KR970000546B1 - Vehicle backward tacket sensing apparatus - Google Patents

Abstract

While driving backward, the transmitter emits an ultrasonic wave to the surrounding object that is in the way. The receiver(101) receives the wave as it comes back after being reflected on the object. The microcomputer(105), while the driver is manipulating the shifting gear, controls to light the lamp and to power on the sensor to detect the obstacle and recognizes the distance from the object, generating the warning sounds according to the distance from the object. The reset circuit(104) initializes the total system when it powers on the microcomputer then the standard clock generating circuit(103) provides the standard clock which is necessary for the movement of microcomputer(105).

Description

Vehicle rear object detection device

1 is a block diagram of an embodiment of a rear object detection apparatus for a vehicle according to the present invention.

2 is a circuit diagram showing in detail the parts of FIG.

3 is an ultrasonic signal waveform diagram for explaining an embodiment of the present invention.

4 is a detailed circuit diagram of the remote control reception detector U3 of FIG.

5 is a flow chart for measuring the distance from the vehicle rear object detection result according to the present invention and the alarm and display control according to the measurement result.

FIG. 6 is a flowchart showing concrete steps of FIG. 5.

FIG. 7 is a circuit diagram for generating first and second power supplies Vcc1 and Vcc2 for driving each part of FIG.

FIG. 8 is a view illustrating a sensing device for detecting an object around a vehicle by installing the rear object detecting apparatus of FIG. 1 in a rear bumper or a similar position of the vehicle.

The present invention relates to a device for alarming according to the detection result of the surrounding objects during the operation of the vehicle, in particular for the object (fixed object or floating object) appearing within a certain range of the automatic rear automatically detects the distance in which the driver is located in advance The present invention relates to a rear object detection device for a vehicle capable of alerting a user to a warning.

In general, the rear detection method of a vehicle uses a rearview mirror or an expensive video camera system. However, such a method of detecting the rear object of the vehicle can only detect the presence or absence of the object behind the vehicle. For example, the detected object could not know exactly how far it was from the vehicle and thus could not park safely. In addition, there was no safe parking countermeasure for blind spots due to anxiety in front of the driver. In addition, the video camera method has a problem in that the system is expensive and cannot be widely applied.

Conventional methods for resolving the above problems have a method of applying infrared or ultrasonic properties. The technique using the ultrasonic characteristics will be understood in more detail in the publication No. 90-7037 of Patent Publication No. 2041 issued by the Korean Intellectual Property Office.

The infrared method uses a color sensitive characteristic of infrared rays, and this method has a problem in that accurate distance measurement during parking cannot be accurately measured because the color sensitive characteristic is poor. . For example, this method produces a significant error when infrared rays for white and black are reflected from an object, so accurate distance measurements cannot be expected, and transparent objects are not detected. The infrared ray treatment method has a problem of using an infrared ray having a different wavelength from the infrared ray generated from the object. The method of using ultrasonic waves disclosed in the above-mentioned publication No. 90-7037 can solve some of the problems caused when using infrared rays, but because the ultrasonic device that needs to form a narrow beam must be used, the area that can be detected is narrow. This is followed by commercial restrictions that can only be used. In order to solve this problem, there are complicated installations and economic burdens that require the use of a large number of ultrasonic devices to increase reliability according to the range of use, and simultaneous operation at a long distance and at a short distance is impossible due to the problem of AGC (automatic gain control) characteristics. . In addition, this method has a lot of seasonal constraints such as temperature compensation in the circuit diagram, which makes the circuit operation state unstable according to the season, resulting in an inoperable state in the middle of winter, and a malfunction in the middle of summer.

In addition, since the principle of this method is to measure the difference in reflectance of the reflected ultrasonic waves, there are various problems such as a very narrow detection range and a decrease in reliability.

Accordingly, an object of the present invention is to provide a device capable of detecting an object in a wide range by installing a special ultrasonic transceiving module with a predetermined interval at the rear of the vehicle to measure the round trip time received from the ultrasonic transmission signal.

It is another object of the present invention to provide a device for safe parking by allowing the driver to easily and accurately know the position of the rear obstacle by changing the warning tone and the lamp display color according to the distance to the object located from the vehicle when the vehicle is backed up. Is in.

Still another object of the present invention is to provide an apparatus capable of automatically compensating a sensing change value according to a season and temperature change to increase the reliability of detecting a vehicle backward obstacle.

Another object of the present invention is to provide a device that can be safely parked even when the clock is bad weather or the car stricken.

According to an aspect of the present invention, there is provided a transmitter for transmitting ultrasonic waves when the vehicle retracts, a receiver for receiving ultrasonic waves reflected from an object with respect to the ultrasonic waves transmitted from the transmitter, and receiving the ultrasonic waves transmitted from the transmitter. After measuring the reflection time and determining the distance to the object from the measured value, the control unit for generating and displaying a warning sound, i.e. controlling the driver to easily recognize when the driver is within a certain range, and the reset for initializing when the power is supplied to the control unit. A reference clock generation circuit for providing a reference clock for operation of the controller, a test method changer for providing a change signal for a functional test to the controller, and when the object reaches a certain range from the vehicle, An alarm circuit for generating an alarm sound according to an alarm generation control signal generated from a control unit; When the object reaches within a predetermined range from the vehicle, it characterized in that it comprises a display unit for displaying the distance to the object according to the measured distance processed by the controller.

In the present invention, when reversing the vehicle, the control unit controls the ultrasonic wave to be emitted from the transmitter, and the receiver receives the control by the controller to convert the distance from the object. When the converted distance reaches a predetermined range, the alarm sound is generated differently according to the converted distance, and the display is changed on the display to allow safe parking.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, and it should be noted that elements having the same function in the drawings use the same reference numerals.

1 is a block diagram according to the present invention, which includes a transmitter 109 for transmitting ultrasonic waves to an object around a vehicle, a reference clock generation circuit 103 for providing a reference clock, and ultrasonic waves transmitted from the transmitter 109. Receives the ultrasonic waves reflected through the automatic gain control and receives the temperature compensation of the signal according to the temperature change of the season and ambient conditions, and controls the lighting of the lamp when operating the reverse gear to reverse the driving vehicle And control driving of the driving power for sensing, receive a reference clock from the reference clock generation circuit 103, divide 1 / n to generate an ultrasonic signal, and receive and reflect the transmitted ultrasound of the transmitter 109 from the receiver 101. After determining the distance to the object from the measurement of time, the alarm sound is generated and displayed for each distance so that the driver can easily recognize when it is within a certain range. ECOM 105, a reset circuit 104 for initializing the power supply to the microcomputer 105, and the test method changing unit for connecting the microcomputer 105 to the output terminal (RA3) to provide a signal for a functional test 108, an alarm circuit 106 for generating an alarm sound distinguished at every distance interval with the object according to the alarm generation control signal generated from the microcomputer 105 when the object reaches a predetermined range from the vehicle; LED unit 110 for distinguishing the distance between the object and the object by a control signal according to a value corresponding to the distance output from the micom 105 when the object reaches within a predetermined range from the vehicle, and the micom A lamp driving circuit 107 connected to the 105 to control driving of the LED unit 110, and an interrupt signal to the micom 105 from the output of the receiver 101 connected to the microcomputer 105; Provided An interrupt control circuit 102.

On the other hand, the transmitter 109 transmits the ultrasonic wave to the surrounding object which becomes an obstacle when the vehicle reverses. The receiver 101 receives the ultrasonic wave transmitted from the transmitter 109 through an object. In addition, the receiving unit 101 is spaced apart at predetermined intervals on a horizontal straight line to increase the receiving efficiency as the ultrasonic wave transmitted from the transmitting unit 109 is reflected from the object. The transceivers 101 and 109 are installed in the rear bumper to detect a vehicle backward obstacle as a body. The microcomputer 105 controls the lighting of the lamp when the driver operates the reverse gear to reverse the vehicle, and controls the input of the power for detecting the obstacle, and then transmits the ultrasonic wave of the transmitting unit 109 to the receiving unit 101. The distance from the object is determined by measuring the time reflected from the object after receiving from, and controls to generate and display a warning sound distinguished according to the distance from the obstacle object so that the driver can easily recognize the object within a certain range. The reset circuit 104 initializes the entire system when the power is supplied to the microcomputer 105. The reference clock generation circuit 103 provides a reference clock necessary for the operation of the microcomputer 105. The test range changing unit 108 provides a signal for changing a function test to the microcomputer 105. The alarm circuit 106 generates an alarm sound according to the alarm sound generation control signal generated from the microcomputer 105 when the obstacle reaches a predetermined range from the vehicle when the vehicle reverses. The LED unit 110 displays the distance from the obstacle by a control signal corresponding to the distance value converted by the microcomputer 105 when the obstacle reaches a predetermined range from the vehicle. The lamp driving circuit 107 is connected to the microcomputer 105 to control the driving of the LED unit 110. The interrupt control circuit 102 is connected to the microcomputer 105 to provide an interrupt signal to the microcomputer 105 from the output of the receiver 101. Except the transmission and reception unit 101, 109 as one body may be installed in a position where the internal driver of the vehicle can easily check the state.

That is, in order to implement the present invention, the transmitting / receiving units 101 and 109 for the ultrasonic waves are mounted inside the rear bumper of the vehicle in which the backward obstacle can be easily detected by being mounted inside the fabricated as shown in FIG. 8A.

8B is a front view of 8A, in which 802 is an ultrasonic wave emitting portion radiated from the transmitting unit 109, and 803 is for receiving the ultrasonic wave reflected from an obstacle in the receiving unit 101; Ultrasonic receiver.

(8C) is a cross-sectional view taken along line B-B 'of (8B), and (8D) is a cross-sectional view taken along line A-A' of (8B).

In (8C), 804 is rounded to 2-R20 from the center, 805 is straightened at a certain angle, and (8D) is treated as a straight line at different angles at 807 and 809 from the center to prevent obstacles. It helps to detect the obstacles in a wide range of surroundings of the vehicle while helping to make accurate detection by reciprocating the ultrasonic signal.

FIG. 2 is a detailed circuit diagram of FIG. 1, and the sensor including the ultrasonic transceiver module of FIG. 2 is mounted in a case as shown in FIG. 8 to facilitate the detection of a driver object in a rear bumper or a vehicle that becomes the rear end of the vehicle. Is installed on. In order to prevent contact with an obstacle or sudden shock when parking or driving backward, the detector may display a distinction according to the distance when reaching a certain dangerous distance and generate an alarm sound for easy recognition. Direct assistance with safe parking or driving.

To this end, the microcomputer 105 generates a 40 KHz ultrasonic wave 100 MHz of the high-definition 4 MHz generated by the crystal oscillator X1 through the resistor R7 to the output terminal RA1 as shown in FIG. 3. This signal receives the basic clock (4KHz) generated from the crystal oscillator (X1) to generate an ultrasonic signal divided by 1/100 in consideration of the ambient temperature change and the voltage change inside the microcomputer 105. Capacitors C1 and C2 connected to the crystal oscillator X1 are used for parasitic oscillation prevention. The signal generated according to the predetermined result is inputted to the bases of the transistors Q2 and Q3 through the resistor R5 through the ultrasonic waves, and the input signal is applied to the transistors Q2 and Q3 and amplified by a push-pull, followed by direct current. Through the blocking capacitor C5, it is sent to the transmitting end Tx. Here, the resistor R6 is an output stabilizing resistor, and the transmitted ultrasonic waves are reflected from the obstacle behind the vehicle. The reflected ultrasonic waves are received by the receiver 101. The receiver 101 is configured as shown in FIG. Ultrasonic receiving signal reflected from the object is input through the receiving terminal (Rx) and automatic gain control (hereinafter referred to as AGC) through a circuit composed of an automatic gain control resistor (R11) and capacitor (C6) and temperature compensation thermistor (TH1) ) Is adjusted and temperature compensation is made by seasonal and ambient temperature changes. That is, the signal passing through the receiving amplifier 1 of the receiving unit 101 is detected and amplified by the received ultrasonic signal processed by the automatic gain control and temperature compensation in the remote control sensor amplifier U3 of GL3274 of Venus Korea. The amplified signal is made to the appropriate level required by the band pass filter 4 of the next stage in the limit amplifier 3. The signal processed by the limit amplifier 3 is set to a desired signal frequency by the center frequency adjusting resistor R12 in the band pass filter 4, and after selecting only an ultrasonic signal among the transmitted signals, the second noise signal is a capacitor. It removes by (C7). The noise-free signal is compared with a reference voltage already set in the voltage comparator 5 to select a signal having a reference voltage or more. The signal above the reference voltage is again integrated by the integrating capacitor C8 of the integrator 6 and converted to the required voltage level in the voltage level matching circuit 7 of the next stage. The overall configuration of FIG. 4, that is, the overall configuration by the voltage level matching circuit 7 from the receiving amplifier 1 is composed of several resistors and capacitors in one integrated circuit, so that it is possible to implement the conventional circuit by individual components. Relatively superior in reliability. The output of the remote control detection amplifier U3 is input to the de-flop U2 of the interrupt control circuit 102. The interrupt control circuit 102 consists of a de-flip flop U2 to latch the output of the remote control detection amplifier U3. The output of the remote control sense amplifier U3 is applied to the RTCC stage 3 of the micon 105 to cause an interrupt.

When the output signal of the receiver 101 is applied to the clock terminal CLK of the flip-flop U2, the operation of the interrupt control circuit 102 is performed. ) Is from high to low (H is 5V equivalent voltage, L is 0.8V or less GND state). After checking the low state, the microcomputer 105 processes the internally and outputs a low to the output terminal RA2 to clear the deflip-flop U2 and wait for input of the next signal.

As described above, the microcomputer 105 recognizes the input of the received signal reflected from the obstacle according to the transmission of the ultrasonic signal by the interrupt operation. The microcomputer 105 calculates time versus distance from the result of detecting the rear object by a program as shown in the flowchart of FIG. 5 when the interrupter is caught. The microcomputer 105 inputs a control signal to the alarm circuit 106 to generate an alarm sound corresponding to the corresponding distance and generates an alarm sound, and the lamp driving circuit 107 to inform the distance between the vehicle and the obstacle. ) To turn on the LED unit 110. Therefore, the driver may check the distance and state according to the alarm sound and the indication generated by distance from the object so as to accurately park or drive from an obstacle behind the vehicle and drive safely.

FIG. 5 is a control flow chart for generating an alarm sound and displaying a caution according to a distance measurement with an obstacle when driving a vehicle in the present invention. The first step of designating each port input / output condition and searching for the first-n level is described above. A second step of processing the first-n level according to the first-n level of the first step and transmitting ultrasonic waves for distance measurement to receive the ultrasonic waves reflected from the object; and in the second step, The third step of converting the distance by comparing the time variable with the received result value; and comparing the distance value converted in the third step with a preset value according to the processed distance level, and when it is applicable to the rear of the vehicle. And a fourth step of generating an indication of the detected distance from the obstacle and generating an alarm sound.

Herein, the process of FIG. 5 will be described in more detail. When the driver operates the reverse gear for reversing the vehicle, the reverse lamp is turned on. In FIG. 2, power is inputted to the device of the present invention so that the resistor R1, When the microcomputer 105 is reset by the reset circuit 104 received by the diode D1 and the capacitor C10, the program of FIG. 5 is operated within 0.5 seconds after the power is applied.

In the reset circuit 104, the diode D1 is for high speed discharge of the capacitor 10, and the resistor R1 is a load resistor.

When the program is started in step (5a), the microcomputer 105 sets the output port of port A (RA0 to RA3) and sets port B (RB0 to RB7) as the input port in step (5a). When the memory is initialized, LED1 to LED9 of the timer, buzzer (PZ) and LED display unit 107 are turned off, and the effective radiation time of 40KHz (duty: high: 10, low: 70) is used as the on / off timer of the transmission / reception signal. Decide Then, after detecting the rear object by self-diagnosis according to the surrounding condition of the vehicle, each state variable is transferred to the internal main memory of the microcomputer 105, and then assigned according to the program of each sub-process in (5b, 5c, 5d). do. Subsequently, the reference frequency (4 MHz) generated by the crystal oscillator (X1) is divided by 1/100 to output an ultrasonic signal of 40 KHz to the output terminal RA1 in the process (5e), amplified by the transistors Q2 and Q3, and then transmitted. It transmits in the process (5e) through stage (Tx).

The ultrasonic frequency applied in the embodiment of the present invention is changed by the temperature change and the power supply voltage by using a ring oscillator oscillator circuit using a timer IC, an operational amplifier, or a C-MOS logic IC, which is an ultrasonic generator circuit used in another apparatus. Although the oscillation frequency is unstable, in the present invention, since a highly stable fundamental frequency is divided into one hundredth by a 4MHz crystal oscillator, the change of the ultrasonic signal frequency is hardly changed with respect to temperature and power voltage change. In operation 5f, the receiving unit 101 receives an ultrasonic signal emitted from an object emitted from an object behind the vehicle. When the received signal is applied to the interrupt control circuit 102 to interrupt the microcomputer 106 from the output (5f), the microcomputer 105 compares the various time variables and the comparison distance stored in the internal program in the process (5g). In operation 5h, the result is compared with the data set according to the distance level, and the alarm circuit 106 and the lamp driving circuit 107 are controlled in step 5i to generate the LED lamp display and the warning sound. Repeatedly up to the 2nd-n level by the above execution method. (In this case, the LED lamp display and warning sound are maintained as long as there is no change of state.) That is, the distance-specific steps that can be measured are the programs of steps 3 to 8 Can be set arbitrarily.

FIG. 5 illustrates the processes (5a)-(5i) in detail, and FIG. 6 shows the processes (5a) and (5b) of FIG. 5 in detail, and the microcomputer 105 inputs each port in process (6a). Determine whether it is a port or an output port, and set it as the initial state. When the reverse gear is operated in step (6b), the power supply is set to zero so as to be applied to the apparatus of the present invention to initialize the initialization global memory for setting basic parameters and initial conditions. In the following (6c) process, each timer is cleared, and the alarm circuit 106 and the LED unit 110 are turned off. In step (6d), each timer (transmission on / off, reception detection, 40KHz, bit on / off pulse, timer output detection) is determined to a predetermined value to realize the present invention, and an initial condition is made, a buzzer, and an LED are Off, and determines the effective firing time of the 40KHz transmission frequency. The timer that determines 40KHz transmission on / off is designed to produce the most basic time value for calculating time (T) and distance (L). In the process of (5c) and (5d), the first-n level is searched to detect the detection distance from the object to be processed when the vehicle reverses. That is, in step (5c), the distance to the object is set to be executed by dividing the sensing distance to be processed in units of 1 to 50 cm and 50 to 100 cm. In step 5e, a 40 KHz (25 Hz) ultrasonic signal is generated.

Referring to FIG. 6B, the 40KHz (25Hz) ultrasonic wave generation process as shown in FIG. 3 is described in detail. In (6e), the transmit ON flag is set to 0 and masked with the reception check port 1 to 40KHz [Duty 30 Set the number of high (high) and 70 (low) frequencies (how many 40KHz periods are to be transmitted) by the timer and the number of pulses, and generate the transmit frequency in step (6f), but return the signal by hitting the object. In order to increase the sensitivity and improve the accuracy, 32 frequencies are transmitted and output to the output terminal RA1 in consideration of the ultrasonic characteristics. When the microcomputer 105 counts the number of transmit frequency pulses and generates 32 in the process (6g) When the count is 32 in the process (6g), the reset signal is generated to the output terminal RA1 of the microcomputer 105 in the process (6h).

The transmitted ultrasonic waves are reflected from an object and input to the remote control sensing amplifier U3 through the receiving end Rx. Compensating the temperature according to the seasonal change in amplifying the received signal in the remote control sense amplifier (U3), and automatically adjusts the gain, to prevent the overload of the reception level, and to filter it in a predetermined band to compare the input voltage level After integration, the voltage is integrated into the predetermined voltage level and input to the interrupt control circuit 102.

The interrupt control circuit 102 interrupts the microcomputer 105 by latching the ultrasonic sensing result signal reflected from the object as the deflip-flop U2. At this time, the microcomputer 105 executes FIG. 6C, sets the S / W timer in step 6i, and calls the real-time clock in step 6j.

In step 6k, check whether the limit value of the transmit on enable flag reaches 1.8 to 2.5ms, and when the limit value is reached, clear the transmit on enable flag in step 6l, and in step 6m. After setting the ultrasonic 40KHz firing time adjustment timer, call the real-time clock in step (6n), go to the distance processing service routine, and call it with a timer routine to process the object signal and process it according to the distance to the object. In this case, the temporal gap is reduced and the detection error is reduced. At this time, compare the out time (24 × 500us / MAX, 210cm), and if it is smaller than the set value, execute it in the process (6D). In step (5g), time is called, which reads the sense flag in the sense flag register in (6o) and checks whether the level is out of bounds when detected in (6p). When out of the corresponding boundary range, the microcomputer 105 turns off the alarm circuit 106 and the LED unit 110, and when the boundary range is within the corresponding boundary range, the boundary range is 0 to 50 cm (6r, 5s, 6t). Check if value = 6 ~ 7), 50 ~ 100cm (timer value = 9 ~ 12), and 100 ~ 210cm (timer value = 13 ~ 23). When there is an object within the corresponding range, the LED unit 110 is controlled to be displayed in the process of (6v, 6w, 6x) by the execution of the process (5h, 5i), and the alarm circuit is processed in the process (6y, 6z, 6a). Control 106 to ring the buzzer PZ. For example, if it is 0 ~ 50cm, turn on lamp # 1 and turn RA3 low to turn on buzzer # 1. In case of 50 ~ 100cm, turn on lamp # 2 (pinno = 7 (low0)), operate with buzzer # 2 on, adjust the firing interval of emission ultrasonic frequency in (7C), and Clear each transmission timer and buzzer counter as shown. That is, the transmission time interval delay time is set in step (7d), the transmission time is set, and (40 = TX enable existing time value) in the steps (7e) to (7g), various timers are cleared. Out timer), transmission on / off timer, reception detection timer, reception detection flag register, buzzer counter register, reception on register, buzzer on / off pulse timer (1, 2, 3, 4) (LED1, 2, 3) It also reloads the RTCC value of the option register. The relationship between the detection distance calculation and the processing range of (6D) is easily understood by a technique using reflection and scattering of ultrasonic waves from an object.

r: Reflection, Z1: Acoustic impedance of near-side medium, Z2: Output impedance, θ1: Angle of incidence, θ2: Output angle, therefore Z ~ = ~ OC, O: Frequency of medium, C: Sound velocity, distance in medium The measuring method is L: distance of the object (m), T: measured time (sec), V: sound velocity (m / sec), and the time when the ultrasonic wave reciprocates to the object.

L = T.V / 2 (m)

If the temperature of sound velocity in air is t (℃), the sound velocity changes according to the temperature, so V = 33.15 + 0.6t (m / sec) (the previous day velocity of sound waves in the air in one plane)

* Sonic speed for temperature change is 15 ℃: 340.5m / s, temperature is 20 ℃: 340.5m / s, temperature is 25 ℃: 340.5m / s, measuring distance: 2%. [When measuring a distance of 3m, if the temperature change is within ℃, the error within + 6cm ~ 6cm (total 12cm) changes.]

Example: If you reflect ultrasound at 15 ° C / 25 ° C and the measured time takes 3ms

L1 (15 ℃) = 0.003 × 340.5 × 1/2 (m / s) = 0.51075m / s = 51cm / s

L2 (25 ℃) = 0.003 × 346.5 × 1/2 (m / s) = 0.51975m / s = 52cm / s

Therefore, as shown above, the error of about 1cm occurs, but it is actually more different than this, so it is stabilized by hardware equipped with sensor, semiconductor, and microcomputer with good temperature compensation. Compensation tables can be created to minimize errors and measure distances to objects with stable characteristics. In addition, when the alarm circuit 106 is described, the alarm sound data output from the microcomputer 105 is output by varying the tones for each of the set steps (minimum 3 to maximum 8) as shown in FIG. When applied to the base of the transistor (NPN) Q1 through the DC blocking capacitor (C3), and through the high-frequency rejection and filter capacitor (C4) and the abnormal operation prevention resistor (R4), the collector and emitter of the transistor (Q1) The piezo buzzer PZ connected between the collector of the transistor Q1 and the first power supply terminal Vcc1 is driven in accordance with the change in resistance therebetween. In this case, the diode D2 connected in parallel with the piezo buzzer PZ is for protecting the transistor Q1 for absorbing back EMF generated during the operation of the piezo buzzer PZ. The LED unit 110 uses light emitting diodes LED1 to LED9 as the sensing distance display unit of the object. It consists of 9 light emitting diodes consisting of 3 X-axis lines and 3 Y-axis lines, and consists of X x Y metrics. The lamp driving circuit 107 composed of the resistors R8 to R10 is controlled by the microcomputer 105. The operation of the rest circuit 104 is performed when the priority voltage is applied to the clear end of the microcomputer 105 while power is charged to the capacitor C10 through the resistor R1 which is the charge route. ) Is lowered to about 0.8V or less GND, and when the charge of the capacitor C10 is completed, the voltage level is changed to be close to the voltage of the second power supply terminal Vcc2, and the microcomputer 105 starts normal operation. . The diode D1 connected in parallel with the resistor R1 connected to the second power supply terminal Vcc2 is for preventing back EMF. The reference clock generating circuit 103 generates a clock frequency, a reference frequency for ultrasonic waves, and a fundamental frequency for generating a warning sound required by the microcomputer 105 by the configuration of the crystal oscillator X1 and the capacitors C1 and C2. Circuit. The capacitors C1 and C2 connected between both ends of the crystal oscillator X1 and GND are for parasitic oscillation prevention and temperature compensation.

The power supply circuit for driving the implementation circuit of the present invention of FIG. 7 includes an overcurrent prevention fuse, a battery polarity matching bridge diode BD1, a spark noise canceling coil L1, a capacitor C11, C12, and C13, and the present invention. It consists of a stabilized integrated circuit (U4) for the second power supply terminal (Vcc2), the input circuit voltage switching terminal, a transistor (Q4), a zener diode (D3), and a resistor (R14). Is as follows. When the power is input to the battery input terminal, even if the polarities of the batteries are changed by the bridge diode BD1, the normal voltage is always applied to the positive connection point of the choke coil L1 and the capacitor C11. The wiring is set to 12V and is set to 24V when the battery voltage is 24V. At this time, if it is 12V, it is directly connected to the input pin of the regulator IC for the second power supply terminal Vcc2, and is converted to 5V and supplied to the circuit. When the battery is 24V, when the emitter voltage of transistor Q4 is changed to 12V by the bias voltage set by zener diode D3 and resistor R14 and is applied to regulator U4, the output is stabilized at 5V and the second power source Supply to the connection point of stage Vcc2. The first power supply terminal Vcc1 for driving the pager buzzer PZ is supplied at a connection point between the positive terminal of the bridge diode BD1 and the choke coil L1. Although the embodiment of the present invention discloses an application example in a vehicle, it should be noted that the present invention may be applied to other various fields for detecting a fixed or moving object without departing from the basic idea of the present invention.

As described above, the present invention installs an ultrasonic transmitter and receiver, but specially designed and manufactured a structure so that the transmitter and receiver modules have a predetermined distance from each other so that one ultrasonic transmitter and receiver can monitor a wide range. It has a parking function that can detect the long-distance and wide range of objects when the vehicle is backed up and maintain the safety distance precisely when the vehicle is backed up by processing the round-trip receiving distance measurement by the concept of time-to-distance. All of them adopt a semiconductor integrated circuit, which improves stability and reliability, and reduces the malfunctioning factor.In addition, since the semiconductor has little characteristic change in temperature change in the amplification circuit and the sensing circuit of the receiver, the transmission ultrasonic frequency is generated by oscillation by the crystal oscillator. There is an advantage that can stabilize the characteristics against temperature fluctuations.

Claims (6)

In the object sensing circuit around the vehicle, the transmitter 109 for transmitting ultrasonic waves to the object around the vehicle, the reference clock generating circuit 103 for providing a reference clock, and the ultrasonic waves transmitted from the transmitter 109 reflected through the object Receiving unit 101 that receives the ultrasonic waves and automatically controls the gain and compensates the signal according to the temperature change of seasons and surroundings, and controls the lighting of the lamp when the reverse gear is operated to reverse the driving vehicle. Controls the driving power supply, receives a reference clock from the reference clock generation circuit 103, divides 1 / n to generate an ultrasonic signal, and receives the transmitted ultrasound of the transmitter 109 from the receiver 101 to measure the reflection time. After determining the distance from the object, control the alarm sound generation and display to distinguish the distance for easy recognition by the driver when it is within a certain range. A comb 105, a reset circuit 104 for initializing the power supply to the microcomputer 105, and a switch SW1 connected to the output terminal RA3 to provide a signal for a functional test. And an alarm circuit 106 for generating an alarm sound distinguished at every distance interval with the object according to the alarm generation control signal generated from the microcomputer 105 whenever the object reaches a predetermined range from the vehicle. LED unit 110 and the micom 105 for displaying a distinction every distance to the object by the control signal generated according to the distance generated from the micom 105 each time the vehicle reaches a predetermined range from the vehicle, and the micom 105 Lamp driving circuit 107 connected to the LED 110 to control driving of the LED unit 110 and the microcomputer 105 to provide an interrupt signal to the microcomputer 105 from an output of the receiver 101. Interrupt Vehicle rear object detection apparatus, characterized by consisting of a control circuit (102). The transmitter 109 is connected to the base of the transistors (Q2, Q3) from the output terminal (RA1) of the microcomputer 105 via a resistor (R5), the emitters of the transistors (Q2, Q3) Vehicle rear object detection device, characterized in that configured to be connected to the transmitting terminal (Tx) by connecting a capacitor (C5) to. 2. The receiving unit (101) according to claim 1, wherein the receiving unit (101) connects a gain control resistor (R11) and a capacitor (C6) in series from a ground terminal (GND), and the resistor (R11) is a receiving signal temperature compensation thermistor in parallel. (TH1) is connected in parallel, a remote control sensing amplifier (U3) for sensing and amplifying the ultrasonic signal input through the receiving terminal (Rx) is connected to the receiving terminal (Rx), and the output terminal of the remote control sensing amplifier (U3) ( out) to connect the pull-up resistor (R13), and to the frequency control stage (FO) connected to the control resistor (R12) for adjusting the intermediate frequency. According to claim 1, LED unit 110 is configured in a matrix form a plurality of light emitting diodes (LED1 ~ LED9) from a plurality of lines on the X-axis and Y-axis from the output ports (RA0 ~ RA7) of the microcomputer 105. Vehicle rear object detection device characterized in that. 2. The apparatus of claim 1, wherein the interrupt control circuit (102) is configured as a flip-flop (U2). The circuit of claim 1, wherein the alarm circuit 106 connects the resistor R3 and the capacitor C3 in series from the output terminal RA0 of the microcomputer 105, and the base of the transistor Q1 from the capacitor C3. And a diode (D1) and a buzzer (PZ) connected in parallel to the collector of the transistor (Q1).