JPS61170682A - Sound source searcher - Google Patents

Abstract

PURPOSE:To instruct quickly the direction of a sound source or approach the sound source by moving a sound source searcher toward the sound source without changing the direction to the right or left when the sound source is relatively remote and changing the direction when the sound source is nearby. CONSTITUTION:Only the signal corresponding to the acoustic wave signal which is faster in time is outputted when the time difference between the acoustic wave signals from a sound source X outputted from respective acoustic wave signal receiving means 1a, 1b is of the specified value or above. The signal corresponding to both acoustic wave signals is outputted when the time difference is smaller than the specified vale. Driving wheels 2a, 2b are driven by such output so that the searcher moves toward the sound source without shifting to the right or left when the sound source is relatively remote and the direction thereof is changed when the sound source is nearby. The quick instruction of the direction of the sound source and the approach to the sound source are thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sound source search device that receives sound waves emitted from a sound source that generates audible sounds or ultrasonic waves and searches for the direction of the sound source.

[Prior Art] Relatively simple sound wave detection devices are used in running objects such as toy cars that start, stop, etc. in response to specific sounds. The conventional sound wave detection function was to simply control the running, stopping, etc. of the vehicle using sound waves, regardless of the position or direction of the sound wave.In addition to this conventional sound wave detection function, it is necessary to detect from which direction the sound wave is coming from. A sound source search device has been proposed that can detect in which direction the sound source is located using a simple circuit configuration, and can move a running object toward the sound source, for example, and a patent application has been filed by the present applicant (Japanese Patent Application No. -1
17088), the principle of this device is as follows.

As shown in FIG. 1, a sound wave receiving means 1 such as a microphone receives sound waves emitted from a sound source X and converts them into electrical signals.
A and lb are arranged with a predetermined distance d left and right. now,
If the distances from the sound source X to the sound wave receiving means 1a and lb are respectively x a and x b, and the sound source first, and then the other sound wave receiving means 1b.

The arrival time difference in this case is the speed of the sound wave, which is 340Il/S
Then, Δt = (xb - xa) /340 [sec]
For example, the distance d between the two sound wave receivers 1a and 15 is 5 cm, the distance from the sound source X to the straight line connecting the two sound wave receivers is 2 m, and the distance from the center of the two sound wave receivers to the sound source When the deviation angle θ=300, xb −x
Since a = approximately 25 mm, the difference in arrival time of the sound waves to the sound wave receiving means is Δt = approximately 73.5 3 ec.

That is, since the sound wave receiving means la closer to the sound source X outputs a signal earlier by Δt, by using this output, it is possible to indicate the direction of the sound source or move the traveling object in that direction.

Particularly in the latter case, by driving the drive wheel 2b on the side opposite to the sound source X for a certain period of time among the left and right drive wheels 2a and 2b of the traveling body 3 equipped with a sound wave receiving means as shown in the figure, the traveling body 3 changes direction by a certain angle toward the sound source. Therefore, each time the traveling body 3 receives a sound wave, it changes its direction and gradually approaches the sound source.

[Problem to be solved by the invention 1 According to the sound source search device as described above, when the sound source X and the sound wave receiving means 1a and lb are completely equidistant (xa =
In xb), the traveling object moves straight towards the sound source, but in reality, the exact distance between them only occurs instantaneously, and even if they become equal distances, the traveling object moves straight toward the sound source due to vibrations, etc. It deviates from the distance position and almost never moves straight. As a result, the traveling body always moves with its tip end swinging from side to side. Although this may be interesting as a toy, it is not sufficient as a device to quickly and smoothly move towards the sound source because the speed of movement towards the sound source is slow.

The present invention has been made in view of the above, and its purpose is to move toward the sound source without changing direction to the left or right when the sound source is relatively far away, and quickly change direction when the sound source is close to the sound source. To provide a sound source search device capable of instructing the direction of a sound source and approaching the sound source.

[Means for solving the problem] The present invention arranges sound wave receiving means for converting sound waves into electrical signals at predetermined intervals, and detects the sound source depending on which sound wave receiving means the sound wave reaches first. In a sound source search device that detects direction, when the time difference between the sound wave signals output from each sound wave receiving means is equal to or greater than a certain value, only the signal corresponding to the earlier sound wave signal is outputted, and the time difference is set to a certain value. When it is smaller, signals corresponding to both sound wave signals are output.

According to an embodiment of the present invention, the means for generating the sound source direction detection signal includes a pair of rectangular wave signal generating means triggered by the output of each sound wave receiving means, and each sound wave receiving means and the rectangular wave signal generating means. a pair of gate means interposed between the two, whose output is inhibited by a rectangular wave signal from the other rectangular wave signal generating means; and a delay means for delaying the rectangular wave signal by a predetermined time and inputting the delayed signal to the gate means. and is provided. It is also possible to implement these functions using a microcomputer.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a block diagram of the device of the present invention applied to a traveling object moving in the direction of a sound source. This sound source search device is equipped with a pair of ultrasonic microphones lla and 11b arranged on the left and right as sound wave receiving means. Each microphone
The sound wave signals output from la and 1ib are sent to amplifier 1, respectively.
2a and 12b.

The output section of each amplifier 12a, 12b is connected to a gate circuit 1, respectively.
3a and 13b, the one-shot waveform shaping circuit 14
a, 14b. The pair of one-shot waveform shaping circuits 14a and 14b are constituted by a known multivibrator that outputs a rectangular wave with a fixed time width in response to the rising edge of an input signal. Each one-shot waveform shaping circuit 14
The outputs of a and 14b are detection signals corresponding to the direction of the sound source, respectively, and are supplied to motor drive circuits 15a and 15b to drive the left and right drive wheel motors 16a and 16b for a certain period of time, and are also output by delay circuits 17a and 17b. The signals are delayed by a predetermined time and are input to the other gate circuits 13b and 13a as gate signals.

Each gate circuit 13a, 13b is connected to a delay circuit 17b, 17a from each one-shot waveform shaping circuit 14a, 14b, respectively.
The gates are closed while the gate signals are being sent through the amplifiers 12a and 12b, that is, the outputs of the amplifiers 12a and 12b are prevented from being sent to the one-shot waveform shaping circuits 14a and 14b.

The pair of motors 16a and 16b are used to rotate the left and right drive wheels of a running object such as a toy car, so the motor 16a, which is driven by the motor drive circuit 15a connected to the microphone lla on the right side, is driven by the motor 16a on the left side. Rotate the wheel.

Motor drive circuit 1 connected to microphone llb of 11
Motor 16b driven by motor 5b rotates the right wheel. Appropriate reduction gears and clutches are interposed between each motor and the drive wheels, so that when only one drive wheel is driven, the other drive wheel follows and rotates, so that the running body moves to the left or It is configured to be able to turn to the right.

Next, signal changes and operations of each part in the sound source search device shown in FIG. 2 will be explained.

First, the sound source consists of an ultrasonic transmitter that intermittently generates ultrasonic pulses at predetermined time intervals, and its position is as shown in FIG.
Distance to #xa.

The difference in xb is smaller than a certain value, i.e. 1xa-xb
It is assumed that l<K (the shaded area in the figure). Note that the value of K is smaller than the distance d between the two microphones lla and llb (Co<K<d), and the shaded area in the figure is the area surrounded by the two hyperbolas xb - Xa = and xa - xb =. It is.

In this case, the sound source or the right microphone
, the ultrasonic pulse emitted from the sound source X reaches the microphone lla first, and then reaches the left microphone llb. Therefore, as shown in FIGS. 4A and 4B, the microphone lla on the right side outputs the signal earlier than the microphone llb on the left side by a time difference Δt. As a result, the one-shot waveform shaping circuit 14a outputs a rectangular wave signal with a time width T, as shown in FIG. 4(C). Therefore, as shown in FIG. 4(F), the motor drive circuit 15a drives the left wheel motor 16a for a certain period of time.

At this time, the rectangular wave signal from the one-shot waveform shaping circuit 14a is delayed by a time Td by the delay circuit 17a and input to the gate circuit 13b, as shown in FIG. 4(D).

Here, the delay time Td is a value obtained from the above-mentioned constant value and the ultrasonic velocity V as Td=/v. In the case of Figure 3, xb −xa
<K, and the output time difference from the left and right microphones is Δt =
(xb −xa ) /v, so the relationship between Δt and Td is Δt<Td.

Therefore, when the left microphone llb outputs a signal delayed by the time difference Δt from the right microphone lla, the rectangular wave signal from the one-shot waveform shaping circuit 14a is not input to the gate circuit 13b, and the gate circuit 13b is not closed. As shown in FIG. 4(E), the one-shot waveform shaping circuit 14b outputs a rectangular wave signal. As a result, the motor drive circuit 15b drives the right wheel motor 16b for a certain period of time as shown in FIG. 4(G).

In this way, when an ultrasonic wave is emitted from the sound source X located at the position shown in FIG.
can move straight and approach sound source X quickly.

Next, as the traveling body 3 approaches, the sound source X moves away from the shaded area in FIG. The operation in this case is as follows.

In this case as well, assuming that the sound source X is closer to the microphone 11a on the right side, the ultrasonic pulse emitted from the sound source A signal is output, and the motor drive circuit 15a drives the left wheel motor 16a for a certain period of time. At this time, the rectangular wave signal from the one-shot waveform shaping circuit 14a is delayed by the time Td by the delay circuit 17a and input to the gate circuit 13b, as in the case of FIG. 3.

However, in this case, xb-xa>K Therefore, the relationship between Δt and Td is Δt>Td It is.

Therefore, as shown in FIG. 4(B), when the left microphone llb outputs an output delayed by the time difference Δt from the right microphone lla, the one-shot waveform shaping circuit 14
The rectangular wave signal from a has already been input to the gate circuit 13b, and the gate circuit 13b is closed. Therefore, the one-shot waveform shaping circuit 14b does not output a rectangular wave signal, and the right wheel motor 16b is not driven.

Thus, only the left wheel is driven for a certain period of time, and the traveling body 3 turns to the right. The time for this direction change (time width T of the rectangular wave signal) is predetermined by the circuit constants of the one-shot waveform shaping circuit. Therefore, by setting the time T so that the traveling object changes direction by a predetermined angle, the traveling object changes direction toward the sound source every time an ultrasonic wave is emitted from the sound source, and the position of the sound source X is indicated by the diagonal line in FIG. Edited to fit into the section.

Although the sound source search device shown in FIG. 2 has been described above, the present invention is not limited thereto.

For example, in FIG. 2, each one-show waveform shaping circuit 14a, 14b is made retriggerable. This is 1
If the next trigger pulse is input while a rectangular wave is being generated with the previous trigger pulse, the generation of the rectangular wave is restarted from the time of input. Therefore, if trigger pulses are input successively within the time of one square wave signal, the output will be generated continuously. In this case, the repetition period of the sound waves intermittently generated from the sound source is made smaller than the time width T of the output signals of the one-shot waveform shaping circuits 14a and 14b.

FIG. 5 shows signal changes at various parts when the one-shot waveform shaping circuit is retriggerable and xb −xa >K.
In this case, the one-shot waveform shaping circuit 14a is driven by the output of the right microphone 11a, but it is retriggered before the output ends, so the output of the one-shot waveform shaping circuit 14a is generated continuously. do. Therefore, one show 2 connected to the left microphone itb
The gate waveform shaping circuit 14b continues to be prohibited from being triggered by the gate circuit 13b. Therefore, only the motor 12a of the left wheel continues to be driven, and the traveling body rotates clockwise. If Xa-xb >K, the rotation will naturally be in the opposite direction, counterclockwise.

On the other hand, when lxb -xa l<K, the result is as shown in FIG. That is, as mentioned above, Δt <Td
Therefore, each one-shot waveform shaping circuit 14a, 14
b are output together. Therefore, even if the next sound wave is received before each output ends, each one-shot waveform shaping circuit 14a
, 14b, each part, -to circuit 13a, 1
Blocked by 3b. Therefore, each one-shot waveform shaping circuit 14a, 14b is retriggered after one output is completed, resulting in the same operation as in the case where it is not retriggerable (see FIG. 4).

Therefore, the one-shot waveform shaping circuits 14a and 1 in FIG.
When 4b is made retriggerable, the repetition period of the sound waves intermittently generated from the transmitter as the sound source is set to 1, usually longer than the time width of the output signal of the one-shot waveform shaping circuit, and the traveling object is directed toward the sound source. For example, when the vehicle is about to collide with an obstacle, the collision is avoided by rotating the vehicle by making the repetition period of the transmitted sound wave smaller than the time width of the output signal of the one-shot waveform shaping circuit. It is possible to realize functions such as

In another embodiment, a second
FIG. 7 shows a device that realizes the same function as in the case shown in the figure.
In this embodiment, the sound wave signals output from microphones lla, llb and amplified by amplifiers 12a, 12b are input to input buffers 21a, 21 . b. C
The PU 22 takes in the signals from the input buffers 21a and 21b according to a pre-written program, determines which signal arrives first and whether the time difference is greater than a certain value, and outputs the signal if the difference is less than the certain value. Left and right motors 16a, 16b via buffers 23a, 23b
If the difference is greater than a certain value, only one motor is driven via the output buffer 23a or 23b corresponding to the microphone lla or llb that outputs the earlier output.

As yet another embodiment, a pair of microphones 11a, l
FIG. 8 shows a case in which lb is arranged on a straight line inclined at an angle θ from a right angle to the traveling direction of the traveling body 3. According to this embodiment, the distance from the sound source X to each microphone is as shown in the figure.
When the difference between xa and xb becomes smaller than the above-mentioned constant value, the left and right drive wheels 2b and 2a are driven simultaneously, and the traveling body 3 moves straight. Then, the difference between the distances glxa and xb gradually increases, and when xa - xb >K, one drive wheel 2
Only a is driven, and the traveling body 3 changes direction. By repeating this, the traveling body 3 can be moved in a spiral trajectory with respect to the sound source X.

As yet another embodiment, a device is constructed in which the wheels are driven by one motor instead of two motors as shown in FIG. It is shown in Figure 9. In this embodiment, when either one of the two one-shot waveform shaping circuits 14a, 14b is outputting, the motor 1 is output via the drive circuit 15.
6, one-shot waveform shaping circuit 14a,
An OR circuit 30 is provided between the drive circuit 14b and the drive circuit 15, and the outputs of the one-shot waveform shaping circuits 14a and 14b drive the steering solenoids 32a and 32b via the solenoid drive circuits 31a and 31b. I'm trying to change the direction of the wheels.

Also in this example, from the sound source to each microphone 11a, l.
When the difference in the distance to lb is smaller than a certain value, the left and right steering solenoids 32a and 32b are driven simultaneously, allowing the traveling object to move straight.

Note that the above embodiment uses ultrasonic waves, which has the following advantages compared to the case where audible sounds are used.

(1) Because the wavelength is short, the resolution of time differences is high.

(2) Less susceptible to normal noise.

(3) Large sound pressure can be used because people cannot hear it.

(4) It feels strange to approach an ultrasonic transmitter because people cannot hear it.

However, it goes without saying that the present device may be activated by an audible sound generated by clapping hands or the like without using a special sound source.

Further, in the above embodiment, the traveling body is moved in accordance with the direction of the sound source, but in addition to or in place of this, the direction of the sound source may be indicated by light-emitting displays on the left and right sides.

[Effects of the Invention] As described above, according to the present invention, in a device that detects the direction of a sound source depending on which of the left and right sound wave receiving means the sound reaches first, the sound waves output from each sound wave receiving means are When the time difference between the signals is greater than a certain value, only the signal corresponding to the temporally earlier sound wave signal is output, and when the time difference is smaller than the certain value, the signal corresponding to both sound wave signals is output. Therefore, when the sound source is relatively far away, it moves towards the sound source without biasing to the left or right, and by changing direction when it is close to the sound source, it can quickly indicate the direction of the sound source or approach the sound source. A sound source search device is obtained.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the sound source search device, Fig. 2 is a block diagram showing the configuration of the device of the present invention applied to a traveling object moving in the direction of the sound source, and Fig. 3 shows the position of the sound source and the arrangement of the sound wave receiving means. An explanatory diagram showing the relationship with distance; FIG. 4 is a signal waveform diagram in each part of the device in FIG. 2; FIGS. 5 and 6 are signal waveform diagrams when the rectangular wave generating means is made retriggerable. FIG. 7 is a block diagram showing the configuration when a microcomputer is used. Figure 8 is an explanatory diagram showing the operation when a pair of sound wave receiving means are arranged on a straight line inclined at a predetermined angle from a right angle to the traveling direction of the traveling body, and Figure 9 is a steering mechanism for changing the traveling direction of the traveling body. FIG. la, 1b---1 sound wave receiving means, 2a, 2b---1 drive wheel, 3-111 running body, 11a, l 1b---microphone. 12a, 12b---one amplifier, 13a, 13b---gate circuit, 14a, 14b---one shot waveform shaping circuit. 15a, 15b---Motor drive circuit, 16a, 16
b--Motor, 17a, 17b--Delay circuit.

Claims (1)

[Claims] 1. A pair of sound wave receiving means arranged at a predetermined interval and converting sound waves emitted from an arbitrary sound source into electrical signals;
A detection signal having a predetermined time width is generated by receiving a sound wave signal output from each of the sound wave receiving means, and when the time difference between the detection signals corresponding to each sound wave receiving means is equal to or greater than a certain value, a detection signal having a predetermined time width is generated. Detection signal generation means that outputs only the detection signal and outputs both detection signals when the time difference is smaller than a certain value, and a sound source direction drive that is driven by the output signal from the detection signal generation means to perform a predetermined operation. A sound source search device comprising: means. 2. The detection signal generating means is interposed between a pair of rectangular wave signal generating means triggered by the output of each sound wave receiving means, and each sound wave receiving means and the rectangular wave signal generating means, and is arranged between each sound wave receiving means and the rectangular wave signal generating means, so that each of the detection signal generating means Claim 1, comprising a pair of gate means whose output is inhibited by a rectangular wave signal from the signal generating means, and a delay means which delays the rectangular wave signal by a predetermined time and inputs the delayed signal to the gate means. The sound source search device described in Section 1. 3. The square wave signal generating means is configured to be triggered by the next sound wave signal when receiving the next sound wave signal while outputting the square wave signal, and continuously output the square wave signal. A sound source search device according to claim 2. 4. The detection signal generating means outputs only a rectangular wave signal corresponding to the temporally earlier sound wave signal when the time difference between the sound wave signals output from each of the sound wave receiving means is a certain value or more; 2. The sound source search device according to claim 1, comprising a microcomputer that outputs rectangular wave signals corresponding to both sound wave signals when the time difference is smaller than a certain value. 5. The sound wave receiving means, the detection signal generating means, and the sound source direction driving means are attached to a traveling body having drive wheels on the left and right sides, and the sound source direction driving means includes a drive circuit that operates according to the detection signal, and the drive circuit. and a motor whose energization is controlled by a motor that rotates or stops the driving wheel, and the motor is driven for a predetermined period of time in response to the detection signal to rotate the driving wheel, thereby bringing the traveling object closer to the sound source. A sound source search device according to claim 1, which is configured as follows. 6. The sound source search device according to claim 5, wherein the pair of sound wave receiving means are arranged on a straight line inclined at a predetermined angle from a right angle with respect to the traveling direction of the traveling body. 7. The sound source search device according to claim 5, wherein the sound source direction driving means includes a steering mechanism that determines the traveling direction of the traveling object according to the detection signal. 8. Claim 1, wherein the sound source comprises an ultrasonic transmitter that intermittently generates ultrasonic pulses at predetermined time intervals, and each of the pair of sound wave receiving means comprises an ultrasonic receiver. The sound source search device according to any one of items 7 to 7.