JPH0366717B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle approach warning device that detects an approaching vehicle and issues a warning.

Currently, traffic lights are installed at intersections on wide roads, but traffic lights are usually not installed on narrow roads. For this reason, convex mirrors are installed at such intersections to widen the driver's field of view.

However, when this mirror is covered with dust, it becomes difficult to see, and it becomes difficult to see when the mirror is facing the setting sun. Despite this, there were many cases where collisions occurred due to collisions between two people.

The present invention has been made in view of the above, and its purpose is to use the Doppler effect to generate a warning when a vehicle approaches, and to avoid being affected by surrounding environmental conditions. An object of the present invention is to provide a vehicle approach warning device.

When a sound wave source and an observation point are fixed at the same location, and the sound wave is emitted from the sound wave source and the sound waves reflected by an obstacle are observed at the observation point, when the obstacle does not move. The frequency of the reflected sound wave is the same as the frequency of the generated sound wave, but when the obstacle approaches the observation point, the frequency of the reflected sound wave increases, and conversely, when it moves away from the observation point, the frequency of the reflected sound wave increases. becomes lower.

This phenomenon is called the Doppler effect, and if the frequency of the emitted sound wave is f ₁ and _{the frequency of the reflected sound wave is f 2 ,} then when an obstacle approaches, f ₂ = f ₁ ( 1+u/V)>f ₁ When the object is moving away, it is given by f ₂ =f ₁ (1-u/V)<f ₁ . u is the velocity of the obstacle and V is the velocity of the sound wave.

Therefore, if a sound wave with a higher frequency than the emitted sound wave is detected among the reflected sound waves, it is possible to detect that an obstacle is approaching, and if the frequency is higher, the obstacle is closer. It can detect that you are approaching at a faster speed.
Therefore, if this obstacle is a vehicle, it is possible to detect its approach and its speed. This is not limited to sound waves, but also waves, radio waves,
The same is true even if a single wavelength laser or the like is used.

The present invention utilizes such a principle, and one embodiment thereof will be described below.

FIG. 1 is a block diagram of a vehicle approach warning device according to the embodiment.

1 is an oscillator that generates a signal with an ultrasonic frequency higher than the audible frequency; 2 is an amplifier that amplifies the ultrasonic signal; 3 is a speaker (transmission means) that generates an ultrasonic wave by the output from the amplifier 2; 4 is a A microphone (receiving means) that detects when the ultrasonic waves emitted from the speaker 3 are reflected by obstacles and enter.
It is.

The speaker 3 and microphone 4 are integrated to constitute wave signal transmitting/receiving devices 12 and 13, which will be described later, and are fixed and installed toward the vehicle travel path.

5 is an amplifier that amplifies the ultrasonic signal detected by microphone 4, and 6 is the frequency of the signal oscillated by oscillator 1.
A high pass filter 7 passes only frequency components slightly higher than _f1 , and 7 is an F/V converter that converts the frequency signal from the high pass filter 6 into a voltage signal. 8 is that F/
The voltage signal output from the V converter 7 can be used to
This is a drive circuit that drives the display 9 made of LEDs to blink. Above oscillator 1, amplifiers 2 and 5, high
The pass filter 6, the F/V converter 7, and the drive circuit 8 constitute a signal processing circuit 21. Note that the Doppler sensor includes the above-mentioned wave signal transmitting and receiving device 12,
13, and a signal processing circuit 21.

In this circuit, a reflected ultrasonic wave out of the ultrasonic waves emitted by the speaker 3 is detected by the microphone 4, and a signal oscillated by the oscillator 1 among the ultrasonic waves with a frequency f ₂ received by the microphone 4. A frequency component higher than the frequency f ₁ of is selected by a high pass filter 6 and converted to a DC voltage by an F/V converter 7,
The drive circuit 8 causes the display 9 to perform a display operation.

Therefore, even if there is a vehicle in the direction in which the ultrasonic waves are emitted,
If the vehicle is stopped or moving away, the output from the high pass filter 6 will be zero and the display 9 will not blink. on the other hand,
When a vehicle is approaching, the high pass filter 6 outputs an output with a frequency corresponding to the speed of the vehicle, so the display 9 blinks at a brightness corresponding to the height of the frequency. Therefore, it is possible to confirm that the vehicle is approaching and at what speed from the flashing and brightness of the display 9.

Furthermore, even if a person approaches on foot, the frequency of the reflected waves will be high; however,
By appropriately setting the cut-off frequency of the high pass filter 6, the display 9 can be prevented from operating.

In addition, if there is a risk that the oscillation frequency of the oscillator 1 may fluctuate, the cut-off frequency of the high-pass filter 6 is linked to the oscillation frequency of the oscillator 1. A tracking function may be added to the filter 6.

FIG. 2 shows an example of a modification of the circuit shown in FIG. ) is connected, and the drive circuit 8 is connected to the subsequent stage, and the other parts are the same as in FIG. 1.
Here, the oscillator 1, amplifiers 2 and 5, F/V converter 7, comparator 10, and drive circuit 8 constitute a signal processing circuit 22. In this example, all of the reflected waves are converted into DC voltage by F/V converter 7, and comparator 1
0 is compared with a reference voltage Vr corresponding to a frequency slightly higher than the oscillation frequency _f1 of the oscillator 1,
When a voltage higher than the reference voltage Vr is output from the F/V converter 7, the difference voltage is output to the drive circuit 8.

In this example as well, in order to avoid detecting the above-mentioned human approaching on foot, it is sufficient to set the reference voltage Vr appropriately, and in order to compensate for malfunctions due to fluctuations in the oscillation frequency of the oscillator 1, the oscillation frequency It is sufficient to perform F/V conversion on the voltage and use the voltage whose level is slightly modified as the reference voltage Vr.

The above example uses ultrasonic waves, but as mentioned above, other waves such as radio waves or laser light can also be used, and in these cases, since the frequency is high, the emitted wave It is possible to increase the frequency difference between the reflected wave and the reflected wave, and therefore it becomes easy to set a critical detection speed for distinguishing between an approaching vehicle and a person approaching on foot.

The vehicle approach warning device described above can be installed singly or in plural at an intersection, but it can also be installed on an already installed convex mirror 11, as shown in FIG.

In this FIG. 3, reference numerals 12 and 13 are transmitting/receiving devices to which the speaker 3 and microphone 4 of FIG. ing. Reference numerals 15 and 16 indicate display tubes (notification means) having a display 9 therein, which are similarly attached to the mounting plate 14 upwardly and downwardly outwardly, respectively, at an angle of approximately 45 degrees to the left and right. That is, the transceiver 12 and the display tube 15 are attached so that the angle between them is approximately 90 degrees. Transmitter/receiver 13 and display tube 16
The same is true. The transmitting/receiving device 12, the display tube 15, and other necessary circuits 21, 22, etc. constitute one set of vehicle approach warning devices, and the transmitting/receiving device 13, the display tube 16, and other necessary circuits constitute another set. A vehicle approach warning device is configured. 17 is a rain eaves and 18 is a pole.

In this way, as shown in FIG. 4, when the vehicle 19 from the direction of arrow A and the vehicle 20 from the direction of arrow B head toward the intersection when the vehicle is attached to the T alley, the following steps will be taken. Both parties can know when vehicles are approaching.

That is, one vehicle 19 is detected by the sound waves emitted from the transmitting/receiving device 12 and the display tube 15
blinks, allowing the driver of the other vehicle 20 to know that the other vehicle 19 is approaching. Also, since the other vehicle 20 is detected by the sound waves emitted from the transmitting/receiving device 13, the display cylinder 16 blinks.
The driver of one vehicle 19 can be aware of the approach of the other vehicle 20.

Furthermore, if another one of the devices shown in FIG. 3 is installed, the drivers of the vehicle 20 approaching from the direction of arrow C and the vehicle 20 approaching from the direction of arrow B can each know the proximity of the other vehicle. .

In addition, when installing this vehicle approach warning device outdoors, if there is a power line nearby, power can be supplied from the power line, but if there is no power line, solar cells may be used. I can do it. In this case, the power goes out at night and the vehicle approach warning system does not work, but the vehicle has its lights on at night, so you can check the other vehicle's lights even if the other vehicle is out of sight. It is easy to do and there is no need to worry about accidents.

In addition, in the above embodiments, the flashing display 9 was used as a warning means, but only one vehicle approach warning device is installed to detect and warn only when a vehicle approaches from one direction. In Case of,
A sounding body such as a buzzer may also be used as the notification means.

In addition, the mutual angle between the transceiver 12 and the display tube 15 in FIG.
6 is not necessarily limited to around 90 degrees, and this device may also be set at an angle corresponding to the intersection angle of the road intersection where it is to be installed, that is, an acute angle, a right angle, or an obtuse angle. Of course.

As described above, according to the present invention, sound waves, radio waves,
Since it uses waves such as a laser and utilizes the Doppler effect, it has the feature of being able to generate a warning of the approach of a buyer's vehicle that is out of sight without being affected by changes in the surrounding environment.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a vehicle approach warning device according to an embodiment of the present invention, FIG. 2 is a block diagram of a modified example of FIG. 1, and FIG. 3a is a front view of a mirror equipped with a vehicle approach warning device. 4b is a side view of the same, and FIG. 4 is an explanatory diagram of the state in which the vehicle approach warning device is used. 1... Oscillator, 2... Amplifier, 3... Speaker, 4... Microphone, 5... Amplifier, 6... High...
Pass filter, 7... F/V converter, 8... Drive circuit, 9... Display, 10... Comparator, 11...
...Mirror, 12, 13... Transmitting/receiving device, 14...
Mounting plate, 15, 16... Display tube, 17... Eaves, 18... Pole, 19, 20... Vehicle, 2
1, 22...Signal processing circuit.

Claims (1)

[Claims] 1. A vehicle approach warning device installed near an intersection, which includes a Doppler sensor and notification means 15, 16, wherein the Doppler sensor includes a wave signal transmitting/receiving device 12,
13 and signal processing circuits 21 and 22, and the wave signal transmitting/receiving devices 12 and 13 are the wave signal transmitting means 3.
The signal processing circuits 21 and 22 process the signals from the wave signal receiving device and output a detection output indicating the presence of an approaching vehicle, and the notifying means 15 and 16 is a vehicle proximity warning device that inputs the detection output of a Doppler sensor to notify other driving routes of the proximity of a vehicle.