JP2012123714A - Wireless sensor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent shortening of battery life and also to make the time required for modes of all slave units to switch from a non-warning mode to a warning mode shorter than the time required for modes of all the slave units to switch from a warning mode to a non-warning mode.SOLUTION: Since an intermittent reception period T2 of each slave unit Si in a warning mode is set longer than the intermittent reception period T1 in a non-warning mode, a transmission period to transmit a wireless signal including a control command from a transmitting-receiving part 12 of a master unit M is changed to a time length corresponding to the intermittent reception period T2. Therefore, with respect to the time to process mode switching, that is, the time required for a display part 14 of the master unit M to display a switched mode after a switch for mode switching is operated, the time for switching from a non-warning mode to a warning mode becomes shorter than the time for switching from a warning mode to a non-warning mode.

Description

  The present invention relates to a wireless sensor system.

  An example of a conventional wireless sensor system is described in Patent Document 1. The wireless sensor system described in Patent Document 1 includes a plurality of security sensors (slave devices) and one communication device (master device). Each slave unit has a sensor for detecting opening / closing of a window, the presence of a person, etc., and a wireless communication means for transmitting a detection result by the sensor to the master unit and receiving a mode switching control command transmitted from the master unit. have. Further, the parent device performs wireless communication with the child device, receives a detection result transmitted from the child device, issues an alarm, or switches the child device between a warning mode and a non-warning mode. However, the alert mode is a mode in which the slave unit validates a function (sensor function) for transmitting the detection result of the sensor to the master unit, and the non-alert mode is a mode in which the sensor function is invalidated. In addition, these cordless handsets are configured to operate using a battery as a power source in order to take advantage of the wireless communication that wiring is unnecessary and construction work is easy. In order to extend the life of the battery, each slave unit performs an intermittent reception operation of starting the reception circuit at every predetermined intermittent reception cycle and immediately stopping the reception circuit if no radio signal is received.

  In this conventional example, an operation when a control command is transmitted from the parent device and each child device is switched from the non-warning mode to the warning mode will be briefly described. The master unit multicasts (broadcasts) a mode switching control command with a transmission time longer than the intermittent reception cycle of the slave unit. Each slave unit switches from intermittent reception to constant reception when receiving a multicast control command from the master unit. After multicasting the control command, the master unit unicasts the mode switching control command again to any one slave unit with a transmission time sufficiently shorter than the intermittent reception cycle. Since the slave unit always receives the multicast control command previously received, it can receive the control command unicast from the master unit for a short time. The slave unit that has received the control command switches from the non-alert mode to the alert mode, and returns (unicast) a reception response (ACK) to the master unit. When receiving the reception response from the slave unit, the master unit unicasts a mode switching control command to another slave unit. In this way, the parent device sequentially unicasts the control commands to all the child devices, so that all the child devices can be surely switched to the alert mode. Further, by receiving a reception response returned from each slave unit, the master unit can confirm that each slave unit has been switched from the non-warning mode to the warning mode. The master unit notifies (displays) when all the slave units are switched from the non-warning mode to the warning mode or from the warning mode to the non-warning mode.

JP 2005-108071 A

  By the way, when the above-described wireless sensor system is installed in a house, a store, an office, or the like, the slave unit is switched from the warning mode to the non-warning mode when the resident returns home or the employee goes to work. On the other hand, when the resident goes out or the employee leaves the office, the handset is switched from the non-warning mode to the warning mode. At this time, when switching from the non-warning mode to the warning mode (when going out or leaving work) rather than when switching from the warning mode to the non-warning mode (when returning home or going to work), the mode change notification by the parent machine is issued. It is desirable to do it early. This is because switching from the non-warning mode to the warning mode is performed when the resident goes out or when the employee leaves the office, so it is considered that the resident or the employee is rushing out or leaving the office.

  However, in the conventional example described in Patent Document 1, since the intermittent reception cycle of each slave unit is not synchronized, the mode switching control command must be multicast one or more times in a transmission time longer than the intermittent reception cycle. Don't be. As a result, it takes a considerable time for all the slave units to switch from the non-warning mode to the alert mode and be notified by the master unit. If the intermittent reception cycle of each slave unit is shortened, it is possible to shorten the time until all slave units are switched from the non-warning mode to the alert mode and notified by the master unit. However, if the intermittent reception cycle is shortened in order to shorten the time required for mode switching, the battery life is also shortened.

  The present invention has been made in view of the above problems, and while suppressing the shortening of the battery life, the time until all the slave units are switched from the non-warning mode to the alert mode, all the slave units are in the alert mode. The purpose is to shorten the time from switching to non-warning mode.

  The wireless sensor system of the present invention includes a master unit and a plurality of slave units having a sensor function. The slave unit waits for reception of a radio signal at a predetermined intermittent reception cycle, and from the master unit. When a transmitted mode switching control command is received, the alarm mode for enabling the sensor function and the non-warning mode for disabling the sensor function are selectively switched, and the intermittent operation in the non-warning mode is performed. The intermittent reception period in the alert mode is set to be longer than the reception period.

  In this wireless sensor system, it is preferable that the slave unit starts counting the intermittent reception cycle when a predetermined time has elapsed from the completion of reception of the mode switching control command.

  The wireless sensor system of the present invention switches the time until all the slave units are switched from the non-warning mode to the warning mode while suppressing the shortening of the battery life, and all the slave units are switched from the warning mode to the non-warning mode. There is an effect that it can be shortened than the time until.

It is a time chart for demonstrating the operation | movement at the time of mode switching of the subunit | mobile_unit in embodiment. It is a block diagram of the main unit and the sub unit in the embodiment. It is a frame format of a radio signal in an embodiment. It is a time chart for demonstrating another operation | movement at the time of mode switching of the subunit | mobile_unit in embodiment.

  As shown in FIG. 2, the wireless sensor system of the present embodiment includes one master unit M and a plurality of slave units Si (i = 1, 2, 3,...) In the illustrated example. It is configured.

  The slave unit Si includes a slave unit control unit 20, an antenna 21, a slave unit transmission / reception unit 22, a sensor unit 23, and a battery power source unit 24. The slave transmission / reception unit 22 transmits / receives a radio signal using a radio wave as a medium in accordance with, for example, “radio station of low power security system” defined in Article 6, Paragraph 4, Item 3 of the Radio Law Enforcement Regulations. The sensor unit 23 detects the presence or amount of an object and converts it into an electrical signal. For example, the sensor unit 23 is added to a human sensor or a window glass that detects infrared rays emitted from a human body by a pyroelectric element. There are destruction sensors that detect vibration, and fire sensors that detect smoke and heat associated with fire. The slave unit control unit 20 includes a microcontroller (hereinafter abbreviated as a microcomputer) as a main component, and receives a radio signal including a message indicating a detection result of the sensor unit 23 (for example, intrusion of a suspicious person or fire). Processing to be transmitted from the machine transmitting / receiving unit 22 is performed. The battery power supply unit 24 creates and supplies operation power for the slave unit control unit 20, the slave unit transmission / reception unit 22, and the sensor unit 23 using a primary battery or a secondary battery as a power source. In order to prevent battery consumption as much as possible, these slave units Si perform a reception operation intermittently instead of constantly as described later.

  Base unit M includes base unit control unit 10, antenna 11, base unit transmission / reception unit 12, operation input reception unit 13, display unit 14, and power supply unit 15. For example, in the same way as the slave transmitter / receiver 22, the master transmitter / receiver 12 transmits radio waves in accordance with the “radio station of low power security system” defined in Article 6, Paragraph 4, Item 3 of the Radio Law Enforcement Regulations. Transmits and receives radio signals as a medium. The operation input receiving unit 13 includes one or more switches (for example, push button switches), and receives an operation input corresponding to each switch when the switch is operated, and receives an operation signal corresponding to the operation input. To the machine control unit 10. The base unit control unit 10 has a microcomputer as a main component in the same manner as the base unit control unit 20, and processing according to a detection result transmitted as a radio signal from any of the sub unit Si as described later, for example, intrusion of a suspicious person An alarm such as a fire or an alarm is notified by an alarm sound or an alarm display, or a process of notifying the occurrence of an abnormality to a remote report destination via some external communication means is performed. The display unit 14 is composed of a light emitting element such as a light emitting diode. Displays the mode switching status. The power supply unit 15 converts AC power supplied from an external power supply (for example, the commercial AC power supply 100) into DC power and supplies the DC power to the parent device control unit 10, the parent device transmission / reception unit 12, and the display unit 14. Since the base unit M operates from an external power supply, the base unit transceiver unit 12 is always in a waiting state for reception except during transmission (see FIG. 1), unlike the base unit Si.

  A unique identification code is assigned to each of the parent device M and the child device Si and stored in the memory of each of the control units 10 and 20, and the transmission destination and transmission source of the radio signal can be specified by the identification code. .

  FIG. 3 shows a frame format of a radio signal transmitted and received by the wireless sensor system of this embodiment. That is, one frame includes a synchronization bit (preamble), a frame synchronization pattern (unique word), a transmission destination address, a transmission source address, data (message), and a CRC code. Here, if an identification code is set as the transmission destination address, only the terminal (master device M, slave device Si) to which the identification code is assigned receives the radio signal and acquires the message. However, when a special bit string (for example, a bit string in which all bits are set to 1) that is not assigned to any terminal is set as a destination address, the radio signal is broadcast (multicast) and all terminals Get the message. For example, a radio signal including a mode switching control command is broadcast from the master unit M to all the slave units Si.

  By the way, in each handset Si, as described above, in order to make the battery life of the battery power supply unit 24 as long as possible, intermittent reception is performed except when a radio signal is transmitted. That is, the slave unit control unit 20 repeatedly counts a predetermined intermittent reception cycle with a timer built in the microcomputer, and activates the slave unit transmission / reception unit 22 every time the intermittent reception cycle count is completed, so that a desired radio wave (master unit) It is checked whether or not the wireless signal transmitted by M can be received. And if the said radio wave is not caught, the subunit | mobile_unit control part 20 will stop the subunit | mobile_unit transmission / reception part 22 immediately, and will transfer to a standby state, and is reducing the average power consumption significantly. The radio wave reception check is performed based on a received signal strength indication signal (Receiving Signal Strength Indication: RSSI signal) that is a DC voltage signal output from the slave unit transceiver unit 22 and proportional to the magnitude of the received signal strength. This is performed by the control unit 20.

  In addition, the slave unit controller 20 of each slave unit Si has an operation mode (warning mode) in which the detection result of the sensor unit 23 (detection of the presence of a person, detection of breakage of a window glass, etc.) is transmitted to the master unit M by radio signal In addition, the operation mode (non-warning mode) in which the detection result of the sensor unit 23 is not transmitted to the parent device M by radio signal can be selected alternatively, and the warning is based on an instruction (control command) from the parent device M. Switching between mode and non-warning mode. For example, when there is a person (resident or employee) in the target area (house, store, office, factory, etc.), each handset Si is set to non-warning mode, and each child when there is no person in the target area. Machine Si is set to the alert mode. In the non-warning mode, the slave unit control unit 20 stops the sensor unit 23 or does not transmit a wireless signal including the detection result while operating the sensor unit 23.

  The operation input receiving unit 13 of the base unit M is provided with a mode switching switch. When the switch is operated, the operation input receiving unit 13 receives a mode switching operation input and corresponds to the operation input. An operation signal is output from the operation input receiving unit 13 to the parent device control unit 10. When a mode switching operation signal is input, base unit control unit 10 generates a control command for switching each slave unit Si to a warning mode or a non-warning mode, and includes the control command and multicasts to a destination address The base station transmitting / receiving unit 12 transmits a radio signal in which an address (bit string) is set.

  When the radio signal is received by each slave unit Si, the slave unit control unit 20 switches between a warning mode and a non-warning mode based on a control command included in the radio signal. Further, the slave unit control unit 20 generates a response message (ACK message) to the control command, and transmits a radio signal including the response message and having the identification code of the base unit M set as the transmission destination address from the slave unit transmission / reception unit 22 Let

  When the base unit control unit 10 of the base unit M receives a response message indicating that the mode switching has been normally performed from all the handset Si, the mode switching process is displayed on the display unit 14 by displaying the mode switching state. Exit.

  In the handset controller 20, the intermittent reception cycle T2 in the warning mode is set to a longer time (T1 <T2) than the intermittent reception cycle T1 in the non-warning mode.

  Next, referring to the time chart shown in FIG. 1, the transmission / reception operation of this embodiment at the time of mode switching will be described in more detail.

  For example, it is assumed that a mode switching switch is operated in the parent device M when each child device Si is operating in the non-warning mode (see “▽” in FIG. 1). When the mode switching operation signal is input from the operation input receiving unit 13 as described above, the base unit control unit 10 generates a control command for switching each slave unit Si from the non-warning mode to the warning mode, and A radio signal including a command and having a multicast address (bit string) set as a transmission destination address is transmitted from the base transceiver unit 12. At this time, the base unit control unit 10 continuously transmits (continuous transmission) the radio signal within a period (transmission period) TS that is approximately the same as the intermittent reception cycle T1 of the slave unit Si, and after the continuous transmission period TS has elapsed. Switch base transceiver unit 12 to reception state. However, it is desirable that the transmission period TS is as short as possible even if the transmission period TS is equal to or longer than the intermittent reception cycle T1 of the slave unit Si.

  On the other hand, in each slave unit Si, the slave unit transmission / reception unit 22 receives a radio signal in synchronization with the intermittent reception timing, and a message (control command) included in the radio signal is passed to the slave unit control unit 20. Then, the slave unit control unit 20 switches from the non-warning mode to the warning mode based on the control command received from the parent device M. Further, the slave unit control unit 20 generates a response message for the control command, and causes the slave unit transmission / reception unit 22 to transmit a radio signal including the response message and having the identification code of the master unit M set as the transmission destination address. However, the slave unit control unit 20 of each slave unit Si receives a response message when a standby time specific to each slave unit Si has elapsed from the completion of reception of the wireless signal including the control command (end point of the transmission period TS). Is transmitted from the slave transmission / reception unit 22 to avoid a collision.

  Furthermore, after the slave unit control unit 20 switches from the non-warning mode to the warning mode according to the control command from the parent device M, the intermittent reception cycle is changed from the intermittent reception cycle T1 in the non-warning mode to the intermittent reception cycle T2 in the warning mode. Change to (> T1). Therefore, in the alert mode, the slave unit control unit 20 activates the slave unit transmission / reception unit 22 to perform intermittent reception at the intermittent reception cycle T2.

  The radio signal transmitted from the slave unit Si is received by the master unit M. In base unit M, base unit transmission / reception unit 12 receives the radio signal, and a response message included in the radio signal is passed to base unit control unit 10. Then, when receiving the response message from all the child devices Si, the parent device control unit 10 notifies that the non-warning mode has been switched to the warning mode by switching the display on the display unit 14.

  On the other hand, switching from the warning mode to the non-warning mode is performed in the same procedure. Here, since the intermittent reception cycle T2 of each slave unit Si is set to be longer than the intermittent reception cycle T1 of the non-warning mode in the warning mode, a radio signal including a control command is transmitted from the parent device transmission / reception unit 12. The transmission period is also changed to a time length corresponding to the intermittent reception cycle T2. Therefore, the processing time for mode switching, that is, the time required from when the mode switching switch is operated until the mode after switching is displayed on the display unit 14 of the main unit M is changed from the warning mode to the non-warning mode. When switching from the non-warning mode to the warning mode is shorter than when switching. Moreover, since the intermittent reception cycle T2 in the warning mode is set to be longer than the intermittent reception cycle T1 in the non-warning mode, the battery of each slave unit Si is compared with the case where the intermittent reception cycle is simply shortened. Consumption can be reduced, and shortening of battery life can be suppressed.

  As described above, in the wireless sensor system of the present embodiment, the time until all the slave units Si are switched from the non-warning mode to the warning mode while suppressing the shortening of the battery life, all the slave units Si are in the warning mode. It can be shorter than the time from switching to non-warning mode. As a result, it is possible to shorten the waiting time of residents who are going out and employees who are going to leave the office, thereby improving the usability of the wireless sensor system.

  By the way, as shown in FIG. 4, if the slave unit control unit 20 starts counting the intermittent reception cycles T1 and T2 when a certain time TX has elapsed since the completion of reception of the mode switching control command, all the slave units are started. The intermittent reception periods T1 and T2 in Si can be synchronized. Here, base unit control unit 10 also starts counting intermittent reception cycles T1 and T2 when a predetermined time TX has elapsed since the completion of reception of the mode switching control command. Therefore, base unit control unit 10 can transmit a radio signal including a control command from base unit transmission / reception unit 12 in synchronization with intermittent reception cycles T1 and T2. As a result, all the handset Si can receive a radio signal in a very short transmission time, and the waiting time of residents and employees can be further shortened when the mode is switched.

M parent machine
Si cordless handset
T1 Intermittent reception cycle in non-warning mode
Intermittent reception cycle in T2 warning mode

Claims (2)

  It has a master unit and a plurality of slave units having a sensor function. The slave unit waits for reception of a radio signal at a predetermined intermittent reception cycle, and sends a mode switching control command transmitted from the master unit. When received, selectively switch between a warning mode that enables the sensor function and a non-warning mode that disables the sensor function, and in the warning mode than the intermittent reception period in the non-warning mode A wireless sensor system in which the intermittent reception cycle is set to a longer time.   2. The wireless sensor system according to claim 1, wherein the slave unit starts counting the intermittent reception period when a predetermined time has elapsed from completion of reception of the mode switching control command.

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