CN2114837U - Digital automatic distance measurer - Google Patents

Abstract

The utility model discloses a digital automatic range finder used for measuring distance when an automobile is backed, comprising a square wave oscillator, a synchronous frequency divider, an amplifier, an ultrasonic emitting and receiving transducer, a filter and a timer. The timer is formed by adopting photoelectricity combination parts, and the filter comprises a double D trigger. The sensor is arranged at the tail section of the automobile, other details are arranged in driving cab, and both are connected with each other through cables. When backing the automobile, a driver can decide whether to continue backing according to the distance values displayed by number without the need of watching the rear. The utility model has the advantages of precise distance measuring, reliable working, etc.

Description

DIgital automatic distance measurer

The automatic range finder that the utility model uses when being a kind of suitable reversing automobile belongs to the distance measuring instrument technical field.

Existing reversing automobile warning device, no matter be sound, light indication, can only tell all whether automobilist's automobile back has hamper, and can't know how many distances automobile has from hamper, can only lean on the driver later to watch during reversing, whether decision continues reversing, is not easy accurately to judge the distance of reversing, especially run into rainy, dense fog or work at night, more difficulty.Therefore, often there is reversing to break buildings and casualty accident generation.

The purpose of this utility model is at the deficiencies in the prior art, and a kind of digital display type automatic range finder is provided.During reversing automobile, the driver only needs to watch the numeral on the instrument to show at pilothouse, just knows that the automobile back has or not hamper, and how many concrete distances is, thereby whether decision continues reversing; If have people or hamper to occur when reversing suddenly, instrument also can show in 20ms.No matter this instrument is daytime or night, no matter is fine or overcast and rainy etc., all can guarantee to work reliably.

The utility model utilizes ultrasound wave as emissive source, receives the hamper required time of reflection echo by measuring spontaneous being mapped to of ultrasonic pulse, converts distance again to.If choose counter clock recurrence interval T=0.6ms, then range finding is from the S(decimetre) just equal the numerical value of meter reading N.The utility model is made up of emitter, receiving trap and timer, emitter is made of square-wave oscillator, synchronous frequency divider, power amplifier and ultrasonic emitting sensor, receiving trap is made of ultrasound wave receiving sensor, amplifier and wave filter, be characterized in that timer is made of two photoelectricity combiners, the timing commencing signal of clock pulse signal, synchronous frequency divider, the count end signal of wave filter are connected with timer respectively with shows signal.Wave filter adopts a double D trigger, a diode, an electric capacity and two resistance to constitute.In order to simplify circuit structure, reduced volume, timer can adopt an integrated circuit CL102 to constitute.

The utility model compared with prior art, has automatic range numeral clear display, characteristics such as precision is high and reliable, the driver need not watch the rear during reversing, and the distance that only needs to show according to instrument just can determine whether to continue reversing, automatically the distance of measuring is 0.1～3 meter, and error can be less than ± 0.1 meter.

Fig. 1 is a structure block diagram of the present utility model; Fig. 2 is circuit theory diagrams.

The utility model can be taked as shown in drawings, and scheme realizes.The recurrence interval of square-wave oscillator (1) is 0.6ms, just be that ultrasound wave comes and goes 0.1 meter required time in air, it divides two-way output, one the road makes time clock to timer (5), the subsynchronous frequency divider in another road to 32 (2), this synchronous frequency divider decision measuring distance scope, the one tunnel outputs to timer as the timing commencing signal, another road control 40KHZ square-wave oscillator (3) makes its work and removes ultrasonic emitting sensor (8) through power amplifier (4); After ultrasound wave receiving sensor (9) receives the hamper reflection wave, convert electric signal to and send into wave filter (7) through amplifier (6), wave filter one end output timing end signal is given timer, and another road output shows signal is given charactron.Two ultrasonic sensors are contained in automobile tail, and other parts all are contained in the etui, connect with cable between the two, and it is indoor that etui is installed in car steering.Square-wave oscillator (1) and (3) can constitute V by one 412 input nand gate circuit Y1～4 and resistance R 1～4, capacitor C 1～4 _CCBe power supply, empty input end can be used as vibration whether control end, low level failure of oscillation, high level starting of oscillation in the NAND gate circuit.32 subsynchronous frequency dividers (2) can be made of one 16 system synchronous counter 74LS163 and double D trigger 74LS74 and resistance R 5, and half of double D trigger is for removing 2 circuit, and second half is a monostable circuit.Power amplifier (4) can constitute the β of low power tube T1＞100, fT＞10MHZ, P＞200mW, BV by the Technitron T1 that forms complex pipe and T2, resistance R 6 and R7, capacitor C 5 _CC＞15V, the β of power tube T2＞30, fT＞10MHZ, P＞5W, BVce＞15V.Amplifier (6) can be made of three operational amplifier TL084 and resistance R 8～15, capacitor C 6～11, and the centre frequency of this bandpass amplifier is 40KHZ, △ f ≈ ± 2KHZ, and enlargement factor Kv ≈ 2000, VEE are power supply.Wave filter (7) can be made of a double D trigger 74LS74 and diode D, capacitor C 12, resistance R 16 and R17, and a d type flip flop is formed bistable circuit, and a control end is input end of clock CP, and the other end is reset terminal R; Another d type flip flop is formed monostable circuit, and diode can be removed the noise interferences that level is lower than 0.7V, and CP must could work greater than 1.2V.Bistable circuit is upset in a single day, and later interference is just inoperative, and bistable another state is to rely on transponder pulse to realize removing exomonental interference by the zero setting end.Timer (5) is made of two photoelectricity assembling device 2 * CL102, and every circuit is formed two tens digits by decade counting unit, register, decoder driver and seven segment digital tubes.When distance during less than 0.7 meter, sound equipment just sends alerting signal, it is made of four bit comparators 7485, when comparer presets the B input end is 0011, and the function end places A＜B, first and second second and the 3rd of connecing the register units of the A input end of comparer, the 3rd and the 4th first and second of connecing the register tens of the A input end of comparer, when the number of register less than 07 the time, comparer triggers musical film (S) pronunciation by the KD482 output signal.Ultrasonic emitting and receiving sensor can adopt state-run 999 factory product, and its centre frequency is 40KHZ ± 2KHZ, and power is 1W.Cable can adopt 5 meters common two core shielding lines.C is an electric capacity among the figure, and voltage stabilizing diode can adopt 2CW51, and transistor T 1 and T2 can adopt 3DG12 and 3DK10, and power circuit is made up of integrated package 7805.

Claims (3)

1, the digital automatic range finder that uses during a kind of reversing automobile, form by emitter, receiving trap and timer, emitter is made of square-wave oscillator, synchronous frequency divider, power amplifier and ultrasonic emitting sensor, receiving trap is made of ultrasound wave receiving sensor, amplifier and wave filter, it is characterized in that timer is made of two photoelectricity assembling devices, the timing commencing signal of clock pulse signal, synchronous frequency divider, the timing end signal of wave filter are connected with timer respectively with shows signal.

2, digital automatic range finder according to claim 1, its feature adopts a double D trigger, a diode, an electric capacity and two resistance to constitute at wave filter.

3, digital automatic range finder according to claim 1 and 2 is characterized in that timer adopts two integrated circuit CL102 to constitute.

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