JPS6010191A - Sound source locating apparatus - Google Patents

Abstract

PURPOSE:To simplify the circuitry by detecting the direction of a sound source depending on whether sound first reaches either right or left voice conversion means. CONSTITUTION:A pair of voice conversion means 1a and 1b are arranged on the right and left at a specified interval and convert sound of an external sound source X into an electrical signal. A pair of square wave signal generation means 2a and 2b receive the electrical signal of the means 1a and 1b and output a square wave signal with a specified time range. A detection signal genration means 3 outputs a specified detection signal responding to the earlier square signal outputted from the means 2a and 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sound source search device that searches for whether a sound source is in the left or right direction by detecting the sound source.

Relatively simple sound detection devices are used in moving objects such as toy cars that start, stop, etc. in response to specific sounds, but these conventional devices detect sounds regardless of the location or direction of the sound source. It simply converts sound into an electrical signal and sends out a signal that causes the traveling body to perform a predetermined action based on the electrical signal.

An object of the present invention is to provide a device that can detect from which direction the sound is coming from, that is, in which direction the sound source is located, with a simple circuit configuration, in addition to the conventional voice detection function. It is in.

Therefore, the present invention arranges sound conversion means such as microphones that convert sound coming from an external sound source into electrical signals at a predetermined interval on the left and right sides, and determines which sound conversion means the sound reaches first. This system detects whether the sound source is in the left or right direction and also indicates the direction of the sound source.

Further, according to an embodiment of the present invention, the direction of the detected sound source is displayed by a pair of light emitting elements, or by pointing the vehicle equipped with the device of the present invention toward the sound source.
Can be visually recognized.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

To explain with reference to FIG. 1, the sound source search device of the present invention comprises a sound converting means that is arranged at a predetermined interval d on the left and right sides and is composed of a pair of microphones that convert sound from an external sound source X into an electrical signal. a pair of rectangular wave signal generating means 2a, which are connected to each of the voice converting means 1a, lb, and output a rectangular wave signal having a predetermined time width upon receiving the electric signal from each voice converting means 1a, lb; Uii. It is growing.

In this 1° source search device, the sound emitted from the sound source X reaches the left and right voice conversion means 1a, lb and is converted into an electrical signal.
, lb are respectively xi and x2, and the sound source X is closer to the voice converting means 1a (xi < x2),
The sound waves first reach the voice conversion means 1a, and then reach the voice conversion means 1b. The speed of sound waves is 340m
/s, the arrival time difference is Δt = (x2
-xl ) /340 [secl. here,
The distance between the two voice conversion means 1a and 15 is 1@d=5cm,
Assuming that the distance from the sound source X to the straight line connecting the two voice conversion means = 2 m, and the bias angle θ from the center of the two voice conversion means to the sound source X = 300, x2 - xi = approximately 25 m.
m, the difference in arrival time of the sound waves to the voice conversion means is
Δt=approximately 73.5 p-sec.

In this way, when the sound source is biased to either the left or right side, the sound reaches the two audio conversion means with the above-mentioned time difference Δt. Since the rectangular wave signal generating means 2a and 2b connected to each voice converting means 1a and lb generate a rectangular wave signal with a predetermined time width (several seconds in the embodiment described later), immediately after the first sound arrives. If noise or other sounds enter the voice conversion means, they will not be accepted by the device.

The detection signal generating means 3 and 5 receive the rectangular wave signals output with the time difference ΔE from the two rectangular wave signal generating means and generate a detection signal corresponding to the earlier rectangular wave signal. Therefore, from this detection signal, it can be determined which of the left and right voice converting means the sound wave reached first, and as a result, it can be indicated in which direction the sound source is located, left or right.

Next, FIG. 2 is a circuit diagram of a sound source search device equipped with a mechanism for specifically indicating the direction of a sound source.

This device is equipped with a pair of capacitor microphones lla and llb as audio conversion means, and two condenser microphones each as means for amplifying the audio signal and generating a rectangular wave signal.
The device includes a pair of one-shot waveform shaping circuits 12a and 12b each including one transistor and one capacitor, and means for receiving rectangular wave signals from these waveform shaping circuits and outputting the aforementioned detection signal. As such, it is equipped with a logic circuit 13 consisting of two NOR elements 13a and 13b.

The output terminals of the NOR elements 13a and 13b constituting the output section of the logic circuit 13 are connected to the NOT element 14a, respectively.
14b and a resistor R3, it is connected to sound source direction indicating means 15, which will be described later.

To further explain the circuit of FIG. 2, each microphone lla, flb and each waveform shaping circuit 12a, 12b has a power switch S1. Resistor RO and capacitor CO
A voltage obtained by appropriately stepping down a predetermined power supply voltage (+9V in this case) is applied to each of the six microphones 11 through
One end of a, llb is connected to the input side transistor Tr of each waveform shaping circuit via a variable resistor RX and a capacitor C.
connected to the base of i.

The waveform shaping circuits 12a and 12b each include two transistors Tri and Tr2, a capacitor C2, and resistors R5 to R.
8 are connected as shown in the figure, but in reality the values of each circuit element do not completely match, so in order to correct this, the output side transistor of one waveform shaping circuit 12b is The resistor R8° connected to Tr2 is used as a variable resistor.

The outputs of the waveform shaping circuits 12a and 12b are transmitted from the collector of the output side transistor Tr2 through the resistor R2, respectively.
The signal is input to each NOR element 13a, 13b of the logic circuit 13. And each N.

The outputs of the R elements 13a and 13b are sent to the NOT elements 14a and 14b, respectively, as the aforementioned detection signals, while each is supplied to the other NOR element as another input. The operation of these two NOR elements will be explained in detail later.

The sound source direction indicating means 15 includes a NOR element 13a,
13bc7) Two transistors Tr connected to the output terminal via NOT elements 14a, 14b and resistor R3
3. A pair of drive circuits 15a and 15b consisting of Tr4
is connected to the output side transistor Tr4 of each drive circuit, and is connected to a predetermined power supply (+3V in this case) by turning it on and off.
) are provided with a pair of motors Ml and M2 whose energization is controlled. It should be noted that between this sound source direction indicating means and the power source, a 0N-
A power switch S2 to turn off is connected, and a noise prevention capacitor C3 is connected in parallel to each motor.

The pair of motors M1 and M2 of this sound source direction indicating means 15 are for rotating a pair of left and right drive wheels of a running object such as a toy car, and a suitable gear is provided between each motor and the drive wheels. A clutch is interposed so that when only one drive wheel is driven, the other drive wheel follows and rotates, thereby allowing the traveling body to change direction to the left or right.

The values of each resistor and capacitor in the circuit of FIG. 2 are as follows.

-1 is ΩRO=2.2, R1=15, R2=100
K.

R3=lOK, R1=100K±α.

R4=75, R5=10M, R6=330K.

R7 = 100K, R8 = 30, R8° = 30 and the earth α capacitor is F Co = 47. CI =0.022. C2=0.4
7°C3=0.047 Since the sound source search device shown in FIG. 2 is configured as described above, when a sound is emitted from the sound source, it operates as follows.

Assuming that the sound @X is located to the right of the vehicle equipped with this sound source search device, the sound wave will reach the microphone lla on the right side first, and the above-mentioned Δ will be reached after the lapse of time. , reaches the left microphone llb. Therefore, the audio signals output from the microphones lla and flb are expressed as voltages at points A and A° in FIG. 2, respectively, and Δt as shown in FIGS. Each one-shot waveform shaping circuit 12 has a time difference of
a, 12b.

Correspondingly, each one-shot waveform shaping circuit 12a,
12b, the collector voltage of the input transistor Tri (the voltage at points B and B' in FIG. 2) changes as shown in FIG. 3 (B) and (B'), respectively, and the output of each waveform shaping circuit changes. , that is, the collector voltage of the output side transistor Tr2 (voltage at points C and Co in FIG. 2) is:
As shown in FIGS. 3(C) and 3(C'), a negative rectangular wave signal is amplified by the two transistors and is output to each NOR element 13a of the logic circuit 13.

13b.

Here, the output of the logic circuit 13 (voltage at points D and D')
is the high (H) and low (L) of the input (voltage at points C and Co)
The following table corresponds to this.

This is a case where the two inputs fall from H to L at exactly the same time, but this almost never happens in practice.

As is clear from the table above, when no sound waves enter either the left or right microbons, each waveform shaping circuit 12g, 12
Since the outputs of b (points C and C' (7) voltages) are both H, the pair of outputs of the logic circuit 13 (points C and D' voltage) are both L (■ in Table 2). . However, when the sound wave reaches the right microphone as described above, the output of the waveform shaping circuit 12a changes at time t= as shown in FIG. 3(C).
changes from H to L at tl, and on the other hand, the waveform shaping circuit 12b
Since the output of the logic circuit 13 does not change, the output of one NOR element 13a of the logic circuit 13 becomes H, and the output of the other NOR element 13b remains L, as shown in FIGS. 3(D) and (D'). Yes (■ in Table 2).

When the sound wave reaches the microphone on the left side after the time Δ has elapsed, as shown in FIG. 3 (Co), at time t1°
At =tl+Δt, the output of the waveform shaping circuit 12b also changes from H to L.
become. However, even if one of the two inputs of the NOR element 13b becomes L, as long as the other (output of the NOR element 13a) remains H, the output of the NOR element 13b remains at L and does not change.

The output (voltage at point 0) from the waveform shaping circuit 12a connected to the right microphone returns from L to H at time t2=tl+T after a time T predetermined by the circuit constant has elapsed. At this time, the output of the waveform shaping circuit 12b (voltage at point C') connected to the left microphone remains L, so the output of the NOR element 13a of the logic circuit 13 (voltage at point D) becomes L, and the other , the output of the NOR element 13b (
The voltage at point D' becomes H (■ in the table above).

After that, at time t2° after a further period of Δ has elapsed, the output of the waveform shaping circuit 12b (voltage at point C°) connected to the left microphone also returns from L to H, so the logic circuit 13 determines whether the two outputs are also returns to the L state (■ in the table above).

Thus, when a sound is emitted from the sound source X located to the right, a rectangular wave signal as shown in FIG. 3(D) is sent to the output terminal of the NOR element 13a of the logic circuit 13.

Then, this rectangular wave signal is transmitted to the third wave by the NOT element 14a.
The signal is inverted to a negative signal as shown in FIG. 3E, and applied to one drive circuit 15a of the inf source direction indicating means 15 via a resistor R3.

In the drive circuit 15a, when the negative rectangular wave signal is applied to the base of the input side transistor Tr3, this transistor Tr3 is turned on, and therefore the output side transistor ↑r4
is also turned on. As a result, a drive current flows through the motor M1, causing the motor to rotate. In this case, if the motor Ml of the drive circuit 15a is set in advance to rotate the left drive wheel of the traveling body in the forward direction, the traveling body changes direction to the right, that is, toward the direction of the sound source. This direction change lasts for the time width (T in Figure 3) of the rectangular wave signal (T in Figure 3) while the motor is rotating [111, that is, the logic circuit 13; It is predetermined by the circuit constants of the shaping circuit.

Therefore, by setting the driving time T of the motor so that the traveling object changes direction by, for example, 45 degrees, the traveling object can move closer to the sound source each time a sound is emitted from the sound source.

As shown in FIG. 3(D') and described above, at time t2 when the rectangular wave signal from the output terminal of the NOR element 13a of the logic circuit 13 ends, a pulse signal is output from the other NOR element 13b. Ru. However, since the time width is the above-mentioned time difference Δt and is usually on the order of psec, in such a short time, the other motor M2 of the sound source direction indicating means 15 connected to the NOR element 13b (this (for changing the direction of the traveling object to the left) cannot be driven, so it has no practical effect.

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

For example, the above device is equipped with a mechanism that uses a motor to drive the left and right drive wheels of the vehicle to change the direction of the vehicle in the direction of the sound source as a means of indicating the direction of the sound source based on the detection signal. In addition to or in place of the motor, a pair of light emitting elements may be connected, and the direction of the sound source may be indicated by the light emitting display.

In addition, in the above embodiment, a simple logic circuit consisting of two NOR elements is used as a means for outputting a detection signal indicating which of the left and right microphones the sound wave reached first, but there are other possibilities. ! l! A similar structure may be constructed by combining elements.

As described above, according to the present invention, the direction of the sound source is detected based on whether the sound reaches the left or right voice conversion means first, so the sound source search that indicates the direction of the sound source with a simple circuit configuration A device is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the device of the present invention, and FIG.
The figure is a circuit diagram of an apparatus of the present invention having means for specifically indicating the direction of the sound source, and FIG. 3 is a voltage waveform diagram at each point in the circuit of FIG. 2. la, lb--111 voice converting means; 2a, 2b---1-chip wave signal generating means; 3--111 detection signal generating means. 11 a, 1 lb -----1 R'Cj*n, 12a
, 12b---One-shot waveform shaping circuit, 13
---One wheel logic circuit, 13 a, l 3. b---NOR element, 14 a
, 14b----NOT element, 15----one sound source direction indicating means, 15a, 15b----one drive circuit

Claims (1)

[Scope of Claims] ], a pair of voice conversion means arranged at a predetermined interval on the left and right sides and converting sound from an external sound source into an electrical signal; and a pair of voice conversion means connected to each of the voice conversion means; a pair of rectangular wave signal generating means that receives an electrical signal from the means and outputs a rectangular wave signal having a predetermined time width; and a rectangular wave that is earlier in time among the outputs from the pair of rectangular wave signal generating means. 1. A sound source search device comprising: detection signal generating means for outputting a predetermined detection signal in response to the signal. 2. A pair of audio converting means arranged at a predetermined interval on the left and right and converting sound from an external sound source into an electrical signal; a pair of rectangular wave signal generating means for outputting a rectangular wave signal having a predetermined time width in response to the received signal, and a pair of output sections corresponding to the pair of rectangular wave signal generating means, which outputs a rectangular wave signal having a predetermined time width. a detection signal generation means that outputs a predetermined detection signal to an output section corresponding to the rectangular wave signal generation means that outputs the signal; and a detection signal generation means connected to each of the pair of output sections of the detection signal generation means and energized by the detection signal. and a sound source direction indicating means for indicating whether the sound source is located in the left or right direction. 3. The sound source according to claim 2, wherein the sound source direction indicating means is constituted by a pair of drive circuits that are activated upon receiving the detection signal, and a pair of light emitting elements driven by the drive circuits. Exploration device. 4. The audio conversion means, the rectangular wave signal generation means, the detection signal generation means, and the sound source direction indicating means are attached to a traveling body having a pair of left and right drive wheels, and the sound source direction indicating means receives the detection signal. It is composed of a pair of drive circuits that operate as shown in FIG. 3. The sound source search device according to claim 2, wherein the traveling body is directed in the direction of the sound source by rotating a drive wheel.