JPH03233389A - Body detector for automobile - Google Patents

Abstract

PURPOSE:To simplify work without drawing the wiring of an alarm in a room by multiplying the high frequency signal of an oscillation means, modulating a multiplication signal by a detection signal, and transmitting it to an alarm means in an automobile via an antenna. CONSTITUTION:The high frequency signal oscillated at an oscillator 1 is multi plied by two or three with a frequency multiplication amplifier 12, and is ampli fied with an intermediate amplifier 13. The high frequency signal is further amplified with a power amplifier 14, and is transmitted to an analog switch 18. When no body 9 to be detected approaches a sensor 3, no control signal is output from a oscillator 1, therefore, a switch 18 is turned off. When the body 9 approaches the sensor 3, the control signal is outputted from the discrimi nator 11, therefore, a controller 17 is operated, and the switch 18 is turned on. Thereby, a voice output circuit 15 is operated, and voice output is sent to a modulator 16, and modulation is applied to the high frequency signal. The output of the amplifier 14 is sent to a transmission antenna 19, and alarm output is transmitted.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention detects the approach of an object by changing capacitance,
The present invention relates to an object detection device for automobiles that provides a warning to that effect.

[Prior Art] Conventionally, as a method for detecting objects around a car when the car is parked in a garage or in a parking lot, there is a known method that utilizes a change in capacitance with respect to the object.

FIG. 3 is a block diagram showing a conventional object detection device for an automobile of this kind disclosed in, for example, Japanese Patent Application Laid-Open No. 60-111983. In the figure, (1) is an oscillator that generates a constant high frequency signal; 2) is a network connected to the output terminal of the oscillator (1) and composed of a resistor divider circuit. (
3) is a sensor connected to the dividing point of network (2) to detect the approach of an object, and is composed of an electrode plate.
Ru. (4) is a bandpass filter connected to the output terminal of the network (2) and performs noise removal and amplification processing on the high frequency output voltage from the network (2); (5) is a bandpass filter (
4) and detects the amplified signal. (6) is a voltage fluctuation detection circuit that is connected to the detector (5), detects the approaching state of an object from the falling state of the detected voltage signal, and issues an alarm command when the voltage drop exceeds a preset condition. . (7) is a driver that is connected to the voltage fluctuation detection circuit (6) and issues a drive signal in response to an alarm command; (8) is an alarm that issues an alarm based on the drive signal.

(9) is a detected object that is close to the sensor (3), and forms a capacitance C with the sensor (3).

The conventional object detection device for automobiles is configured as described above.
A high frequency signal oscillated by the oscillation RH (1) is applied to the network (2).

At this time, since the capacitance llC changes in proportion to the proximity of the sensing object (9) facing the sensor (3), the network (2) outputs an appropriately attenuated high frequency signal according to this capacitance change. Output voltage is generated. This high frequency signal has a band i1! By sending the signal to the wave amplifier (4), noise induced in the sensor (3) etc. is removed and only the high frequency component is amplified. This amplified high-frequency component is detected by a wave detector (5), and a DC voltage signal corresponding to the amplitude of the human-powered high-frequency component is sent to a voltage fluctuation detection circuit (6). The voltage fluctuation detection circuit (6) detects a falling state of the input DC voltage signal, and when the amount of voltage drop becomes less than a preset reference value, the detected object (9) is detected as having entered the dangerous area and the driver is activated. (7) Give an alarm command. Thereby, the alarm device (8) issues an alarm to that effect by sounding or lighting. Alarms mainly consist of piezoelectric buzzers and are usually installed inside the vehicle interior.

[Problems to be Solved by the Invention] The conventional object detection device for automobiles as described above detects the detection object (9) based on the change in capacitance C between the detection object (9) and the sensor (3). When detecting the approaching state, the sensor (3)
If the distance between the oscillator (1) and the circuit body including the oscillator (1) is too large, sensitivity decreases and malfunction occurs. For this reason, the sensor (3
) and the circuit body are preferably provided close to each other, and the circuit body is mounted outside the vehicle interior. However, on the other hand, there was a problem in that the wiring had to be long in order to install the alarm (8) inside the vehicle, and the work was troublesome.

The present invention was made to solve this problem, and an object of the present invention is to provide an object detection device for an automobile that eliminates the need for wiring to an alarm.

[Means for Solving the Problems] An object detection device for an automobile according to the present invention multiplies the high frequency signal of the oscillation means, modulates the multiplied signal with a detection signal,
It is provided with a transmitting means for transmitting information to an alarm means in the automobile via an antenna.

[Function] In the present invention, a high frequency signal from an oscillator is modulated with a detection signal, and is transmitted from a transmitting antenna to a receiving antenna provided in a vehicle to provide an alarm signal to alarm means in the vehicle.

[Example] The present invention will be explained below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention, (1), (3
), (5), and (9) are completely the same as the above conventional device. (10) is the detected object (
This is an amplifier that receives the detection signal of 9) and amplifies the high frequency signal from the oscillator (1), and is connected to the oscillator 0) through a resistor R and is also connected to the sensor (3). (1
1) detects the approach of an object by the detection output from the detector (5);
The discriminator that determines the separation (12) oscillates! (13) is a frequency doubling amplifier (
an intermediate amplifier that amplifies the multiplied signal from (12), (14)
is driven by the output signal from the intermediate amplifier (13),
a power amplifier that provides output to a transmitting antenna (described below);
Reference numeral (15) is an audio output circuit that reads signals from a separately provided storage medium (not shown) such as a ROM or tape recorder, and provides audio output based on the signals. (16) is a modulator that modulates the multiplied high-frequency signal from the oscillator (1) using the audio signal from the audio output circuit (15), and the input side is connected to the audio output circuit (15), and the output side is connected to the power amplifier ( 14). (17) is a discriminator (
The control signal from the audio output circuit (11) is input to the audio output circuit (15).
), and the input side is a discriminator (11)
The output side is connected to an audio output circuit (15).

(18) is an analog switch that closes (turns on) a contact when a control signal from the discriminator (11) is input, and is inserted between the power amplifier (14) and the transmitting antenna. (19) is connected to the analog switch (18),
This is a transmitting antenna that transmits the output from the power amplifier (14) to an alarm means (not shown) inside the vehicle. In addition (20
) is the sensor (3) and the detected object (9) among the above components.
) This is a circuit section of an object detection device for an automobile, which is composed of elements except for.

FIG. 2 is a side view showing the installed state of the object detection device for an automobile according to the present invention, in which (21) is an automobile;
2) is the bumper of this car (21), (23) is a radio that is a warning means installed in the car (21) in advance, (
24) is a receiving antenna. The circuit section (20) of the automobile object detection device is mounted in a part that cannot be seen from the outside at the lower part of the bumper (22).

In the automobile object detection device configured as described above, the high frequency signal oscillated by the oscillator (1) is doubled or tripled by the frequency multiplication amplifier (12), and is then multiplied by 910k.
Hz (or 1365kHz) and is amplified by an intermediate amplifier (13). The amplified high-frequency signal is further power amplified by a power amplifier (14), and then the analog switch,
18).

Here, when the detected object (9) is not approaching the sensor (3), the oscillator (11) does not output a control signal, so the analog switch (18) is turned off, and the output of the power amplifier (14) is is not supplied to the transmitting antenna (19). Therefore, no alarm output is sent.

On the other hand, when the detected object (9) approaches the sensor (3), a control signal is output from the discriminator (11), so the controller (17) operates and the analog switch (18) is turned on. becomes. As a result, the audio output circuit (15) operates, the audio output is sent to the modulator (16), and the high frequency signal is modulated. The output of the power amplifier (14) is then sent to the transmitting antenna (19), and the alarm output is transmitted. This alarm output is received by the radio (23) via the receiving antenna (24), and an alarm sound is emitted.

In the above embodiment, the following changes are made by the audio output circuit (15):
Although modulation is applied to the A unit (16), the same effect can be expected even if the modulator (16) is modulated by a constant frequency signal such as a buzzer.

Further, in the above embodiment, the frequency of the high frequency signal of the oscillator is not particularly limited, but for example, the frequency may be made variable so that the driver can select the reception frequency, or the frequency band may be widened to allow the radio to operate in the AM wave band. Alternatively, it may be possible to cover the entire FM wave band.

[Effects of the Invention] As described above, the present invention provides a conventional object detection device for an automobile with a transmitting means for multiplying the high frequency signal of the oscillating means, modulating this signal with a detection signal of the object to be detected, and transmitting the signal. Since the alarm signal is received by a radio installed in the vehicle, there is no need to run the alarm wire into the vehicle interior, which simplifies the work. Furthermore, since the transmitting equipment can be constructed using the oscillator of the automobile object detection device, there is no need to separately provide a buzzer or an audio warning speaker, and there is an effect that the cost can be further reduced.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of an object detection device for an automobile according to the present invention, Fig. 2 is a side view showing an installed state of the embodiment of Fig. 1, and Fig. 3 is a conventional object detection device for an automobile. FIG. In the figure, (1) is an oscillator, (3) is a sensor, and (5)
is a detector, (9) is an object to be detected, (11) is a discriminator, (
■2) is a frequency doubling amplifier, (13) is an intermediate amplifier, (
14) is a power amplifier, (15) is an audio output circuit, and (16) is a power amplifier.
) is the variable WJ" AHL (17) is the controller, (19) is the transmitting antenna, (24) is the receiving antenna, and C is the capacitance. In each figure, the same symbols indicate the same or equivalent parts. .

Claims (1)

[Claims] a sensor means constituted by an electrode, an oscillation means for generating a high frequency signal, a conversion means for converting a change in capacitance between a detected object and the sensor means into a change in a high frequency signal;
An object detection device for an automobile, comprising a detection means for detecting an approaching or separating state of a detected object according to a change in the high-frequency signal, and an alarm means for issuing an alarm based on a detection signal from the detection means, wherein the oscillation means An object detection device for an automobile, further comprising a transmitting means for multiplying a high frequency signal, modulating the multiplied signal with the detection signal, and transmitting the multiplied signal to the alarm means in the automobile via an antenna.