in principle to the particular number, and the like, the e~i~bodimeinst n ot li~i~itctod tlie
particular number, but the number may be more than or less than the particular number.
[0015]
Additionally, in the embodiments below, the constituent components (including
component steps and the like) are not necessarily required, excepting the case that is particularly
25 demonstrated, the case in which the components are clearly required in principle, and the like.
100 1 61
Similarly, in the embodiments below, when contours, positional relationships, and
the like of the constituent components are cited, excepting the case that is particularly
demonstrated, the case in which the components are obviously inappropriate in principle, and the
30 like, it is assumed that those substantially approximate to or analogous to the contours or the like
are included. This also applies to the numeric value and the range described above.
[OO 1 71
Moreover, in all drawings to explain the embodiments, the same reference
numerals are assigned to the same members in principle, and redundant explanation thereof will
be avoided to the maximum extent. Next, description will be given in detril of embodiinents of
the present invention by use of the drawings and the flowchart.
FIRST EMBODIMENT
yo0 1 81
5 Description will be given of a sensor with counter in the first embodiment of the
present invention by referring to the drawings. FIG. 1 is a schematic diagram showing an
overall configuration of a sensor with counter S1 as an example of the sensor device in
accordance with thc present invention.
[00 191
10 The sensor with counter S 1 of the present embodiment includes a physical
quantity sensing unit 1 to measure physical quantities such as temperature, pressure, velocity,
positions, acceleration, angular velocity, and the like required to maintain and to repair
infrastructure such as a road, a building, a bridge, water pipes for water and sewage, gas
plumbing, and the like; an ID retaining unit 2 to identify a sensor, an information transmission
15 history storing unit 3 in which the value changes in association with an acquisition request from
the outside, and an input-output unit 4 which conducts, by wire or by radio, reception of an
acquisition request from the outside and transmission of the measured value from the physical
quantity sensing unit 1, a sensor ID, and information transmission history information.
[OO2O]
2 0 Description will be given of respective constituent coinponents of the sensor S 1.
[O02 11
The physical quantity sensing unit 1 includes a temperature sensing unit based on
the principle of the already well known thermistor and the thermocouple scheme, a pressure
sensing unit which senses the variation of external pressure through the quantity of deformation
25 of a diaphragm or the like as a change of electrostatic capacity or a change of electric resistance
value, a humidity sensing unit which uses a change in permittivity or conductivity due to
absorption of water by a humidity sensing body, a velocity sensing unit which uses the Doppler
phenomenon, positional information due to position measurement by GPS or positional
infor~lnatioilb eforehand stored in the sensor, an acceleration and angular velocity sensing unit to
30 sense the positional change of a mobile body based on a change of electrostatic capacity or the
like, and all of or a combination of part of the gas sensing units to measure a change of
conductivity caused by a chemical reaction between a particular gas and a catalyzer; and the
physical quantity sensing unit 1 stores therein physical quantities sensed by these sensing units
by use of a non-volatile memory, not shown.
7
100221
Next, the ID retaining unit 2 of the sensor is a non-volatile memory to store
therein a unique value to identify a sensor, and the owner of the sensor manages the installatioii
place, the installation time, and the like of the sensor by use of the value stored in the ID
5 retaining unit 2 of the sensor.
(00231
Next, description will be given of the information translnission liistory storing
unit 3. The inforii~ationtr ansmission history storing unit 3 is equipped with a counter 30 tlie
numeric value of which is increased by one each time information is outputted from the sensor
10 S1 in response to an event in which an acquisition request for a physical quantity from the
outsidc sensed by tlie physical quantity sensing unit is inputted to the input-output unit 4, which
will be described later. FIG. 2 is a schematic diagram showing a configuration of the counter
30. The counter 30 is configured by including a non-volatile memory 3 1 to store therein
counter information even when the power source is lost, a provisional meinory 32, and a counter
15 circuit 33 en~ployinga flip-flop circuit. When an acquisition request is inputted fro111 the
outside to the counter 30 configured as above, the counter information stored in the non-volatile
niemory 3 1 is dumped in the cache 32 as a provisional storing place. Thereafter, the counter
circuit 33 increases the numeric value stored in the cache 32 by one, and the value of the cache
32 is again stored in tlie non-volatile memory 3 1. Here is shown a configuration as an example
20 of tlie counter including the counter circuit of flip-flop type 33, the cache 32, and the nonvolatile
meinory 3 1 configured using a flash memory or the like; howevel-, according to the gist
of the present invention, it is only necessary that the value in the sensor is changed and the value
is stored in response to an acquisition request from the outside by use of some means, and is not
limited to the configuration of the counter 30 shown in FIG. 2.
25 100241
Here, the counter 30 shown in FIG. 2 is characterized in that without
discriinil~atingt lie request source of the acquisition request, the counter 30 counts and stores the
total of the number of operations conducted to receive the acquisition request for a physical
quantity from a plurality of request sources. Advantageous effects due to the sensor SI
30 including the counter 30 above will be described later. Also, as will be explained in
conjunction with the second embodiment, it is possible to dispose a counter which further
discrilninates the request source and which counts and storcs, for each of the request sources, the
total of the number of operations conducted to receive the acquisition request.
roo251
Next, the input-output unit 4 will be described. The input-output unit 4 receives
by wire or by radio an acquisition request from the outside and transmits to the request source,
by wire or by radio, information of a physical quantity measured by the physical quantity sensing
unit I , the value store in the ID retaining unit 2, and the value stored in the non-volatile memory
5 3 1 of the counter 30. Here, the request source corresponds to the mobile body indicated in the
information collecting technique of patent literature 1. Specifically, it is an information
collecting terminal (such as a car navigation system including a two-way communication
function) to be mounted on a running car or a cellular phone carried around by a walking person.
The informatioil collected by these information collecting terminals is transinitted to a remote
10 host via a fixed network also disclosed by the prior art. Here, the remote host corresponds to a
managing company to manage roads and pipelines by use of information from the sensor S 1.
Naturally, the information may be collected in the method disclosed by patent literature 1 or
patent literature 2 cited in the present application; however, the sensor with counter S 1 of the
first ernbodinlent is not restricted by the information collecting methods of patent literature 1 and
15 patent literature 2.
COO261
Subsequently, description will be given in detail of the advantageous effects
obtained by using the sensor device according to the present embodiment.
roo271
2 0 The sensor device according to the present embodiment includes as described
above a counter not discriminating the request source of the acquisition request. The counter
serves a function as so-called an absolute counter for the sensor device. Hence, when setting
life with respect to performance of the sensor device, it is possible to use the information stored
in the counter. For example, in the sensor S 1, through repetitious activation and repetitious
25 radio transmission, there take place deterioration of electronic parts of various electronic circuits
including transistors and OP amplifiers and a change with the passage of time in the state of
packaging such as an event in which a fixing position is loosened. When these changes exceed
a fixed level, the sensor 1 reaches the end of life with respect to performance; as the judge
criterion for this, it is possible to use the value of the counter 30, and based on the information,
30 the sensor S 1 may be replaced in the same way as for the replacement of the battery.
[0028]
Further, when collecting environmental information from a designated area, it can
be considered that information is received from a plurality of sensors S 1. In this situation,
depending on a phenomenon to be analyzed, the phenomenon analysis may also be conducted
with higher reliability by selecting for use the information for which the value of the counter 30
is younger or is within a fixed range.
100291
Moreover, as the number of environment buried sensors becomes larger, power
5 source work and wiring work for data input-output lines become more difficult; hence, there are
required environment buried sensors which are driven by a battery and which are capable of
conducting radio transniission and reception. Hence, it can be considered that the sensor S 1 is
driven by a battery. In this situation, the sensor S 1 ordinarily waits for operation in a slip mode,
to lower consumption of the battery to the maximum extent. In this state, when an acquisition
10 rcquest is inputted from the outside to the input-output unit 4 of the sensor S 1, the mode thereof
changes to the activation mode, to translnit inforn~ationto the request source. In this situation,
the quantity of consumed power required for the one activation and infolamation transmission can
be easily calculated or measured; hence, it is possible to calculate, based on the capacity of the
battery disposed, the number of operations for information transmission and activation which can
15 be conductcd. That is, by using tlie infonilation (counter information) recorded in the counter
30, the number of uses thereafter can be predicted. The managing company to maintain and to
repair the sensor S 1 can replace the sensor S 1 or the battery thereof in the coverage area of the
company while referring to the counter information on site. Particularly, in a situation in which
the owner of the sensor S 1 differs fiom the managing company in charge of tlie maintenance and
20 repair, even when detailed information such as tlie history and the installation place of the sensol-
S1 are not supplied, the job can be carried out based on the sensor position and the counter
information which can be confirmed from a wireless terminal on site in the coverage area; hence,
it is possible to reduce the cost required for the maintenance and repair of the sensor S 1. The
counter 30 shown in FIG. 2 can be configured, although not shown, by a combination of a first
25 counter circuit which keeps the value stored therein even when the battery is replaced and the
stored value of which continuously increases from when it is set to zero at delivery thereof to
when it reaches the end of life and a second counter circuit the stored value of which is set to
zero by a comnland from the outside when the battery is replaced or the like. In this situation,
after the replacement of the battery, by setting the value of the second counter circuit to zero, it is
30 possible to know the replacing time of the battery based 011 the value of the second counter
circuit.
[0030]
'The sensor with counter according to the present embodiment can fulfill the
advantageous effects of the present invention in a situation in which a plurality of infrastructure
managing companies install environmelit buried sensors in mutually overlar~piligp articular areas
and the respective infrastructure managing companies can independently access the sensors of
each other (can sliare the sensors) and the maintenance and repair of a sensor under consideration
is conducted for each area by a sensor repair company other than the infrastructure inanaging
5 conlpanies described above. A detailed operation mode and the like will be described in detail
in conjunction with the other embodiment.
(003 11
As described above, by assigning the counter function to the environment buried
sensor, it is possible to conduct highly reliable information analysis and to considerably reduce
10 the cost required for the maintenance and repair of the sensor.
SECOND EMBODIMENT
[0032/
The second embodiment will be described by referring to FIGS. 3 to 5. In this
connection, the items which are described in the first embodiment and which are not described in
15 the present embodiment also applies to the present embodiment unless particular reasons are
present. FIG. 3 is a diagram schematically showing the main configuration associated with
operations such as sharing and maintenance and repair of the sensor with counter according to
the present embodiment.
[003 31
20 In the second embodiment, it is assumed that there exist a plurality of
infrastructure managing companies 11 3, 114 and the respective infrastructure managing
companies 11 3, 114 install, in order to measure environments of the infrastructure under control
thereof, sensor devises according to the present embodiment as environment buried sensors 12 1,
123, 125, 127, 129 and 122, 124, 126, 128, 130 in areas 1 and 2. Although not particularly
25 limited, to easily image the contents of the invention, it is assumed that the managing company
1 13 is a road enterprise and the managing company 1 14 is an enterprise for water and sewage
and gas. In general, pipes of water and sewage and gas plumbing are buried under or beside a
road in many cases. While the managing companies 113, 114 install, in order to collect
information of maintenance and repair of the road or the plumbing, the environment buried
30 sensors 121 to 130, it is required to install many sensors to obtain information with high
precision. However, when each of the companies installs and manages many sensors, there are
required tremendously high initial installation cost and tremendously high maintenance and
repair cost.
[0034]
The information required for the maintenance and repair of roads includes as
environmental information such as temperature, humidity, and vibration; also for the
maintenance and repair of water and sewage and gas plumbing, the required information
includes information required for gas leakage sensing and many items common to the
5 information required for the road management such as temperature, humidity, and vibration.
Hence, when the managing companies 11 3, 114 share the sensors 121 to 130 of each other, it is
possible, wliile suppsessing thc initial jnstallation cost and the sensor maintenance and
rnanagenient (operation) cost, to obtain information with high precision.
100351
10 Also, for the maintenancc and repair of environment buried sensors, it is efficient
that cach of the infrastructure managing companies 11 3, 114 does not independently conduct the
maintenance and repair and the area is divided such that different special repair companies
conduct the maintenance and repair for the respective areas (area 1,area 2). For example, the
area is favorably divided for each of the self-governing bodies such as a prefecture, a ward, and a
15 city. Here, a situation in which the areas 1 and 2 shown in FIG. 3 indicate areas associated with
distance of several meters to several tens of meters, which are communicable distance between
the mobile bodies 13 1, 132 and the environment buried sensors 12 1 to 130 and a situation in
which they indicate areas of a prefecture, a ward, and a city as the coverage ranges of repair
companies 14 1, 142 of the sensors are mixedly employed.
20 (00361
111 conjunction with the present embodiment, description will be given in detail of
the function of the sensor with counter in a situation wherein the plurality of infrastructure
managing companies (1 13, 114) install the environment buried sensors (1 2 1 to 130) in the
particular areas (area 1 ,area 2) in which the coverage areas overlap with each other, and are
25 capable of mutually and independently accessing the sensors (sharing the sensors); moreover, the
sensor maintenance and repair is conducted for the respective areas (area 1 ,area 2) by thc sensor
repair companies 141,142 (not shown) different from the infrastructure managing companies
(113, 114).
[0037]
30 FIG. 4 is a correlation diagram to explain the sensor with counter S2 and the flow
of measured information in the present embodiment. Details will be described by also using the
operation diagram of the sensor with counter S2 of FIG. 3 and the configuration diagram of the
information transmission history storing unit 3 of FIG. 5. First, the infrastructure managing
companies 113, 1 14 transmit request source IDS (1 13,114) and areas (area1,area 2) and time
zones for the lneasurenlent of environment information, to contracted gateways 134, 135. Here,
the gateways 134, 135 correspond to locations such as cellular phone enterprises which have
grasped the positions of the mobile bodies 13 1, 132.
[003 81
5 The gateways 134, 1 35 transmit, based on the acquisition requests froin the
infrastructure managing coinpanies 1 13, 11 4, IDS of the gateways 134, 135 or IDS of the
infrastructure managing companies 11 3, 114 as the request sources and the associated mobile IDS
(1 3 1,132) to the mobile bodies 13 1, 132 whicl~a re running or walking in the designated areas
(areal ,area 2) and in the designated time zones.
10 [0039]
The mobile bodies 13 1, 132 issue information requests to the environinent buried
sensors by transmitting, as acquisition requests to the sensors, the IDS of the gateways 134, 135
or the IDS of the infrastructure managing companies 113, 114 as the request sources.
[00401
15 When the IDS of the gateways 134, 135 or the IDS of the infrastructure managing
companies 1 13, 1 14 as the request sources have been installed in the information transmission
history storing units 3 of the sensors 121 to 130 shown in FIG. 5 and have been registered to an
access right Judge unit 10 which is a non-volatile memory to store therein the respective IDS of
the request sources, the environment buried sensors 121 to 130 increase the values of counters
20 40-NO corresponding to the request sources by one and the value of counter TO storing the total
access count by one and transmit the values stored in the sensor ID retaining unit 2, the
environment measured value from the physical quantity sensing unit 1, and the counter
information to the mobile bodies 13 1, 132.
1004 1 ]
25 The mobile bodies 13 1, 132 return, to the gateways 134, 135, the information
from the environment buried sensors 121 to 130, and according to necessity, information of the
sensors incorporated in the mobile bodies 13 1, 132, time information, and the IDS of tlie mobile
bodies 13 1, 132.
[0042]
30 The gateways 134, 135 add the IDS of the gateways 134, 135 to the information
from the mobile bodies 13 1, 132 and then return the resultant information to the infrastructure
managing companies 11 3, 11 4 as the request sources.
100431
As above, the sensor device according to the present embodiment is characterized
13
by including, in addition to counter TO which counts and stores therein the total of the number of
operations conducted to receive the acquisition request from a plurality of request sources, a
plurality of counters 40 to NO each of which counts and stores therein, for each of the plurality of
request sources, thc total of the nurnber of operations conducted to receive the acquisition
5 request. Due to the characteristic, it is possible to measure life of the sensor device by use of
the value stored in counter TO; further, the counters 40 to NO make is possible to conduct
accounting of the quantity of information for each of the request sources.
roo441
And, by using the sensor device above and by using the information flow and the
10 operation of information described above, the infrastructure managing companies 11 3, 114 are
capable of acquiring the environmental information in the required places and in the required
time zones while inutually sharing the sensors of each other.
[0045]
Further, although any detailed scheme will not be described, since the information
15 path is unmistakable, the information charge may be paid by the respective parties concerned, in
a shared fashion according to necessity. Also, since the infrastructure managing companies
1 13, 114 can mutually and independently access the sensors of each other, even when there exists
no competitive relationship or no information exchange, it is possible to collect environmental
data by using the sensors of each other without leaking information.
20 roo461
In the access right judge unit 10 shown in FIG. 5 of the inforillation transmission
history storing unit 3; although not shown, based on the information from the outside of the
sensor device, an additional ID and an associated counter thereof rnay be registered later or an
unnecessary ID and its associated counter may be deleted. Hence, when assigning the access
25 right to sensors to a new infrastructure managing company, it is only necessary to additionally
register an ID to the access right judge unit 10.
[0047]
Next, description will be given of a situation in which third and fourth sensor
repairing and managing companies manage the environment buried sensors 12 1, 123, 125, 127,
30 129 and the environment buried sensors 122, 124, 126, 128, 130 owned by different owners, for
the respective areas (area 1 ,area 2). For example, for the environment buried sensors buried in
a wide range of a national road and an express highway, a plurality of infrastructure managing
companies 11 3, 114 entrust the sensor repair job to special sensor repair companies 141, 142 (not
shown) for each area (area 1 ,area 2) depending on cases. The sensor repair companies 14 1, 142
receive information required for the replacement and repair (battery replacement) of the sensors
from the respective infrastructure managing companies 11 3, 114 and carry out the actual job.
[0048]
However, in a situation in which the environment buried sensors 121 to 130 are
5 shared between the plural infrastructure managing companies 1 13, 1 14, in order to grasp the
utilization frequency and the like of the sensors, coniplicated procedures are required, for
example, it is required that the infrastructure managing companies 11 3, 11 4 share the access
histories corresponding to IDS of the sensors. Here, by using the counter information, it is only
required to replace the sensors each of which exceeds the number of operations beforehand
10 instructcd by the infrastructure managing con~panies 11 3, 114; hence, the maintenance and
managemcnt can bc conducted for the sensors even when complicated job instructions are not
given.
[00491
Incidentally, although the details will not be again described, also in the sensor
15 wit11 counter S2 of the present embodiment, there can be obtained advantageous effects similar to
those obtained when the counter information described in co~ljunctionw ith the first embodiment
is employed.
REFERENCE SIGNS LIST
20 (ooso]
S 1 : Sensor with counter, S2: Sensor with counter, 1 :Physical quantity sensing
unit, 2:JD retaining unit, 3:Information transmission history storing unit, 4:Input-output unit,
1O:Access right judge unit, 30:Counter, 3 1 :Non-volatile memory, 32:Cache, 33:Counter circuit,
40:Counter, 41 : Non-volatile memory, 42:Cache, 43:Counter circuit, N1: Non-volatile memory,
25 N2:Cache, N3:Counter circuit, TO:Counter, TI: Non-volatile memory, T2:Cache, T3:Counter
circuit, 11 1 :Fixed network, 11 3: Infrastructure managing company, 114: Infrastructure managing
company, 121 -1 30: Environment buried sensor, 13 1 :Mobile body, 132:Mobile body,
134:Gateway, 135:Gateway, 14 I :Sensor repair company, 142:Sensor repair company.

WE CLAIM:
[Claim 1]
A sensor device, characterized by comprising:
a physical quantity sensing unit to measure a physical quantity in the outside;
an input-output unit to receive an acquisition request for the physical quantity
from a plurality of request sources in the outside; and
a first counter which counts and stores the total of the number of operations
conducted by tlie input-output unit to receive tlie acquisition request from tbe plurality of request
sources, wherein
the input-output unit transmits to the request source of the acquisition request, the
physical quantity and the value stored in the first counter.
[Claim 2]
A sensor device according to claim I, characterized by further comprising a
second counter which counts and stores, for each of the plurality of request sources, the total of
the number of operations conducted to receive the acquisition request.
[Claim 3]
A sensor device according to claim 2, characterized by further comprising a nonvolatile
memory to store therein ID information of each of the plurality of request sources.
[Claim 4]
A sensor device according to claim 3, characterized in that the sensor device adds
ID information to the non-volatile memory or deletes the ID information stored in the nonvolatile
memory based on a command input from the outside.
[Claim 5]
A sensor device according to claim 1, characterized by further comprising a
battery to drive the sensor device, wherein
the first counter comprises a first counter circuit which retains values selected
from the values obtained by counting the number of operations conducted to receive the
acquisition request from the plurality of request sources and in which the values thus selected are
retained even when the battery is replaced and a second counter circuit in which the values
stored therein are set to zero when the battery is replaced.