Abstract:
A monitoring terminal device is provided which is capable of reducing its power consumption to a minimum and of being fully operated even indoors by using a solar cell as a power source. In the monitoring terminal device including a sensor unit, the transmitting unit to transmit, by wireless, a sensor monitoring output, and a control unit which control the sensor unit and the transmitting unit, further including a power supply section, when only state change of object to be monitored, that is, a output of the sensor unit is detected the control unit and the transmitting unit are started to transmit monitoring information by the sensor unit. When the sensor unit and the generating section are not activated supply of power to the sensor unit and the generating section is stopped and the control unit by itself is put into standby state, which enables reduction of power consumption to a minimum. This ensures a operation of the monitoring terminal device even in an environment in which power is not supplied from the outside

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a monitoring terminal device and more particularly to the monitoring terminal device having a sensor and a wireless communication unit to transmit, by wireless, a monitoring output fed from the sensor.  
           [0003]    The present application claims priority of Japanese Patent Application No. 2003-150062 filed on May 28, 2003, which is hereby incorporated by reference.  
           [0004]    2. Description of the Related Art  
           [0005]    Applications of communications terminals in a communication network typified by the Internet are spreading out from a personal computer and/or a portable cellular phone to an information household electrical appliance. Moreover, by placing various sensors that can observe and monitor a variety of physical quantities in every location where needed in an artificial environment and/or a natural environment and by using information fed from these sensors, it is anticipated that the artificial environment and/or the natural environment will be systematically controlled.  
           [0006]    That is, it is expected that a sensor and/or an alarm device placed in the natural environment and, moreover, various sensors and/or alarm devices placed in buildings and/or homes making up the artificial environment will be connected to a network and a monitoring output fed from these sensors and/or alarm devices will be utilized. For example, such a monitoring output can be used for managing temperatures of a paddy field or for detecting a landslide or a like in the natural environment, for checking on an opening or closing state of a window or an operating state of electrical appliances in a household environment, and for checking a state of various alarm devices at an entrance door using a portable cellular phone or a like before going out.  
           [0007]    In these sensors, when they are placed in the natural environment in particular, it is desirable that supply of power from the outside or wiring for transmission of information is no longer needed. Therefore, these sensors have to have the same function of transmitting information as a wireless transmitting device, such as a radio transmitter, and an optical transmitter, has and it is necessary that their terminals can operate for a long time without supply of power from the outside.  
           [0008]    Technology aiming at reducing power consumption in a non-contact type IC (Integrated Circuit) tag embedding a battery is disclosed in Japanese Patent Application Laid-open No. 2002-42082 (See Pages 3 and 4, and FIG. 6.) in which a sleeping state of a CPU (Central Processing Unit) in the IC tag is changed to its operating state in response to an external trigger. That is, the CPU in the IC tag is ordinarily put in the sleeping state and, only when communication between the IC tag and an external device is required, the CPU is put into its operating state by feeding a trigger to the CPU from the external device.  
           [0009]    However, the above-disclosed technology has a disadvantage. That is, in order to receive a trigger from the external device, a trigger receiving section of the CPU has to be always put in its operating state and, as a result, it is impossible to reduce power consumption in the trigger receiving section.  
         SUMMARY OF THE INVENTION  
         [0010]    In view of the above, it is an object of the present invention to provide a monitoring terminal device which is capable of reducing its power consumption to a minimum.  
           [0011]    It is another object of the present invention to provide a monitoring device which is capable of being fully operated even indoors by using a solar cell as a power source.  
           [0012]    According to a first aspect of the present invention, there is provided a monitoring terminal device including:  
           [0013]    a sensor unit;  
           [0014]    a wireless transmitting unit to transmit, by wireless, an out put from the sensor unit;  
           [0015]    a control unit to control the wireless transmitting unit; and  
           [0016]    a power source managing unit to start and control the wireless transmitting unit and the control unit in response to the out put from the sensor unit.  
           [0017]    According to a second aspect of the present invention, there is provided a monitoring terminal device including:  
           [0018]    a sensor unit;  
           [0019]    a wireless transmitting unit to transmit, by wireless, an out put from the sensor unit;  
           [0020]    a control unit to control the wireless transmitting unit;  
           [0021]    a timer to generate a starting signal in a fixed cycle; and  
           [0022]    a power source managing unit to start and control the wireless transmitting unit and the control unit in response to the output from the sensor unit and the starting signal from the timer.  
           [0023]    In the first and second aspects, a preferable mode is one that which includes a fault diagnosis signal transmitting unit to transmit a signal for fault diagnosis in response to the starting signal from the timer.  
           [0024]    Also, a preferable mode is one wherein the power source managing unit to start and control the wireless transmitting unit and the control unit in response to state change of the output from the sensor unit.  
           [0025]    Also, a preferable mode is one wherein the power source managing unit supplies power to the wireless transmitting unit and the control unit while a specified period of time after starting.  
           [0026]    Also, a preferable mode is one wherein the specified period of time is long enough for the wireless transmitting unit to transmit information.  
           [0027]    Also, a preferable mode is one wherein the power source managing unit stops power supply for components other than the sensor unit and the timer after the specified period of time has passed.  
           [0028]    Also, a preferable mode is one wherein power consumption of the sensor unit is zero in waiting state.  
           [0029]    Also, a preferable mode is one wherein the sensor unit is a lead switch or a mercury switch.  
           [0030]    Also, a preferable mode is one wherein the power source managing unit starts in response to a change in an output from the lead switch or the mercury switch.  
           [0031]    Also, a preferable mode is one that includes a power source constructed of at least one of a solar cell, a secondary cell, and a capacitor.  
           [0032]    Furthermore, a preferable mode is one wherein the solar cell is an amorphous type.  
           [0033]    With the above configurations, including the sensor unit, the wireless transmitting unit, by wireless or alike, the power supply function (solar battery or a like), and the control function, when only the sensor unit detects state change of object to be monitored, the control unit and the wireless transmitting unit are started to transmit information. After completion of transmission supply of power to the wireless transmitting unit is stopped and further the control unit by itself other than a timer of the control unit is put into standby, which enables reduction of power consumption to a minimum. This ensures an operation of the monitoring terminal device for a long time even in an environment in which power is not supplied from the outside. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0034]    The above and other objects, advantages, and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:  
         [0035]    [0035]FIG. 1 is a configuration of a monitoring terminal device according to a first embodiment of the present invention;  
         [0036]    [0036]FIG. 2 is a diagram showing an example of transmission data to be used in the first embodiment of the present invention;  
         [0037]    [0037]FIG. 3 is a diagram explaining a condition of reduction in power consumption by operating a wireless transmitting section only when a sensor unit is started and a signal for fault diagnosis is transmitted according to the first embodiment of the present invention;  
         [0038]    [0038]FIG. 4 is a diagram explaining reduction in power consumption achieved by a data transmission method employed in the transmitting unit according to the first embodiment of the present invention;  
         [0039]    [0039]FIG. 5 is a diagram explaining management of power supply made by a control unit of the embodiment of the present invention;  
         [0040]    [0040]FIG. 6 is a block diagram of a monitoring terminal device of a second embodiment of the present invention;  
         [0041]    [0041]FIG. 7 is a block diagram of a monitoring terminal device according to a third embodiment of the present invention; and  
         [0042]    [0042]FIG. 8 is a diagram explaining operations of the monitoring terminal device in FIG. 7, according to the third embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0043]    Best modes of carrying out the present invention will be described in further detail using various embodiments with reference to the accompanying drawings.  
       First Embodiment  
       [0044]    [0044]FIG. 1 is a configuration of a monitoring terminal device according to a first embodiment of the present invention. As shown in FIG. 1, the monitoring terminal device of the embodiment includes a sensor unit  10  to observe and monitor a specified kind of physical quantity, a control unit  20 , a power source unit  30 , and a transmitting unit  40 .  
         [0045]    The sensor unit  10 , which converts a physical quantity such as a temperature into an electrical signal, is made up of a sensor  101  used to output a starting signal to a power source managing section  302  by detecting a state change (a temperature change or a like) of an object to be monitored (measured). In the connection with measurement of temperatures, there is a bimetallic thermometer, as one example of the sensor  101 , and more, a proximity perception sensor using a lead switch (a opening or closing window sensor or a like), a mercury switch for detecting slope to be used for detecting tumble of a kerosene heater, and a thermistor to be used for a fire alarm or a like.  
         [0046]    The sensor unit  10  is made up of a data processing section  102  used to produce measurement data by performing data processing including an A/D (Analog to Digital) conversion of the electrical signal fed from the sensor  101 , accumulation of data, detection of a change in data, addition of information obtained from each kind of objects to be monitored (measured) (such as temperatures), or a like.  
         [0047]    The control unit  20  is made up of a control circuit  201  starts the data processing section  102  and the transmitting unit  40  after receiving power supply from the power source managing section  302  and lets the data processing section  102  and the transmitting unit  40  produce specified operation and a timer  202  outputs a starting signal to the power source managing section  302  every transmission cycle of a fault diagnosis signal.  
         [0048]    The power source unit  30  includes a power generating source/battery  301  to supply power to the sensor unit  10 , the control unit  20 , and the transmitting unit  40 . As the power generating source/the battery  301 , a solar cell, a secondary cell, a capacitor, or a combination of them or only the solar cell can be used. When the monitoring terminal device is used indoors, in particular, an amorphous-type solar cell that can absorb well spectra from a fluorescent lamp is effectively employed.  
         [0049]    The power source unit  30  also includes the power source managing section  302  feeds power supply to the control circuit  201 , the data processing section  102 ,and the transmitting unit  40  by a starting signal from the sensor  101  or the timer  202  and starts the control circuit  201 , the data processing section  102 ,and the transmitting unit  40  and stops feeding power supply to the control circuit  201 , the data processing section  102 ,and the transmitting unit  40  by a communication complete signal from the transmitting unit  40 .  
         [0050]    The transmitting unit  40  is made up of a communication data producing section  401  to produce communication data used when measurement data fed from the data processing section  102  is transmitted by a communication section  402 . In this case communication data, as one example, as shown in FIG. 2, is arranged in order of a preamble portion, a synchronizing signal for synchronization in communications, an ID (Identification) of an communication section, an ID of a sensor, an ID of a destination, a data region of the sensor, and an auxiliary data and a break of data is represented in a fixed-length format or a comma sign format. And the transmitting unit  40  is made up of the communication section  402  to transmit, by wireless (generally by wireless such as radio and light), communication data fed from communication data producing section  401 .  
         [0051]    Moreover, in FIG. 1, solid lines show a flow of data, alternate long and short dash lines show control signals, and broken lines show a flow of power supply.  
         [0052]    A physical quantity (for example, a temperature in a room) in an artificial environment or in a natural environment is converted into an electrical signal by the sensor  101  in the sensor unit  10 . Further, when detecting a state change (a temperature change or a like) of an object to be monitored, the sensor  101  outputs the starting signal to the power source managing section  302  to start feeding power supply to each section. In the connection with measurement of temperatures, there is a bimetallic thermometer, as one example of the sensor  101 , and more, a proximity perception sensor using a lead switch (a opening or closing window sensor or a like), a mercury switch for detecting slope to be used for detecting tumble of a kerosene heater, and a thermistor to be used for a fire alarm or a like.  
         [0053]    The power source managing section  302  being started to operate by the sensor  101  feeds power supply to the control circuit  201  and the data processing section  102  to produce measurement data by performing data processing including an A/D conversion of the electrical signal fed from the sensor  101 , accumulation of data, detection of a change in data, addition of information obtained from each kind of objects to be measured (such as temperatures), or a like. Further the power source managing section  302  has the transmitting unit  40  start so as to produce communication data as shown in FIG. 2 by communication data producing section  401  and transmits communication data from the communication section  402 .  
         [0054]    After transmitting communication data, the power source managing section  302  stops supply of power to the data processing section  102 , the control circuit  201 , and the transmitting unit  40  by receiving transmit completion signal from the transmitting unit  40 . That is, the transmitting unit  40  is operated intermittently as shown in FIG. 3. By operating the monitoring terminal device of the embodiment as above, currents required except when data is transmitted is standby current of only the sensor  101  and, therefore, power consumption is greatly reduced. The thermistor consumes power supply more or less because of being a resistance even during standby state. But the bimetallic thermometer, the lead switch, and the mercury switch consume no power supply at all when they are used setting the state of switch off into standby state, as a result, power consumption during standby can be zero perfectly.  
         [0055]    In the present invention since the transmitting unit  40 , only when a change in the physical quantity measured by the sensor unit  10  (as shown by the number “ 30 ” in FIG. 3) occurs, transmits communication data (as shown by the number “ 31 ” in FIG. 3), if the change is small, the transmitting unit  40  stops transmitting communication data for a long time, which serves to reduce current consumption accordingly, in other hand, makes difficult to judge the monitoring terminal device is operating normally or is out of commission. Therefore it is necessary to notify that the monitoring terminal device is operating normally, and for notifying it is desirable that a fault diagnosis signal (a signal as shown by the reference number “ 32 ” in FIG. 3) is transmitted in every specified period of time.  
         [0056]    Therefore, irrespective of the starting signal from the sensor  101  the control circuit  201  and the transmitting unit  40  are started by the starting signal from the timer  202  in a specified cycle so that the fault diagnosis signal is transmitted from the transmitting unit  40 .  
         [0057]    By setting the ratio (Operation duty=operating time/operating cycle) between the operating time and the operating cycle of the transmitting unit  40  at about  {fraction (1/1000)} to    {fraction (1/1000000)}, current consumption in the operation state can be reduced to a degree that it can be neglected when compared with current consumption in standby state. In the embodiment of the present invention, the operating time of the sensor unit 10 and the transmitting unit 40 are set at several ms meanwhile the operating cycle (transmitting cycle of the fault diagnosis signal) is set at several seconds to several minutes. It is needless to describe that the operating time and the operating cycle are properly selected depending on an object to be measured.    
         [0058]    Moreover, completion of data transmission by the transmitting unit  40  in a short time can be achieved by increasing a bit rate of communication data. For example, when data (about 80 bits) having a frame configuration as shown in FIG. 2, if the data is transmitted at 9.6 kbps, required operating time is 8.5 ms as shown in FIG. 4.  
         [0059]    In the monitoring terminal device of the embodiment of the present invention, while the state of standby, the power source managing section  302  stops feeding power supply to not only the data processing section  102  and the transmitting unit  40  (first stage sleep shown in FIG. 5) but also the power source managing section  302  itself and the control circuit  201  (second stage sleep shown in FIG. 5). That is, the standby power consumption becomes only the power consumption of the timer  202 , which outputs the starting signal to the power source managing section  302  every transmitting cycle of the fault diagnosis signal. Therefore standby currents required by the monitoring terminal device can be reduced to several tensμA (in the case of the embodiment of the invention it is 1.5 μA) which is same as standby currents of the control circuit  201 .  
         [0060]    Therefore, even in an indoor place where sunlight does not reach directly, the monitoring terminal device can be fully operated using a solar cell (amorphous-type solar cell of the embodiment of the present invention can supply 9 μA of output current and emit 200 lux of light for indoor brightness).  
       Second Embodiment  
       [0061]    [0061]FIG. 6 is a block diagram of a monitoring terminal device of a second embodiment of the present invention. In FIG. 6, same reference numbers are assigned to components having the same function as those in FIG. 1. In the second embodiment a delay circuit  203  is added to decide operation time of a control circuit  201 , a data processing section  102 , and a transmitting unit  40  other than the components shown in FIG. 1. The control circuit  201 , which is started with power supply from a power source managing section  302 , operates the data processing section  102  and the transmitting unit  40  during a specific period of time. The specific period of time is decided by a time constant of the delay circuit  203 , which is also started with power supply from the power source managing section  302 . As a matter of course data transmission must be reached completion within the above specific period of time.  
         [0062]    A mono stable multi vibrator (MMV) or a counter can be used as one example of the delay circuit  203 . Especially when communication data shown in FIG. 2 has a fixed-length, they work effectively.  
       Third Embodiment  
       [0063]    [0063]FIG. 7 is a block diagram of a monitoring terminal device according to a third embodiment of the present invention. In FIG. 7, same reference numbers are assigned to components having the same function as those in FIGS. 1 and 2. Referring to FIG. 7, a sensor unit  10  has two or more sensors  101 - 1  to  101 - n  (“n” is an integer being 2 or more), each of which monitors and measures a different physical quantity, and its data is transmitted from a transmitting unit  40 . In the third embodiment, as an example of each of the sensors  101 - 1  to  101 - n , a bimetallic thermometer for measurement of temperatures, a proximity perception sensor (lead switch) for detection of a closing or opening state of a window, or a mercury switch for detecting slope to be used for detecting tumble. Moreover, any sensor, so long as can start a power source managing section  302  with detecting state change (temperature change or a like) of object to be measured is not limited to sensors mentioned above. FIG. 8 is a diagram explaining each operations of the monitoring terminal device of the third embodiment of the present invention.  
         [0064]    By constructing the control unit  20 , the power source managing section  302 , the transmitting unit  40 , or the like using IC (Integrated Circuit) chips which can perform processes including the power source managing processing, the signal processing, and the frame construction processing in each above embodiments, it is made possible to standardize the monitoring terminal device of the present invention, which can provide advantages of easiness of design, reduction in manufacturing costs, or a like.  
         [0065]    It is apparent that the present invention is not limited to the above embodiments but may be changed and modified without departing from the scope and spirit of the invention.