JPH0651058A - Ultrasonic sensor with foreign matter sensing function - Google Patents

Abstract

PURPOSE:To provide an ultrasonic sensor having a foreign matter sensing function using ultrasonic waves with no risk of erroneous emission of an existence sensing signal even in case any person has gone out of the room with a stationary object left behind. CONSTITUTION:An ultrasonic' sensor concerned is so structured that sensing of movement is made alternately with the sensing of existence which is to store the wave reception data before and after the movement sensing in the first and the second memory circuit 17, 18 and to compare and that the contents of the second memory circuit 18 is transferred to the first memory circuit 17 when neither of the two sensing signals is obtained, wherein the arrangement includes a processing circuit 20 to transfer the content of the second memory circuit 18 when the movement sensing signal is obtained, a third memory circuit 19 to which the transfer is to be made, and a judging circuit 16 to transfer the contents of the third memory circuit 19 to the first memory circuit 17 when the wave reception data of the next existence sensing is equal to the contents of the third memory circuit 19.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultrasonic sensor that detects the movement and presence of an intruding object using ultrasonic waves.

[0002]

2. Description of the Related Art An ultrasonic pulse is transmitted from a transmitter to receive a reflected wave from an object existing in a surveillance area, and a frequency component generated in the reflected wave by the Doppler effect is detected to detect an intruding object. A movement detection method that detects movement and a method of transmitting ultrasonic pulses from a wave transmitter to receive reflected waves from an object and comparing the received data of reflected waves that have been sampled in time series. Therefore, an ultrasonic sensor that detects the movement of an intruding object and the presence of the intruding object is alternately put into practical use by alternately switching the presence detection method that detects the presence of an object in the surveillance area and the presence detection method at regular intervals. There is.

FIG. 3 shows an example of the configuration of such an ultrasonic sensor. The electric signal oscillated from the oscillator 1 is shaped into a tone burst wave by the wave transmission circuit 2, converted into an ultrasonic pulse from the ultrasonic wave transmitter 3, and output. This ultrasonic pulse is reflected by an object in the monitoring area, received by the ultrasonic receiver 4 and converted into an electric signal. This electric signal is sent to the amplifier circuit 11 by the wave-by-wave switching circuit 5, is amplified, and is detected by the detection circuit 14. The detected received wave data is stored in the second storage circuit 18, and then compared with the received wave data stored in advance in the first storage circuit 17 by the comparison circuit 15. This comparison result is sent to the detection / judgment circuit 12 as a match / mismatch,
The detection / judgment circuit 12 outputs a detection signal indicating that an intruding object is present when there is a mismatch, and stores it when there is a match.

When the time required for transmission / reception of the above-mentioned presence detection method has elapsed, a timer signal is output from the timer circuit 10 to the transmission method determination circuit 13, and the transmission method determination circuit 13 uses this as the movement detection method. To the wave transmission switching circuit 5 and the wave transmission circuit 2. In response to this, the wave transmission circuit 2 shapes the electric signal oscillated from the oscillator 1 into a continuous waveform of the movement detection system and sends it to the ultrasonic wave transmitter 3, which then transmits the ultrasonic wave to the ultrasonic wave transmitter 3. Converted to and transmitted. This ultrasonic wave is reflected by an object in the monitoring area, received by the ultrasonic wave receiver 4, and converted into an electric signal. This electric signal is sent to the amplifier circuit 6 by the wave-by-wave switching circuit 5, is amplified, and is mixed with the wave signal by the mixer 7. The Doppler signal included in the reflected wave signal is detected by the detection circuit 8, amplified by the amplification circuit 9, and input to the detection determination circuit 12. When the detection determination circuit 12 detects the Doppler signal, it determines that the object has moved, and outputs a movement detection signal.

When a predetermined time of the above movement detection method has elapsed, a timer signal is output from the timer circuit 10 to the transmission method determination circuit 13, and the transmission method determination circuit 13 switches the detection method to the presence detection method, Switching circuit for each wave 5
To the wave transmission circuit 2. Hereinafter, similarly, the presence detection method and the movement detection method are alternately repeated, and the detection signals of the both detection methods are appropriately related to each other to be used, for example, for lighting control of a toilet.

[0006] In the conventional toilet lighting control and the like, the detection signals of the presence detection method and the movement detection method are related as follows, for example. That is, when both detection signals are not output, the detection determination circuit 12 causes the first storage circuit 17 to
In response to an acceptance command to the second storage circuit 18, the stored contents are transferred from the second storage circuit 18 to the first storage circuit 17, and the received wave data as a reference for comparison is updated. When the movement detection signal is output, an acceptance command is not output from the detection determination circuit 12 to the first storage circuit 17, the transfer is stopped, and the received data immediately before the movement detection signal is output is compared. The standard of Thereafter, while either of the detection signals is being output, the acceptance instruction from the detection determination circuit 12 to the first storage circuit 17 is not output, and the above transfer is not performed. When both detection signals are no longer output, the detection determination circuit 1
An acceptance command is output from 2 to the first memory circuit 17,
The contents stored in the second memory circuit 18 are transferred to the first memory circuit 17.

The relationship between the presence detection signal and the movement detection signal as described above will be specifically described with reference to lighting control of a toilet. Since the movement detection signal is output when the door is opened, the received light data before the door is opened is compared with the reception data immediately before the movement detection signal is output while the lighting is turned on. Is used as the standard. Therefore, since the unattended state becomes the reference data for comparison, the presence detection signal continues to be output while the person is in the room, so the illumination is not turned off regardless of the output of the movement detection signal, The received data that is the basis for comparison is not updated. Then, after the person leaves the room, not only the movement detection signal but also the presence detection reception data becomes the same unattended state as the comparison reference data,
Since the presence detection signal is no longer output, the illumination is turned off.

However, in this case, if a person leaves an object in the room when the person leaves the room, the presence detection signal continues to be output, and the illumination cannot be turned off.

[0009]

DISCLOSURE OF THE INVENTION The present invention is proposed to solve the above problems, and does not erroneously output a presence detection signal even when a person leaves a stationary object indoors and leaves the room. An object is to provide an ultrasonic sensor having an object detection function.

[0010]

An ultrasonic sensor having an intruding object detecting function according to the present invention, which is proposed to achieve the above object, transmits an ultrasonic wave to a monitoring area and then transmits the ultrasonic wave to the inside of the monitoring area. It receives the reflected wave from the existing object, detects the frequency component generated in the reflected wave by the Doppler effect, detects the movement of the intruding object, and sends an ultrasonic pulse to detect the frequency from the object. The reflected wave is received, and the presence detection method for detecting the presence of an object in the surveillance area is alternately switched at regular time intervals by comparing the received data of the reflected wave sampled in advance in time series. The movement detection method detects the movement of an intruding object, and the reception data before and after the transmission and reception by the movement detection method is stored in the first and second storage circuits in time series,
When the stored contents of the first and second storage circuits are compared and they do not match, it is determined that the presence of an intruding object has been detected,
When the detection signals obtained by both the movement and presence detection methods are not obtained, when the movement detection signal is obtained in the ultrasonic sensor that transfers the storage content of the second storage circuit to the first storage circuit,
The processing circuit for transferring the storage content of the second storage circuit, the third storage circuit as the transfer destination, and the storage content of the second storage circuit storing the presence detection signal after the next presence detection method and The comparison determination circuit compares the storage contents of the three storage circuits, and the determination circuit transfers the storage contents of the third storage circuit to the first storage circuit when the comparison results are equal.

[0011]

In the ultrasonic sensor having the intruding object detection function according to the present invention, when the movement detection signal and the presence detection signal are not output, the received wave data, which is a reference for comparison of the presence detection methods, is repeatedly updated to detect the movement. When the signal is output, the reception data of the presence detection method immediately before and after that are compared, and when the two match, the reception data serving as a reference for comparison is updated with the matched reception data. Therefore, even when a person leaves a stationary object in the room and leaves the room, the received data of the presence detection method before and after the movement detection signal is output by the closing operation of the door becomes equal including the stationary object, and the comparison is made. Since the received wave data that is the reference of is updated, the presence detection signal is not output by the stationary object.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration example of an ultrasonic sensor according to the present invention. The configuration and operation of such an ultrasonic sensor will be described below. The individual operations of the movement detection method and the presence detection method and the operation of alternately repeating the detection are the same as those in the conventional example, and thus the description thereof will be omitted.

The following operation is performed according to the detection signals of the movement detection method and the presence detection method. When both detection signals are not output, the storage determination is performed from the second storage circuit 18 to the first storage circuit 17 by an acceptance command from the detection determination circuit 12 to the first storage circuit 17, and a reception reference serving as a reference is compared. Update wave data. When the movement detection signal is output, the acceptance instruction to the first storage circuit 17 is not output from the detection determination circuit 12, the transfer is stopped, and the processing instruction is output from the detection determination circuit 12 to the processing circuit 20. Then, the processing circuit 20 transfers the stored contents from the second memory circuit 18 to the third memory circuit 19. Then, when the received wave data by the presence detection method immediately after this is input to the second memory circuit 18, the comparison / determination circuit 21 compares the stored contents of the second memory circuit 18 and the third memory circuit 19 and they match each other. The determination circuit 16 transfers the stored contents from the third storage circuit 19 to the first storage circuit 17 when the above conditions are met, and the transfer is not performed when they do not match.

Thereafter, while either of the detection signals is being output, the acceptance command from the detection determination circuit 12 to the first memory circuit 17 is not output, and the second memory circuit 18 outputs the first command.
The storage contents are not transferred to the storage circuit 17. Also,
When the movement detection signal is output and the reception data before and after the presence detection match, the reception data, which is the reference for comparison in the first memory circuit 17, is updated by this reception data.

When both detection signals are no longer output, the detection judgment circuit 12 outputs an acceptance command to the first storage circuit 17, and the storage content of the second storage circuit 18 becomes first.
The data is transferred to the memory circuit 17. When the above operation is applied to the case of lighting control of the toilet, the movement detection signal is output when the door is opened, so that the lighting is turned on and the unmanned wave reception before the door is opened The data serves as the basis for comparison of presence detection. Since the reception data of the presence detection before and after the movement detection signal do not match, the reception data of the unmanned state is not updated by the reception data of the presence detection after the movement detection signal,
It is left as a reference for presence detection comparison.

While a person is closing the door and moving indoors,
Since the frequency component due to the Doppler effect is detected, the movement detection signal is output and the illumination is not turned off. Further, since the reception data of the presence detection before and after the movement detection signal do not match, the reception data of the unmanned state is not updated by the reception data of the presence detection after the movement detection signal. Even when a person is sitting and standing still, even if the movement detection signal is not output, the unmanned wave reception data described above serves as a reference for presence detection comparison. Since they are different, the presence detection signal continues to be output and the illumination is not turned off.

When a person leaves the room and closes the door, the last movement detection signal is output.
A person has exited the door and is not in the presence detection area,
It matches the reception data of the presence detection immediately after the last movement detection signal. Therefore, the wave reception data in a state where the person has exited the door and is not in the presence detection area is updated as the wave reception data serving as a reference for comparison. As a result, even if the stationary object remains in the presence detection area, the stationary object is also included in the received data that is the reference for the subsequent comparison, so that the presence detection signal is not output and the illumination is turned off. 2 (a)-
(G) is a bird's-eye view of such a situation.

[0018]

According to the ultrasonic sensor having the function of detecting an intruding object according to the present invention, when the movement detection signal and the presence detection signal are not output, it is possible to update the reception data which is a reference for comparison of the presence detection methods. When the movement detection signal is repeatedly output, the reception data of the presence detection method immediately before and immediately after that are compared, and when the two match, the reception data that is the reference for comparison is based on this matched reception data. To update. Therefore,
Even if a person leaves a stationary object in the room and leaves the room, the received data of the presence detection method before and after the movement detection signal is output due to the closing motion of the door is equal including the stationary object, and the comparison criteria Since the received wave data is updated, the presence detection signal is not output by the stationary object. As a result, the lighting in the room is turned off correctly.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an ultrasonic sensor having a function of detecting an intruding object according to the present invention.

FIG. 2 is a bird's-eye view for explaining a situation when an ultrasonic sensor having a function of detecting an intruding object according to the present invention is used for lighting control of a toilet.

FIG. 3 is a diagram showing a configuration example of an ultrasonic sensor having a conventional intruding object detection function.

[Explanation of symbols]

 3 ... Ultrasonic wave transmitter 4 ... Ultrasonic wave receiver 12 ... Detection judgment circuit 15 ... Comparison circuit 16 ... Judgment circuit 17 ... First memory circuit 18 ... 2 memory circuit 19 ... 3rd memory circuit 20 ... processing circuit 21 ... comparison judgment circuit

Claims (1)

[Claims] 1. An ultrasonic wave is transmitted to a surveillance area, a reflected wave from an object existing in the surveillance area is received, and a frequency component generated in the reflected wave by the Doppler effect is detected to detect an intruding object. The movement detection method that detects movement and the ultrasonic wave are transmitted, the reflected wave from the object is received, and the received data of the reflected wave that is sampled in advance is compared in time series to obtain a monitoring area. The presence detection method, which detects the presence of objects inside, is alternately switched at regular intervals, the movement detection method detects movement of an intruding object, and the movement detection method receives and transmits signals before and after the wave detection. Wave data is stored in the first and second storage circuits in time series, and the stored contents of the first and second storage circuits are compared and if they do not match, it is determined that the presence of an intruding object is detected, Both movement and existence inspection When not obtain a detection signal according to the method is
In the ultrasonic sensor that transfers the storage content of the second storage circuit to the first storage circuit, when the movement detection signal is obtained,
After the processing circuit that transfers the storage contents of the storage circuit, the third storage circuit that is the transfer destination, and the next presence detection method,
A comparison / determination circuit that compares the stored content of the second storage circuit and the stored content of the third storage circuit, which stores the received wave data of the presence detection, and when the comparison result is equal, the stored content of the third storage circuit is set to the first storage content. An ultrasonic sensor having a function of detecting an intruding object, which is provided with a determination circuit for transferring to a storage circuit.