JPH0245240B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a wireless sensor device used in home security systems and the like.

[Prior Art] FIG. 1 is a schematic diagram showing a home security system using a conventional wireless sensor device, and FIG. 2 is a configuration diagram showing the conventional wireless sensor device. In the figure, 1, 2, and 3 are wireless sensor devices that detect abnormalities such as fire, gas leak, intrusion, etc., respectively. For example, 1 is fire, 2 is gas leak, and 3 is intrusion. Depending on the type of sensor (fire, gas leak, intrusion, etc.) and state (occurrence of an abnormality, release), a packet containing a code signal corresponding to the sensor is sent out using infrared rays, radio waves, etc. 4 is a receiver that receives packets from each of the sensor devices 1, 2, and 3; 5 is a controller that decodes and processes the received packets; and 6 is a display that displays abnormalities detected by the sensor devices 1, 2, and 3. It is a vessel. In Fig. 2, 7 is a sensor shown as an equivalent circuit as a switch, 8 is a code switch that sets a code corresponding to the type of sensor, 9 is a DC current terminal, 10 is a microcomputer (hereinafter referred to as microcomputer), and 11 is a transistor, 12
is a light emitting diode (hereinafter referred to as LED).

Next, its operation will be explained. The contacts of the sensor 7 are open under normal conditions, but close when an abnormality occurs. The closing signal of the contact of this sensor 7 is input to the input terminal 11 of the microcomputer 10, and the code data set by the code switch 8 and input to the input terminals 2 to 5 determines the type of abnormality and its occurrence. A digital data packet indicating this is created and output as a serial digital signal from output terminal O1. This signal turns on and off the transistor 11, causes the LED 12 to blink, and data indicating the occurrence of an abnormality is sent into space as an infrared packet signal. This signal is received by a receiver 4 and decoded by a controller 5,
It is displayed on the display 6.

The conventional wireless sensor is configured as described above, and each sensor includes a microcomputer 10, an LED 12, and a battery that supplies power to these via a terminal 9. Therefore, abnormality detection by the sensor 7,
That is, if the contacts are closed continuously, the battery will be consumed more and the battery will have to be replaced more frequently.

[Summary of the Invention] This invention was made to eliminate the drawbacks of the conventional ones as described above, and detects the change of the sensor from open to closed and from closed to open. After turning on the power to the circuit that controls the transmission of packets and sending out the packets notifying the above abnormality a predetermined number of times, the power is automatically turned off again.
It is an object of the present invention to provide a wireless sensor device that can reduce battery consumption by turning on a power supply circuit only when a sensor output signal changes, such as when an abnormality occurs or is cleared.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram showing an embodiment of the present invention. In the figure, 7 to 12 are the same as in FIG. 2, and 13 is a circuit for detecting a change in the signal of the sensor 7. 14 is a Schmitts trigger circuit that shapes the output of the sensor 7, and when there is no detection signal between the contacts of the sensor 7, the ground potential level (hereinafter referred to as L) is set to
By closing the contact of the sensor 7, a control power supply potential level (hereinafter referred to as H) is output. 15, the input is L
Inverter that outputs H when , and L when H, 1
6, 17, 18 have 2 inputs IN1 and IN2 both high.
NAND that outputs L only when , and H at other times,
19 is a delay circuit consisting of a resistor 20 and a capacitor 21, and 22 is a delay circuit consisting of a resistor 23 and a capacitor 24. 25 is H to the set input terminal S.
A flip-flop which is set by applying a pulse to output an H signal and which is reset by applying an H pulse to a reset input terminal R and outputs an L signal from an output terminal O; 26 is a switching transistor inserted in the power supply circuit of the microcomputer 10; 27 is an inverter that converts the L pulse output from the output terminal O2 of the microcomputer 10 into an H pulse output.

Next, the operation will be explained with reference to the waveform diagram of each part in FIG. The contact point of the sensor 7, which was in the open state, closes due to the abnormality detection, and the output signal 28 is changed to the time point t.
1 from H to L, the output of the Schmitts trigger circuit 14 of the change detection circuit 13 changes from L to H, and therefore
Input IN129 of NAND16 is inverted by inverter 15 and goes from H to L, input IN1 of NAND17
32 changes from L to H. However, NAND1
6, 17 inputs IN2 30, 33 are delay circuits 19,
22, and at time t2, they change from L to H and from H to L, respectively. Therefore, only the output 34 of the NAND 17 whose both inputs are H becomes L between t1 and t2, during which time H is applied from the NAND 18 to the set terminal S of the flip-flop 25, the flip-flop 25 is set, and its output 37 becomes H. This output 37 makes the transistor 26 conductive, and power is supplied to the microcomputer 10 from the power supply terminal 9. Therefore, the microcomputer 10 creates a packet of code signals indicating the type of abnormality and its occurrence in response to the signal from the sensor 7 to the input terminal 11 and the signal from the code switch 8 to the input terminals 12 to 15. Output to the base of transistor 11. The signal 38 amplified by the transistor 11 causes the LED 12 to turn off and emit an infrared signal, which is sent into space. The number of times this packet is transmitted is counted by the microcomputer 10, and when it reaches a predetermined number, an L pulse is output to the output terminal O2 at time t3, which is converted to an H pulse 36 by the inverter 27, and the flip-flop 25 is reset. The output 37 is set to L, the transistor 26 is turned off, and the microcomputer 1 is reset.
Cut off power supply to 0. As a result, there is no output to the transistor 11, and the transmission of the infrared signal is stopped.

Next, the abnormality is canceled and the contact point of the sensor 7 changes at time t.
When it is opened at t5, the input IN129 of NAND16 becomes H, and after a slight delay, its input IN230 becomes high at t5.
becomes L and both inputs become H, an L pulse 31 is output during a period t4 to t5, and an H pulse 35 is output from the NAND 18 and applied to the set terminal S of the flip-flop 25 to set it. Therefore, the transistor 26 becomes conductive, and power is supplied to the microcomputer 10 again. Here, the microcomputer 10 creates a packet of a code signal indicating the type of abnormality and that it has been cleared, drives the transistor 11, and sends it out into space as an infrared signal from the LED 12. After transmitting the packet a predetermined number of times, The reset signal 36 is output again and the power is cut off.

FIG. 5 is a flowchart showing the flow of the control operation of the microcomputer 10. When the transistor 26 becomes conductive and power is supplied to the microcomputer 10, first, in step 39, the code switch 8 is connected to the input terminal t.
Sensor type codes from 2 to t5 are input. Next, in step 40, a signal indicating the occurrence or cancellation of an abnormality is read from the sensor 7 to the input terminal I1, and the word structure of the data to be transmitted is determined by the processing in steps 39 and 40. Furthermore, in step 41, a transmission count counter is set to an initial value.
For example, if you set the number of transmissions to 5, the microcomputer 10
It is assumed that transmission is completed after five transmissions. Next, in step 42, a packet of the transmission word determined in steps 39 and 40 is transmitted. When one transmission is completed, the process advances to step 43, where the transmission count counter is decremented by 1, and in step 44, it is checked whether the counter has reached 0. If it has not become 0, the process returns to step 42, and the counter is Transmission is repeated until the number becomes 0. Here, a predetermined number of times, for example, 5
When the transmission is completed, 0 is detected in step 44, and
Proceeding to step 45, an L pulse to turn off the power is output to the terminal O2, the power is disconnected, and the transmission ends.

FIG. 6 shows the structure of a transmitted packet. One pulse 46 in C of the same figure is a packet transmitted once, and as described above, it is transmitted, for example, five times. Part 1
The packet 45 consists of a pulse train of a word structure representing 1 and 0 at pulse intervals as shown in FIG. It is. With such a configuration, it is possible to remove disturbance noise with a bandpass filter in the receiver, and the duty is low, so power consumption during transmission is low.

In the above embodiment, an example was shown in which an infrared signal was used as the signal, but radio waves or ultrasonic waves may also be used.

[Effects of the Invention] As described above, the present invention is configured to automatically disconnect the power supply after sending packets a predetermined number of times only when the state of the sensor changes, reducing power consumption and making it easier to replace batteries. This has the effect of reducing the number of times. Furthermore, when the abnormality detection times of a plurality of wireless sensors overlap, there is also an advantage that the probability that the transmission signals are transmitted simultaneously is reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a home security system using a conventional wireless sensor device, FIG. 2 is a configuration diagram showing a conventional wireless sensor device, and FIG. 3 is a configuration diagram showing an embodiment of the present invention. , FIG. 4 is a waveform diagram of each part for explaining its operation, FIG. 5 is a flowchart showing the operation of the microcomputer used in this embodiment, and FIG. 6 is a configuration diagram of its transmission packet. In the figure, 7 is a sensor, 8 is a code switch that sets the sensor type, 10 is a microcomputer that is a circuit that controls packet transmission, and 1
1 is a transistor for amplifying a transmission signal; 12 is a light emitting diode for transmitting light; and 13 is a circuit for detecting a change in the output signal of the sensor 7. 25 is a flip-flop,
Reference numeral 26 denotes a transistor, which constitutes a means for turning on the power based on a change in the sensor output. Reference numeral 27 denotes an inverter, which together with the flip-flop 25, the transistor 26, and the program of the microcomputer 10 constitutes means for disconnecting the power supply by transmitting a packet a predetermined number of times. Identical parts in the drawings indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A wireless sensor that detects the output signal of a sensor and intermittently and repeatedly transmits a packet containing a code signal corresponding to the type and state of the sensor using light, radio waves, or ultrasonic waves. In the apparatus, means for detecting a change in the output signal of the sensor; and means for turning on a circuit for controlling the transmission of the packet by detecting the change in the sensor output signal by the means; A wireless sensor device characterized by comprising means for disconnecting the power source of the circuit that controls the transmission of the packets. 2. The wireless sensor device according to claim 1, wherein the sensor is a sensor for detecting an abnormality, and the means for detecting a change in the output signal of the sensor is means for detecting the occurrence of an abnormality and the detection of cancellation of an abnormality of the sensor. .