GB2076197A - Warning equipment in and for a road vehicle - Google Patents

Abstract

A warning device for giving a warning signal within a first vehicle (a) of the presence of another vehicle in the vicinity comprising a plurality of microphones (d1, d2, d3) which are mounted on the first vehicle so that each receives sounds from a pre-determined range of directions (W1, W2, W3 respectively) and a plurality of warning signal means each associated with one of the microphones (d1, d2, d3) so that warning is given of both the presence and direction of the other vehicle. The device also includes circuit means which comprise an amplifier, high-pass filter, signal control device and output device which selects those incoming sounds which will cause the warning signal means to be activated and which will silence in-car entertainment systems during operation of the warning signal means. <IMAGE>

Description

SPECIFICATION Warning equipment in and for a road vehicle The present invention relates to warning equipment for a road vehicle which provides the driver of a vehicle with a novel device whereby he can detect external noises even though all the vehicle windows are shut. The external noises which are detected are signalled to the driver by audible and/or visible means within the vehicle. The driver of a vehicle equipped with such a device is thus able to detect noises due to other vehicles which, for example, may be hooting, even though he cannot hear them directly.

Vehicles are built to be as sound-proof as possible, and many are equipped with air conditioning equipment to provide a controlled environment within the vehicle. When such air-conditioning equipment is turned on all the car windows have to be tightly closed so that the air conditioner can operate effectively. The closed windows then substantially soundproof the passenger compartment from outside noise and it is thus very difficult for the driver, especially in an air-conditioned car, to hear any external sound or noise and in particular any nearby vehicles which may be hooting.

In view of the above drawbacks the present invention is provided which in effect restores the drivers ability to detect external noises and yet still allows the driver to determine from which quarter the sounds detected originate from. This is achieved by placing several sound detecting microphones on the outside of the car which receive sound from specific directions and which are each connected via signal processing means to separate audible or visible warning means within the car and which may also be connected to a common alarm means.

A particular embodiment of the invention will now be described in more detail with reference to the accompanying drawings in which: Figure 1 is a plan view of a car equipped with a device of the present invention.

Figure 2 is a block chart.

Figure 3 is a circuit diagram of the right signal detection and amplification circuit.

Figure 4 is a circuit diagram of the highpass filter section of the right signal detector.

Figure 5 is a circuit diagram of the sudden sound control section of the right signal detector.

Figure 6 is a circuit diagram of output section.

In Fig. 1 which shows a plan view of a car equipped with the present invention and indicates the detecting areas of said invention. a denotes the car, d1 denotes the right signal detector, d2 denotes the rear signal detector, d3 denotes the left signal detector, W, denotes the detecting area of d1, W2 denotes the detecting area of d2, W3 denotes the detecting area of d3, a, denotes the front of the car, and a2 denotes the rear of the car.

When another car which is approaching the car (a) on its right quarter is hooting, detecting means d, installed in the car (a) immediately detects the hooting and converts it to an electrical signal which is then processed through amplification, filter, control and output stages and is then indicated by the warning flasher and warning alarm and warning recorder so that the driver of car (a) is made aware of the warning hoot and the direction from which it came. Similarly, he can be made aware of sounds originating from the areas W2 and W3.

As shown in Fig. 2, there are three identical but separate detection systems one of which will now be described as follows: When the signal detector in the car (a) detects the external hooting signal from the other car, the resultant electronic signal is then amplified by the amplifier. The amplified signal is then filtered by the high-pass filter.

The filtered signal will then generate a sudden voltage in a set time if the amplitude of said signal exceeds a constant value. After the sudden sound control, the said signal is forwarded into the integrated timing circuit l.C.

555. The output terminal of said l.C. 555 is connected to the power relay of which can switch on a flasher, warning alarm and warning recorder.

The warning alarm shown is connected to the output section of all three systems because it acts as a common warning device.

In Fig. 3 which is a circuit diagram of the right signal detection and amplification circuit, A, and A2 denote operational amplifiers which can each be formed by an integrated circuit.

The former can be formed by CA 324 and the latter by CA8 1 0Q or CA91 OQM, all of which are RCA products. The microphone (d) converts the sound wave into a weak voltage which is first amplified by A, and then power amplified by A2. The principle of operation of A, and A2 is well known to those skilled in the art and it is not necessary to describe it here.

The adjustable resistance R5 is a continuously variable resistance before which a digitized switch may be installed so as to change said resistance into a digitally variable resistance which is designed to adjust the output signal from A, and to select the proper signal to be amplified by A2 for input to the high-pass filter.

Q, is an FET (2SK30) which is used as a varistor. Q, feeds the said signal back to the negative end of A, so as to adjust the output signal level into a certain set range for input to the high-pass filter.

Fig. 4 shows a Butterworth high-pass filter where input is at the point X and which includes operational amplifiers OP1 and OP2 (which are numbered 741).

In Fig. 5, the filtered signal from input point Y is initially amplified by operational amplifier OP3 and will generate a sudden voltage in a time T set by R29 and G6 when the amplitude exceeds a constant value. The sudden voltage output is adjusted by R30 and amplified by Op4. It is unable to pass the zener diode ZD if it is lower than the breakdown voltage of the zener diode but any signal which is passed is amplified by Q2 for input to the integrated timing circuit l.C.

555A to generate a single resonant oscillating signal for output from the third terminal of i.C. 555A. The output signal frequency is determined by R34 and C,8. In the interest of convenience at the output terminal later on, the said third terminal of l.C. 555A is con nected to a power relay via point Z,.

The l.C. 555B in Fig. 6 is the detecting integrated timing circuit l.C. for the rear detection circuit, and the l.C. 555C is the detecting/timing integrated circuit for the left-hand detection circuit.

As shown in Fig. 6, the output terminal of the right-hand detection circuit is connected to a relay RA at the point Z,. The protective diode D2 beside the said relay RA is designed to prevent the l.C. 555A from damage by any instantaneous kickback voltage caused by operation of the relay. RA/1 denotes the first set of contacts of relay RA, RA/2 denotes the second set of contacts of relay RA; similarly, RA/3 denotes the third set of contacts of relay RC. In Fig. 6, the contacts of RA/1 and RA/2 are both represented by a normal open circuit, and the contacts of RA/3 are represented by a combined normal open circuit and normal closed circuit.

In Fig. 6, when the relay RA operates, RA/1 and RA/2 are closed, the alarm flasher PL, twinkles, and the alarm Buz (a DC type) sounds. RA/3 forms a two way switch which connects either the set recorder TA1, or the invehicle radio recorder TAo to the power source. Under normal conditions TAo is connected to the power source and when relay RA operates TA, is connected to the power source in its place. Thus whilst driving the car under normal conditions the radio-recorder will be operable. However as soon as an external warning hoot is detected, the original sound of said recorder will be cut off automatically and the set recorded hoot broadcasted instead. R35 is designated to regulate the volume of the alarm Buz.

Z2 and Z3 in Fig. 6 denote the input points of the rear and left-hand detection circuits respectively and their operating status after an input is received is omitted since it will be the same as that of Z.

The above embodiment is given by way of example and it is to be understood that many other kinds of circuit means other than wire may be used to interconnect the various elements of the invention. For example, wireless links can be used to connect the microphones to their circuit means. Such links can comprise sending and receiving stations and associated analog or digital components and interfaces, such as analog to digital convertors. In such an installation the signal detector on detecting an external noise will send a radio frequency signal to a receiver mounted within the car. The receiver is connected to the signal processing circuitry and the alarm devices connected to the circuit are thus activated.

Claims (11)

1. A device for giving a warning signal within a first vehicle of the presence of another vehicle in the vicinity comprising a plurality of microphones for receiving sound from other vehicles which microphones are mounted on the outside of the first vehicle so that each receives sound from a pre-determined range of directions and a plurality of warning signal means each associated with at least one of said microphones so that warning is given of the presence and direction of the other vehicle.

2. A device as claimed in claim 1, wherein there is a circuit linked to each of the microphones and each circuit comprises an amplifier, a high-pass filter, and a signal control device to select signals output from said filter which are due to particular sounds detected by said microphone and as a result of said selected signals to pass signals to the respective warning signal means.

3. A device as claimed in claim 1, wherein said circuits are linked to each of said microphones by means of a radio frequency link provided between a radio transmitter and a radio receiver.

4. A device as claimed in claim 1, wherein at least some of said warning signal means are visible warning means.

5. A device as claimed in any of the preceding claims wherein at least some of said warning signal means are audible warning means.

6. A device as claimed in claim 5, wherein at least some of said audible warning means comprise means for rendering a pre-recorded sound audible.

7. A device as claimed in any of the preceding claims wherein an output device is provided which controls said warning means in response to signals received from the signal control device.

8. A device as claimed in claim 7 wherein said output device automatically silences any in-vehicle sound entertainment system at the same time as activating one or more of said warning means.

9. A device as claimed in any of the preceding claims wherein said high-pass filter can be manually adjusted to increase or decrease the frequency range of signals passed through said filter.

10. A device as claimed in any of the preceding claims equipped with analog to digital convertors.

11. A device substantially as described herein with reference to the accompanying drawings.