CN105699976A - Ultrasonic range finder based on single-chip microcomputer - Google Patents

Abstract

The invention discloses an ultrasonic rangefinder based on a single-chip microcomputer, which comprises a shell and a fixed deck, and the shell is detachably mounted on the fixed deck; a PCB board and a battery are arranged inside the shell, and the PCB board contains Control circuit; the shell is provided with an ultrasonic sending probe, an ultrasonic receiving probe, a temperature sensor, an LCD liquid crystal display, and buttons, and the ultrasonic sending probe, an ultrasonic receiving probe, a temperature sensor, an LCD liquid crystal display, and buttons are all connected with the control circuit connected. The range finder of the invention has the advantages of simple structure, convenient assembly and disassembly, low cost and high precision.

Description

Ultrasonic Range Finder Based on Single Chip Computer

technical field

The invention relates to a range finder, in particular to an ultrasonic range finder based on a single-chip microcomputer.

Background technique

Measuring tools are widely used in architectural decoration, real estate evaluation, mechanical installation, farmland water conservancy, road traffic, mine tunnels, and garden planning, but some of them still use the traditional measuring tool-tape measure. The disadvantage of measuring with a tape measure is that when measuring a higher height, it is necessary to use other auxiliary tools such as a ladder to measure, which increases the workload. Long, need auxiliary tools such as calculator to calculate again, waste manpower and material resources. Other ranging tools in the prior art have complex structures, high manufacturing costs and large volumes.

Contents of the invention

Aiming at the deficiencies in the prior art, the object of the present invention is to provide an ultrasonic rangefinder based on a single-chip microcomputer, which is simple, convenient, fast, accurate and low in cost.

In order to achieve the above object, the technical solution adopted by the present invention is as follows: a single-chip microcomputer-based ultrasonic rangefinder includes a housing and a fixed holder, and the housing is detachably mounted on the fixed holder; the housing is provided with The PCB board and the battery, the PCB board contains a control circuit; the shell is provided with an ultrasonic sending probe, an ultrasonic receiving probe, a temperature sensor, an LCD liquid crystal display, buttons, and the ultrasonic sending probe, an ultrasonic receiving probe, and a temperature sensor , LCD liquid crystal display screen and buttons are all connected with the control circuit.

As a preferred solution, the fixed card seat includes a fixed seat, a snap ring, and a telescopic fixed pin. Buttons are arranged on both sides of the fixed seat; the snap ring is arranged on the upper surface of the fixed seat, and the middle of the snap ring The part has an extended hook portion; the telescopic fixing pin is connected with the button and is arranged on the lower surface of the fixing seat.

As a preferred solution, the control circuit includes a single-chip microcomputer and a reset circuit connected to the single-chip microcomputer, a clock circuit, a button circuit, a buzzer circuit, an ultrasonic sending circuit, an ultrasonic receiving circuit, a temperature acquisition circuit, an LCD display circuit, and a power supply circuit. .

As a preferred solution, the model of the single-chip microcomputer is AT89S52.

As a preferred solution, the model of the ultrasonic sending probe is CSB40T.

As a preferred solution, the model of the ultrasonic receiving probe is CSB40R.

As a preferred solution, the model of the temperature sensor is DS18B20.

As a preferred solution, the model of the LCD liquid crystal display is YB1602.

Compared with the prior art, the beneficial effect of the present invention is that the range finder of the present invention has simple structure, convenient assembly and disassembly, low cost and high precision.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic view of the front structure of the fixed card holder in the present invention;

Fig. 3 is a schematic diagram of the back structure of the fixed card holder in the present invention;

Fig. 4 is the functional block diagram of control circuit of the present invention;

Fig. 5 is the circuit schematic diagram of single-chip microcomputer among the present invention;

Fig. 6 is a schematic diagram of a reset circuit in the present invention;

Fig. 7 is the schematic diagram of the clock circuit in the present invention;

Fig. 8 is a schematic diagram of a button circuit in the present invention;

Fig. 9 is the schematic diagram of the buzzer circuit in the present invention;

Fig. 10 is a schematic diagram of an ultrasonic transmission circuit in the present invention;

Fig. 11 is a schematic diagram of an ultrasonic receiving circuit in the present invention;

Fig. 12 is a schematic diagram of the temperature acquisition circuit in the present invention;

Fig. 13 is the schematic diagram of LCD display circuit among the present invention;

Fig. 14 is a schematic diagram of the power supply circuit in the present invention.

detailed description

The present invention will be further described below in conjunction with specific embodiments. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

Example:

As shown in Figure 1, a kind of ultrasonic range finder based on single-chip microcomputer comprises shell 1, fixed deck 2, and described shell 1 is detachably installed on the fixed deck 2; PCB board and battery are arranged in described shell 1 , the PCB board includes a control circuit; the shell 1 is provided with an ultrasonic sending probe 11, an ultrasonic receiving probe 12, a temperature sensor 13, an LCD display 14, buttons, the ultrasonic sending probe 11, an ultrasonic receiving probe 12 , the temperature sensor 13, the LCD liquid crystal display 14, and the buttons are all connected to the control circuit; the buttons include a start button S2 and a reset button S1.

As shown in Fig. 2 and Fig. 3, the fixed card seat 2 includes a fixed seat 21, a snap ring 22, and a telescopic fixed pin 23, and buttons 24 are arranged on both sides of the fixed seat 21; The upper surface of the seat 21, and the middle part of the snap ring 22 has an extended hook 25; the telescopic fixing pin 23 is connected with the button 24, and is arranged on the lower surface of the fixed seat 21; When the rangefinder is fixed on a non-rigid material object such as wood or plastic stool, the button 24 can be pressed to eject the telescopic fixing pin 23 and press it into the non-rigid material object, and the telescopic fixing pin 23 can be retracted and fixed when not in use. In the seat 21, the rangefinder of the present invention can be installed on the fixed card seat 2 for use, and can also be used alone, which is convenient for disassembly and assembly.

As shown in Figure 4, described control circuit comprises single-chip microcomputer 31 and the reset circuit 32 that is connected with single-chip microcomputer 31, clock circuit 33, button circuit 34, buzzer circuit 35, ultrasonic sending circuit 36, ultrasonic receiving circuit 37, temperature acquisition Circuit 38, LCD display circuit 39, power supply circuit 30.

As shown in Figure 5, the model of the single-chip microcomputer is AT89S52, wherein the P0 port is used to send display signals to the LCD display circuit 39, and P2.0~P2.2 send commands to the LCD display circuit 39 to control the display of the LCD liquid crystal display 14 mode; P2.7 is the data acquisition terminal of the temperature sensor 13, connected to the temperature acquisition circuit 38; P1.0 is connected to the button circuit 34.

As shown in Figure 6, it is the principle diagram of the reset circuit 32. The single-chip microcomputer 31 can realize reset by adding a positive pulse greater than 20ms at the RESET end. It gradually rises, and the potential of RESET drops, so a positive pulse is formed at RESET. When the person presses the reset button S1, the capacitor C6 is quickly discharged through R1. After the reset button S1 pops up, the capacitor C6 is charged again to realize manual reset.

As shown in Figure 7, it is the schematic diagram of the clock circuit 33. When the internal clock circuit 33 of the single-chip microcomputer 31 is used, the XATL1 and XATL2 of the single-chip microcomputer 31 are used to connect the quartz crystal and the fine-tuning capacitor. The crystal can generally be selected from 3M to 24M. C9 and capacitor C10 are selected to be about 30pF, and the crystal oscillator selected in this embodiment is 12MHz, and the capacitor is 33pF.

As shown in Figure 8, it is a schematic diagram of the button circuit 34, and the measurement is started by P1.0 of the single-chip microcomputer 31. When the start button S2 is pressed, P1.0 is at a low level, and the single-chip microcomputer 31 starts by inquiring about a low level. Measure the distance, when the start button S2 is released, P1.0 is high level.

As shown in Figure 9, it is a schematic diagram of the buzzer circuit 35. After a buzzer is used to prompt the user to start the button S2, the single-chip microcomputer 31 starts distance measurement, and a DC voltage of 3-5V is applied to both ends of the buzzer. , just can produce the buzzing sound of 3KHz, and this 3KHz signal is sent to the base of triode Q3 from the P3.

As shown in Figure 10, it is the schematic diagram of described ultrasonic sending circuit 36, and the model of described ultrasonic sending probe is CSB40T; It is high level, and the 2 pins of the ultrasonic sending probe CSB40T after the first level of reverse are low level; when the input signal is low level, on the contrary, the oscillating signal is realized to drive the ultrasonic sending probe CSB40T, as long as the control signal Ultrasonic waves can be generated close to 40KHz.

As shown in Figure 11, it is the principle diagram of the described ultrasonic receiving circuit 37, the model of described ultrasonic receiving probe is CSB40R, use the reception detection chip CX20106A integrated circuit to amplify and filter the signal received by the ultrasonic receiving probe during implementation, its total The amplification gain is 80db, and the pin notes of the receiving and detecting chip CX20106A: pin 1 is the ultrasonic signal input terminal, and the input impedance of this pin is about 40kΩ; RC series network is connected between pin 2 and the ground, which is a component of the negative feedback series network part, changing their values can change the gain and frequency characteristics of the preamplifier, increasing the resistor R4 or reducing the capacitor C4 will increase the amount of negative feedback and decrease the magnification, otherwise the magnification will increase, but the capacitor C4 Changes will affect the frequency characteristics, generally do not need to be changed in actual use, the selected parameters are resistor R4=4.7Ω, capacitor C4=1μF; connect detection capacitor C3 between pin 3 and ground, the capacitance is large for average value detection, and responds instantaneously The sensitivity is low, if the capacity is small, it is peak detection, and the corresponding sensitivity is high in an instant, but the pulse width of the detection output changes greatly, which is easy to cause malfunction. The parameter is 3.3μf; 4 pins are grounded; , used to set the center frequency f0 of the bandpass filter, the larger the resistance, the lower the center frequency; an integral capacitor C2 is connected between pin 6 and ground, the standard value is 330pF, if the capacitor C2 is too large, it will make the detection The distance becomes shorter; pin 7 is the remote control command output terminal, which is an open-collector output mode, so this pin must be connected to a pull-up resistor R7 to the power supply terminal, the resistance value is 22kΩ, and the output of this terminal is high when no signal is received Level, when there is a signal, it will drop; pin 8 is the positive pole of the power supply, and the value is 4.5 ~ 5V.

FIG. 12 is a schematic diagram of the temperature acquisition circuit 38 , the temperature sensor is DS18B20, and R13 in the figure is a pull-up resistor.

FIG. 13 is a schematic diagram of the LCD display circuit 39, and the model of the LCD liquid crystal display is YB1602.

As shown in Figure 14 is the schematic diagram of the power supply circuit 30, the LM7805 is selected to obtain a stable +5V DC voltage, the input voltage (<21V) is regulated by the LM7805 to output +5V voltage, and the IN4007 in the figure is to protect the LM7805 To prevent the reverse polarity of the power supply from damaging the LM7805, the filter capacitor is used in parallel with a 100uF electrolytic capacitor C13 and a 104 ceramic capacitor C14.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention.

Claims (8)

1. an ultrasonic range finder based on a single-chip microcomputer, it is characterized in that: comprise shell, fixed deck, described shell is detachably installed on the fixed deck; Described shell is provided with PCB board and battery, and described PCB board Contains a control circuit; the shell is provided with an ultrasonic sending probe, an ultrasonic receiving probe, a temperature sensor, an LCD liquid crystal display, and buttons, and the ultrasonic sending probe, an ultrasonic receiving probe, a temperature sensor, an LCD liquid crystal display, and buttons are all connected to the connected to the control circuit. 2. a kind of ultrasonic range finder based on single-chip microcomputer according to claim 1, is characterized in that: described fixed deck comprises fixed seat, clasp, retractable fixed pin, and the both sides of described fixed seat are provided with button; The snap ring is arranged on the upper surface of the fixing seat, and the middle part of the snap ring has an extended hook portion; the telescopic fixing pin is connected with the button and is arranged on the lower surface of the fixing seat. 3. A kind of ultrasonic range finder based on single-chip microcomputer according to claim 1, it is characterized in that: described control circuit comprises single-chip microcomputer and the reset circuit that is connected with single-chip microcomputer, clock circuit, button circuit, buzzer circuit, ultrasonic wave Sending circuit, ultrasonic receiving circuit, temperature acquisition circuit, LCD display circuit, power supply circuit. 4. The ultrasonic range finder based on a single-chip microcomputer according to claim 3, characterized in that: the model of the single-chip microcomputer is AT89S52. 5. The ultrasonic range finder based on a single-chip microcomputer according to claim 3, characterized in that: the model of the ultrasonic sending probe is CSB40T. 6. The ultrasonic range finder based on a single-chip microcomputer according to claim 5, characterized in that: the model of the ultrasonic receiving probe is CSB40R. 7. The ultrasonic rangefinder based on a single-chip microcomputer according to claim 3, characterized in that: the model of the temperature sensor is DS18B20. 8. The ultrasonic rangefinder based on a single-chip microcomputer according to claim 3, wherein the model of the LCD liquid crystal display is YB1602.