Laser ranging circuit capable of automatically adjusting measurement distance and working method thereof

Abstract

The invention discloses a laser ranging circuit capable of automatically adjusting a measurement distance and a working method thereof. The laser ranging circuit comprises a direct-current voltage conversion circuit, an impedance adjusting circuit, an enabling control circuit, a high-frequency switching circuit, a main control circuit, a laser transmitting tube and a photosensitive CCD circuit. The direct-current voltage conversion circuit provides stable voltage for the impedance adjusting circuit, and the output end of the impedance adjusting circuit is electrically connected with the positive electrode of the laser transmitting tube; the switch output end of the main control circuit is electrically connected with the input end of the high-frequency switch circuit, and the output end of the high-frequency switch circuit is electrically connected with the negative electrode of the laser transmitting tube; the distance of the detected object detected by the main control circuit is judged so as to regulate and control the impedance adjusting circuit to be switched between a short-distance resistance value mode and a long-distance resistance value mode; in a long-distance resistance value mode and a short-distance resistance value mode, the main control circuit can regulate and control the resistance value of the impedance adjusting circuit according to the intensity of a reflected laser signal received by the photosensitive CCD circuit; the distance of a measured object can be accurately and stably measured in a close-distance resistance mode and a long-distance resistance mode.

Description

Technical Field

[0001] The invention relates to the technical field of laser distance measurement, and in particular to a laser distance measurement circuit capable of automatically adjusting the measurement distance. Background Art

[0002] Since the switching frequency of the D1 laser tube reaches 10M during the distance measurement process, the general constant current chip speed cannot keep up, resulting in unstable power supply of the laser tube, which in turn affects the distance measurement accuracy and signal quality, and the measured distance is seriously deviated and unstable. The laser tube may generate instantaneous current and voltage fluctuations during the switching process, which may cause signal distortion and inaccurate distance measurement results; when the current passing through the laser emission tube in the adjustment circuit increases for long-distance measurement, a single resistor cannot shunt, and excessive current will cause damage to the resistor, resulting in damage to the entire current, and the laser cannot be used for distance measurement. Summary of the invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a laser ranging circuit and a working method thereof for automatically adjusting the measuring distance, wherein the switching between the long-distance mode and the short-distance mode of the laser ranging is realized through an impedance adjustment circuit, and the resistance value of the U1 variable potentiometer can be changed in both the long-distance mode and the short-distance mode, and the resistance value is changed to change the current to realize more stable and accurate distance measurement.

[0004] Technical solution: To achieve the above-mentioned purpose, the present invention provides a laser distance measurement circuit for automatically adjusting the measurement distance, comprising a DC voltage conversion circuit, an impedance adjustment circuit, an enable control circuit, a high-frequency switch circuit, a main control circuit, a laser emitting tube and a photosensitive CCD circuit; the DC voltage conversion circuit provides a stable voltage for the impedance adjustment circuit, and the output end of the impedance adjustment circuit is electrically connected to the positive electrode of the laser emitting tube; the switch output end of the main control circuit is electrically connected to the input end of the high-frequency switch circuit, and the output end of the high-frequency switch circuit is electrically connected to the negative electrode of the laser emitting tube; the control output end of the main control circuit (1) is electrically connected to the input end of the enable control circuit, and the output end of the enable control circuit is electrically connected to the enable end of the impedance adjustment circuit, so as to adjust the impedance adjustment circuit to switch to a short-distance resistance mode or a long-distance resistance mode; the main control circuit obtains the photosensitivity characteristics of the photosensitive CCD circuit; when the impedance adjustment circuit is in the long-distance resistance mode or the short-distance resistance mode, the main control circuit can adjust the resistance value of the U1 variable potentiometer in the impedance adjustment circuit according to the intensity of the reflected laser signal received by the photosensitive CCD circuit.

[0005] Furthermore, the PIN11 and PIN12 terminals of the main control circuit are electrically connected to the PIN8 and PIN9 terminals of the U1 variable potentiometer respectively. The main control circuit obtains the photosensitivity characteristics of the photosensitive CCD circuit to obtain the photosensitivity intensity of the reflected laser signal, and outputs a signal adjusted to a corresponding resistor to the U1 variable potentiometer according to the photosensitivity intensity of the reflected laser signal, thereby adjusting the resistance of the U1 variable potentiometer.

[0006] Furthermore, the enable control circuit includes an IC3 integrated circuit, a C4 capacitor and a C5 capacitor; the VDD terminal of the IC3 integrated circuit is electrically connected to a power supply, one end of the C4 capacitor and one end of the C5 capacitor, and the other end of the C4 capacitor is grounded, and the other end of the C5 capacitor is grounded; the AIN3 terminal, AIN4 terminal, PD1 terminal, PC7 terminal and PC6 terminal of the IC3 integrated circuit are respectively electrically connected to the DATA terminal, nSS terminal, SCLK terminal, MISO terminal and MOSI terminal of the main control circuit; the AIN1 terminal of the IC3 integrated circuit is electrically connected to the EN terminal of the IC2 integrated circuit in the impedance adjustment circuit to control the IC2 integrated circuit to be turned on and off.

[0007] Furthermore, the high-frequency switching circuit includes a Q1 integrated circuit and an R6 resistor; the four D terminals of the Q1 integrated circuit are electrically connected to the negative electrode of the laser emitting tube, and the G terminal of the Q1 integrated circuit is electrically connected to the LEDPP terminal of the main control circuit through the R6 resistor to control the opening and closing of the high frequency of the laser emitting tube.

[0008] Furthermore, the DC voltage conversion circuit includes an IC1 integrated circuit and a C1 capacitor; the FB end of the IC1 integrated circuit is electrically connected to one end of the C1 capacitor and one end of the R2 resistor, and the FB end of the IC1 integrated circuit is grounded through the R1 resistor; the other end of the C1 capacitor is grounded, the other end of the R2 resistor is electrically connected to the SW end of the IC1 integrated circuit through the L1 inductor, and the other end of the R2 resistor is electrically connected to the OUT end of the IC1 integrated circuit; the VIN end of the IC1 integrated circuit is electrically connected to the EN end of the IC1 integrated circuit through the R3 resistor.

[0009] Furthermore, the impedance adjustment circuit also includes an R5 resistor; the OUT end of the IC2 integrated circuit is electrically connected to one end of the R5 resistor, and the other end of the R5 resistor is electrically connected to the positive electrode of the laser emitting tube and the A end of the U1 variable potentiometer; the W end of the U1 variable potentiometer is electrically connected to the IN end of the IC2 integrated circuit; the VDD end of the U1 variable potentiometer is electrically connected to one end of the C9 capacitor, one end of the C8 capacitor and the power supply, and the other ends of the C9 capacitor and the C8 capacitor are grounded.

[0010] Furthermore, the input end of the DC voltage conversion circuit is electrically connected to the power supply through an LB1 filter circuit, and the LB1 filter circuit includes a C2 capacitor and a C3 capacitor; the VIN end of the IC1 integrated circuit is electrically connected to the power supply, one end of the C2 capacitor and one end of the C3 capacitor, and the other ends of the C2 capacitor and the C3 capacitor are grounded.

[0011] Furthermore, the output end of the DC voltage conversion circuit is electrically connected to the input end of the impedance adjustment circuit through the LB2 filter circuit; the LB2 filter circuit includes a C6 capacitor, a C7 capacitor and a TVS1 voltage limiting tube; the OUT end of the IC1 integrated circuit is electrically connected to the IN end of the IC2 integrated circuit in the impedance adjustment circuit, one end of the C6 capacitor, one end of the C7 capacitor and the negative electrode of the TVS1 voltage limiting tube; and the other end of the C6 capacitor, the other end of the C7 capacitor and the positive electrode of the TVS1 voltage limiting tube are grounded.

[0012] Furthermore, a working method of a laser distance measuring circuit for automatically adjusting the measuring distance includes starting the laser distance measuring circuit for automatically adjusting the measuring distance, the DC voltage conversion circuit outputting voltage to the impedance adjustment circuit, powering the laser emitting tube to emit a laser signal; the main control circuit obtaining the light-sensitive intensity of the reflected laser signal according to the light-sensitive CCD circuit, and obtaining the distance of the object to be measured according to the light-sensitive intensity; when the main control circuit detects that the distance of the object to be measured is lower than a threshold value H1, the main control circuit sends a signal to control the enable control circuit to output an enable signal to the impedance adjustment circuit, so that the impedance adjustment circuit switches to a short-distance resistance mode, in which the main control circuit The main control circuit adjusts the light intensity obtained by the photosensitive CCD circuit to the signal of the corresponding resistance to the U1 variable potentiometer, adjusts the resistance value of the U1 variable potentiometer in real time, and measures the object under test; when the main control circuit detects that the distance of the object under test is higher than the threshold value H2, the main control circuit sends a signal to control the enable control circuit to output an enable signal to the impedance adjustment circuit, so that the impedance adjustment circuit switches to the long-distance resistance mode; in the short-distance resistance mode, the main control circuit adjusts the light intensity obtained by the photosensitive CCD circuit to the signal of the corresponding resistance to the U1 variable potentiometer, adjusts the resistance value of the U1 variable potentiometer in real time, and measures the object under test.

[0013] Beneficial effects: The present invention discloses a laser ranging circuit and a working method for automatically adjusting the measuring distance, which realize the switching between the long-distance mode and the short-distance mode of the laser ranging through an impedance adjustment circuit, and the resistance value of the U1 variable potentiometer can be changed in both the long-distance mode and the short-distance mode to change the current, so as to realize more stable and accurate distance measurement; the long-distance and short-distance are switched by switching the damping resistance value using a constant voltage source, and there is no current following problem, and the same constant voltage source is used for the long and short distances, and the difference in test errors between the two is small; when the current passing through the laser emitting tube in the adjustment circuit becomes larger for long-distance measurement, the long-distance resistance mode is realized by setting a resistor in parallel with the U1 variable potentiometer, and even if the current is large, the parallel shunt will still protect the entire circuit, so that the laser ranging is performed safely and stably; the circuit design is simplified, the number of power supplies and related circuit elements are reduced, and the cost is reduced; in the case of load changes, the output voltage can be kept constant, thereby ensuring the normal operation of the system and improving the stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The block diagram of the laser distance measurement circuit for automatically adjusting the measurement distance;

[0015] Figure 2 The specific circuit diagram of the laser ranging circuit for automatically adjusting the measuring distance. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with the accompanying drawings.

[0017] like Figure 1 As shown, a laser distance measurement circuit for automatically adjusting the measured distance includes a DC voltage conversion circuit 2, an impedance adjustment circuit 3, an enable control circuit 5, a high-frequency switch circuit 6, a main control circuit 1, a laser emitting tube 4 and a photosensitive CCD circuit 7; the DC voltage conversion circuit 2 provides a stable voltage for the impedance adjustment circuit 3, and the output end of the impedance adjustment circuit 3 is electrically connected to the positive electrode of the laser emitting tube 4; the switch output end of the main control circuit 1 is electrically connected to the input end of the high-frequency switch circuit 6, and the output end of the high-frequency switch circuit 6 is electrically connected to the negative electrode of the laser emitting tube 4; the control output end of the main control circuit 1 is electrically connected to the enable control circuit 5, and the high-frequency switch circuit 6 is electrically connected to the negative electrode of the laser emitting tube 4. The input end of the circuit 5 and the output end of the enable control circuit 5 are electrically connected to the enable end of the impedance adjustment circuit 3, so as to adjust the impedance adjustment circuit 3 to switch to the short-distance resistance mode or the long-distance resistance mode; the main control circuit 1 obtains the photosensitivity characteristics of the photosensitive CCD circuit 7, and the main control circuit 1 receives the reflected laser signal through the photosensitive CCD circuit 7 to obtain the photosensitivity intensity of the reflected laser signal; when the impedance adjustment circuit 3 is in the long-distance resistance mode or the short-distance resistance mode, the main control circuit 1 can adjust the resistance value of the U1 variable potentiometer 32 in the impedance adjustment circuit 3 according to the intensity of the reflected laser signal received by the photosensitive CCD circuit 7.

[0018] like Figure 2 As shown, the PIN11 and PIN12 terminals of the main control circuit 1 are electrically connected to the PIN8 and PIN9 terminals of the U1 variable potentiometer 32 respectively, the PIN11 and PIN12 terminals of the main control circuit 1 are the 11th and 12th pins of the main control circuit 1, and the PIN8 and PIN9 terminals of the U1 variable potentiometer 32 are the 8th and 9th pins of the U1 variable potentiometer 32; the main control circuit 1 obtains the photosensitivity of the reflected laser signal by acquiring the photosensitivity characteristics of the photosensitive CCD circuit 7, and outputs a signal adjusted to the corresponding resistance to the U1 variable potentiometer 32 according to the photosensitivity of the reflected laser signal, thereby adjusting the resistance of the U1 variable potentiometer 32. The main control circuit 1 is an IC4 integrated circuit, and the photosensitive CCD circuit is integrated in IC4. The IC4 integrated circuit integrates CCD characteristics and can obtain the photosensitivity of the reflected laser signal; the U1 variable potentiometer 32 and the main control circuit 1 are controlled by IIC connecting lines and controlled by AD5258BRMZ1-R7. The internal resistance is dynamically adjusted according to the internal signal amplitude of the CCD characteristics integrated in the main control circuit 1.

[0019] like Figure 2 As shown, the enabling control circuit 5 includes an IC3 integrated circuit 51, a C4 capacitor and a C5 capacitor; the VDD terminal of the IC3 integrated circuit 51 is electrically connected to the power supply, one end of the C4 capacitor and one end of the C5 capacitor, and the other end of the C4 capacitor is grounded, and the other end of the C5 capacitor is grounded; the AIN3 terminal, AIN4 terminal, PD1 terminal, PC7 terminal and PC6 terminal of the IC3 integrated circuit 51 are respectively electrically connected to the DATA terminal, nSS terminal, SCLK terminal, MISO terminal and MOSI terminal of the main control circuit 1; the AIN1 terminal of the IC3 integrated circuit 51 is electrically connected to the EN terminal of the IC2 integrated circuit 31 in the impedance adjustment circuit 3 to control the IC2 integrated circuit 31 to be turned on and off; the GND terminal of the IC3 integrated circuit 51 is grounded, and the SDA terminal and SCL terminal of the IC3 integrated circuit 51 are respectively connected to the data signal and clock signal of the bus. The IC3 integrated circuit 51 and the main control circuit 1 are controlled by means of an SPI connection line.

[0020] like Figure 2 As shown, the high-frequency switch circuit 6 includes a Q1 integrated circuit 61 and an R6 resistor; the four D terminals of the Q1 integrated circuit 61 are electrically connected to the negative electrode of the laser emitting tube 4, and the G terminal of the Q1 integrated circuit 61 is electrically connected to the LEDPP terminal of the main control circuit 1 through the R6 resistor to control the high-frequency on and off of the laser emitting tube 4; the GND terminal of the Q1 integrated circuit 61 is grounded. When the main control circuit 1 needs to measure the distance by laser, the main control circuit 1 sends an LEDPP signal to the high-frequency switch circuit 6, with a frequency of about 10MHz, so that the switching frequency of the D1 laser emitting tube 4 reaches 10M.

[0021] like Figure 2 As shown, the DC voltage conversion circuit 2 includes an IC1 integrated circuit 21 and a C1 capacitor; the FB end of the IC1 integrated circuit 21 is electrically connected to one end of the C1 capacitor and one end of the R2 resistor, and the FB end of the IC1 integrated circuit 21 is grounded through the R1 resistor, and the GND end of the IC1 integrated circuit 21 is grounded; the other end of the C1 capacitor is grounded, the other end of the R2 resistor is electrically connected to the SW end of the IC1 integrated circuit 21 through the L1 inductor, and the other end of the R2 resistor is electrically connected to the OUT end of the IC1 integrated circuit 21; the VIN end of the IC1 integrated circuit 21 is electrically connected to the EN end of the IC1 integrated circuit 21 through the R3 resistor.

[0022] like Figure 2 As shown, the input end of the DC voltage conversion circuit 2 is electrically connected to the power supply through the LB1 filter circuit 8, and the LB1 filter circuit 8 includes a C2 capacitor and a C3 capacitor; the VIN end of the IC1 integrated circuit 21 is electrically connected to the power supply, one end of the C2 capacitor and one end of the C3 capacitor, and the other ends of the C2 capacitor and the C3 capacitor are grounded. The power supply is a 5V power supply for the circuit, and the C2 capacitor and the C3 capacitor of the LB1 filter circuit 8 filter the input voltage. The DC voltage conversion circuit 2 adjusts the resistance values ​​of the R1 resistor and the R2 resistor so that the DC voltage conversion circuit 2 converts the 5V voltage into a suitable voltage value, such as 4.2V, to provide a stable and continuous voltage for the subsequent circuit.

[0023] like Figure 2 As shown, the impedance adjustment circuit 3 also includes and R5 resistor; the OUT end of the IC2 integrated circuit 31 is electrically connected to one end of the R5 resistor, and the other end of the R5 resistor is electrically connected to the positive electrode of the laser emitting tube 4 and the A end of the U1 variable potentiometer 32; the W end of the U1 variable potentiometer 32 is electrically connected to the IN end of the IC2 integrated circuit 31; the VDD end of the U1 variable potentiometer 32 is electrically connected to one end of the C9 capacitor, one end of the C8 capacitor and the power supply, and the other ends of the C9 capacitor and the C8 capacitor are grounded; the GND end of the IC2 integrated circuit 31 is grounded, the GND end of the U1 variable potentiometer is grounded, and the SDA end and the SCL end of the U1 variable potentiometer 32 are respectively connected to the data signal and the clock signal of the bus.

[0024] like Figure 2As shown, the output end of the DC voltage conversion circuit 2 is electrically connected to the input end of the impedance adjustment circuit 3 through the LB2 filter circuit 9; the LB2 filter circuit 9 includes a C6 capacitor, a C7 capacitor and a TVS1 voltage limiting tube 91; the OUT end of the IC1 integrated circuit 21 is electrically connected to the IN end of the IC2 integrated circuit 31 in the impedance adjustment circuit 3, one end of the C6 capacitor, one end of the C7 capacitor and the negative electrode of the TVS1 voltage limiting tube 91; and the other end of the C6 capacitor, the other end of the C7 capacitor and the positive electrode of the TVS1 voltage limiting tube 91 are grounded. Due to power supply fluctuations, the voltage will have a certain deviation. In order to prevent large currents and high voltages from damaging the tube, a TVS voltage limiting tube is added to the output end of IC1 for double protection. Enhance the anti-interference ability and ensure the life of the laser tube; at the same time, the LB2 filter circuit 9 filters the voltage output by the DC voltage conversion circuit to protect the circuit.

[0025] The IC2 integrated circuit 21 is a switch IC integrated circuit, and the R5 resistor is a damping circuit, and the resistance of the R5 resistor is 1Ω. When the IC2 integrated circuit 21 is turned off, the R5 resistor is disconnected, and the impedance adjustment circuit 3 switches to the short-distance resistance mode, and the current only flows through the U1 variable potentiometer 32 to power the D1 laser emission tube; when the IC2 integrated circuit 21 is turned on, the R5 resistor is connected in parallel with the U1 variable potentiometer 32, and the impedance adjustment circuit 3 switches to the long-distance resistance mode, and the current only flows through the R5 resistor and the U1 variable potentiometer 32 to power the D1 laser emission tube.

[0026] A working method of a laser distance measuring circuit for automatically adjusting the measuring distance comprises starting the laser distance measuring circuit for automatically adjusting the measuring distance, a DC voltage conversion circuit 2 outputting a voltage to an impedance adjustment circuit 3, supplying power to a laser emitting tube 4 to emit a laser signal; a main control circuit 1 obtaining the light-sensitive intensity of the reflected laser signal according to a light-sensitive CCD circuit 7, and obtaining the distance of the measured object according to the light-sensitive intensity;

[0027] When the main control circuit 1 detects that the distance of the measured object is lower than the threshold value H1, the main control circuit 1 sends a signal to control the enable control circuit 5 to output an enable signal to the impedance adjustment circuit 3, so that the impedance adjustment circuit 3 switches to the short-distance resistance mode. In the short-distance resistance mode, the main control circuit 1 outputs a signal adjusted to the corresponding resistance through the light-sensitive intensity obtained by the photosensitive CCD circuit 7 to the U1 variable potentiometer 32, and adjusts the resistance value of the U1 variable potentiometer 32 in real time, and measures the measured object;

[0028] When the main control circuit 1 detects that the distance of the object to be measured is higher than the threshold value H2, the main control circuit 1 sends a signal to control the enable control circuit 5 to output an enable signal to the impedance adjustment circuit 3, so that the impedance adjustment circuit 3 switches to the long-distance resistance mode; in the short-distance resistance mode, the main control circuit 1 obtains the light-sensitive intensity output by the photosensitive CCD circuit 7 and adjusts the signal to the corresponding resistance to the U1 variable potentiometer 32, thereby adjusting the resistance value of the U1 variable potentiometer 32 in real time and measuring the object to be measured.

[0029] The power supply is generally a 5V power supply, the IC1 integrated circuit 11 is a voltage converter MP1605, the IC2 integrated circuit 21 is a high-speed load electronic switch GLF1111, the IC3 integrated circuit 31 is a microcontroller unit STM32G031, and the Q1 integrated circuit 51 is a high-speed low-resistance field effect transistor CSD17313.

[0030] Example

[0031] When the laser distance measuring circuit that automatically adjusts the measuring distance is used for distance measurement, when the laser transmitting tube transmits the laser signal to the measured object, the laser signal is reflected to the photosensitive CCD circuit. The main control circuit integrates the characteristics of the photosensitive CCD circuit to obtain the light intensity, and adjusts the resistance mode switching in the impedance adjustment circuit according to the signal amplitude of the light intensity.

[0032] When it is detected that the distance of the measured object is lower than the set threshold value H1, it is necessary to adjust the impedance adjustment circuit to the short-distance resistance mode, the main control circuit 1 notifies the enable control circuit 5 to turn off the IC2 integrated circuit 31, disconnect the R5 resistor, and use the U1 variable potentiometer to power the D1 laser emitting tube 4. The resistance of the U1 variable potentiometer can be adjusted according to the light sensitivity; for example, the initial resistance of the U1 variable potentiometer can be 10Ω, and the voltage drop of D1 is 4V; the current flowing through D1 is approximately (4.2V-4V) / 10Ω=20mA, at this time the brightness of D1 is very low, and the distance within 20cm can be accurately tested; when it is necessary to measure at a short distance, when a higher precision of 1cm or within 1cm is required, the U1 variable potentiometer is 10Ω and it does not meet the accurate measurement; therefore, it is necessary to accurately increase the resistance of the U1 variable potentiometer; as the distance of the measured object gets closer and closer, the light sensitivity will also change accordingly, so the U1 variable potentiometer is adjusted to gradually increase; in the short-distance resistance mode, the resistance of the U1 variable potentiometer automatically changes with the signal amplitude change of the light sensitivity intensity.

[0033] When it is detected that the distance of the measured object is higher than the set threshold value H2, it is necessary to adjust the impedance adjustment circuit to the long-distance resistance mode, the main control circuit notifies the enabling control circuit to turn on the IC2 integrated circuit 31, and the R5 resistor is connected in parallel with the U1 variable potentiometer 32. The U1 variable potentiometer and the R5 resistor are used to simultaneously power the D1 laser emitting tube 4, and the resistance of the U1 variable potentiometer can be adjusted according to the light sensitivity. For example, when the resistance of the U1 variable potentiometer is reduced to 10Ω or other resistance values, the voltage output by the DC voltage conversion circuit remains unchanged, and the resistance of the U1 variable potentiometer is reduced, so that the current passing through the U1 variable potentiometer becomes larger; however, excessive current will cause damage to the U1 variable potentiometer, so a parallel R5 resistor is used for shunting to protect the U1 variable potentiometer. When the U1 variable potentiometer is 10Ω, the R5 resistor is 1Ω, and the parallel resistance is approximately equal to 0.9Ω, and the voltage drop of the D1 laser emitting tube 4 is 4V, the current flowing through D1 is approximately (4.2V-4V) / 0.9Ω=220mA. At this time, the brightness of D1 is improved, and a long distance can be tested; when a longer distance measurement is required, the shunt operation can reduce the resistance of the U1 variable potentiometer, so that the current passing through the resistance adjustment circuit becomes larger to measure a longer distance. In the long-distance resistance mode, the resistance of the U1 variable potentiometer automatically changes with the signal amplitude of the light-sensitive intensity.

[0034] Therefore, in the short-distance resistance mode and the long-distance resistance mode, the resistance of the U1 variable potentiometer is adjusted according to the closeness and distance of the measured object, so that the distance can be accurately and stably measured in both the short-distance resistance mode and the long-distance resistance mode.

[0035] The calculation process of laser measurement distance is as follows:

[0036]

[0037] Where Dtof is the measured distance, c is the speed of light, and f LED is the modulation frequency of the VCSEL light source, DCS0, DCS1, DCS2, and DCS3 are all CCD light intensity values; D OFFSET It is the distance conversion of the delay time of the circuit's light emission and light sensitivity.

[0038] The above is only a description of the preferred embodiments of the present invention. Ordinary technicians in this technical field can make several modifications and optimizations based on the above disclosure without departing from the above basic principles. These improvements and optimizations should be regarded as the understood protection scope of the present invention.

Claims

1. A laser distance measuring circuit for automatically adjusting the measuring distance, characterized in that: The invention comprises a direct current voltage conversion circuit (2), an impedance adjustment circuit (3), an enabling control circuit (5), a high-frequency switch circuit (6), a main control circuit (1), a laser emitting tube (4) and a photosensitive CCD circuit (7); the direct current voltage conversion circuit (2) provides a stable voltage for the impedance adjustment circuit (3), and the output end of the impedance adjustment circuit (3) is electrically connected to the positive electrode of the laser emitting tube (4); the switch output end of the main control circuit (1) is electrically connected to the input end of the high-frequency switch circuit (6), and the output end of the high-frequency switch circuit (6) is electrically connected to the negative electrode of the laser emitting tube (4); the main control circuit (1) ) is electrically connected to the input end of the enable control circuit (5), and the output end of the enable control circuit (5) is electrically connected to the enable end of the impedance adjustment circuit (3), so as to adjust the impedance adjustment circuit (3) to switch to a short-distance resistance mode or a long-distance resistance mode; the main control circuit (1) obtains the photosensitivity characteristics of the photosensitive CCD circuit (7); when the impedance adjustment circuit (3) is in the long-distance resistance mode or the short-distance resistance mode, the main control circuit (1) can adjust the resistance value of the U1 variable potentiometer (32) in the impedance adjustment circuit (3) according to the intensity of the reflected laser signal received by the photosensitive CCD circuit (7).

2. The laser distance measuring circuit for automatically adjusting the measuring distance according to claim 1, characterized in that: The PIN11 and PIN12 terminals of the main control circuit 1 are electrically connected to the PIN8 and PIN9 terminals of the U1 variable potentiometer 32, respectively. The main control circuit (1) obtains the photosensitivity of the reflected laser signal by acquiring the photosensitivity characteristics of the photosensitive CCD circuit (7), and outputs a signal adjusted to a corresponding resistance to the U1 variable potentiometer (32) according to the photosensitivity of the reflected laser signal, thereby adjusting the resistance of the U1 variable potentiometer (32).

3. The laser distance measuring circuit for automatically adjusting the measuring distance according to claim 2, characterized in that: The enabling control circuit (5) comprises an IC3 integrated circuit (51), a C4 capacitor and a C5 capacitor; the VDD terminal of the IC3 integrated circuit (51) is electrically connected to a power supply, one end of the C4 capacitor and one end of the C5 capacitor, and the other end of the C4 capacitor is grounded, and the other end of the C5 capacitor is grounded; the AIN3 terminal, AIN4 terminal, PD1 terminal, PC7 terminal and PC6 terminal of the IC3 integrated circuit (51) are electrically connected to the DATA terminal, nSS terminal, SCLK terminal, MISO terminal and MOSI terminal of the main control circuit (1) respectively; the AIN1 terminal of the IC3 integrated circuit (51) is electrically connected to the EN terminal of the IC2 integrated circuit (31) in the impedance adjustment circuit (3) to control the IC2 integrated circuit (31) to be turned on and off.

4. The laser distance measuring circuit for automatically adjusting the measuring distance according to claim 1, characterized in that: The high-frequency switch circuit (6) comprises a Q1 integrated circuit (61) and an R6 resistor; the four D terminals of the Q1 integrated circuit (61) are all electrically connected to the negative electrode of the laser emitting tube (4), and the G terminal of the Q1 integrated circuit (61) is electrically connected to the LEDPP terminal of the main control circuit (1) through the R6 resistor, so as to control the high-frequency on and off of the laser emitting tube (4).

5. The laser distance measuring circuit for automatically adjusting the measuring distance according to claim 1, characterized in that: The DC voltage conversion circuit (2) comprises an IC1 integrated circuit (21) and a C1 capacitor; an FB terminal of the IC1 integrated circuit (21) is electrically connected to one end of the C1 capacitor and one end of an R2 resistor, and the FB terminal of the IC1 integrated circuit (21) is grounded via the R1 resistor; the other end of the C1 capacitor is grounded, the other end of the R2 resistor is electrically connected to the SW terminal of the IC1 integrated circuit (21) via an L1 inductor, and the other end of the R2 resistor is electrically connected to the OUT terminal of the IC1 integrated circuit (21); and the VIN terminal of the IC1 integrated circuit (21) is electrically connected to the EN terminal of the IC1 integrated circuit (21) via an R3 resistor.

6. The laser distance measuring circuit for automatically adjusting the measuring distance according to claim 5, characterized in that: The impedance adjustment circuit (3) also includes an R5 resistor; the OUT end of the IC2 integrated circuit (31) is electrically connected to one end of the R5 resistor, and the other end of the R5 resistor is electrically connected to the positive electrode of the laser emitting tube (4) and the A end of the U1 variable potentiometer (32); the W end of the U1 variable potentiometer (32) is electrically connected to the IN end of the IC2 integrated circuit (31); the VDD end of the U1 variable potentiometer (32) is electrically connected to one end of the C9 capacitor, one end of the C8 capacitor and a power supply, and the other ends of the C9 capacitor and the C8 capacitor are grounded.

7. The laser distance measuring circuit for automatically adjusting the measuring distance according to claim 6, characterized in that: The input end of the DC voltage conversion circuit (2) is electrically connected to a power supply via an LB1 filter circuit (8), and the LB1 filter circuit (8) comprises a C2 capacitor and a C3 capacitor; the VIN end of the IC1 integrated circuit (21) is electrically connected to the power supply, one end of the C2 capacitor and one end of the C3 capacitor, and the other ends of the C2 capacitor and the C3 capacitor are grounded.

8. The laser distance measuring circuit for automatically adjusting the measuring distance according to claim 7, characterized in that: The output end of the DC voltage conversion circuit (2) is electrically connected to the input end of the impedance adjustment circuit (3) through the LB2 filter circuit (9); the LB2 filter circuit (9) comprises a C6 capacitor, a C7 capacitor and a TVS1 voltage limiting tube (91); the OUT end of the IC1 integrated circuit (21) is electrically connected to the IN end of the IC2 integrated circuit (31) in the impedance adjustment circuit (3), one end of the C6 capacitor, one end of the C7 capacitor and the negative electrode of the TVS1 voltage limiting tube (91); and the other end of the C6 capacitor, the other end of the C7 capacitor and the positive electrode of the TVS1 voltage limiting tube (91) are grounded.

9. The working method of a laser distance measuring circuit for automatically adjusting the measuring distance according to claim 1, characterized in that: The invention comprises a laser distance measuring circuit for starting automatic adjustment of the measured distance, a DC voltage conversion circuit (2) outputting a voltage to an impedance adjustment circuit (3) to power a laser emitting tube (4) to emit a laser signal; a main control circuit (1) obtaining the light-sensitive intensity of the reflected laser signal according to a light-sensitive CCD circuit (7), and obtaining the distance of the object to be measured according to the light-sensitive intensity; when the main control circuit (1) detects that the distance of the object to be measured is lower than a threshold value H1, the main control circuit (1) sends a signal to control an enable control circuit (5) to output an enable signal to the impedance adjustment circuit (3), so that the impedance adjustment circuit (3) switches to a short-distance resistance mode. In the short-distance resistance mode, the main control circuit (1) obtains the light-sensitive CCD circuit (7) to obtain the light-sensitive CCD circuit (7). The light-sensing intensity is outputted to adjust the signal of the corresponding resistance to the U1 variable potentiometer (32), the resistance value of the U1 variable potentiometer (32) is adjusted in real time, and the object to be measured is measured; when the main control circuit (1) detects that the distance of the object to be measured is higher than the threshold value H2, the main control circuit (1) sends a signal to control the enabling control circuit (5) to output an enabling signal to the impedance adjusting circuit (3), so that the impedance adjusting circuit (3) switches to the long-distance resistance mode; in the short-distance resistance mode, the main control circuit (1) obtains the light-sensing intensity through the light-sensitive CCD circuit (7) and outputs the signal of the corresponding resistance to the U1 variable potentiometer (32), the resistance value of the U1 variable potentiometer (32) is adjusted in real time, and the object to be measured is measured.

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