CN202486553U - A light and compact microwave sensor - Google Patents

Abstract

The utility model discloses a light, small and compact microwave inductor, which comprises a printed circuit board and a casing, and the casing is composed of a shell cover and a base that are fastened to each other; the printed circuit board is installed on the shell cover and the base Among them, it includes induction antenna circuit, signal processing circuit, power supply, single-chip microcomputer control circuit and relay output circuit, and also includes induction distance adjustment potentiometer and induction time adjustment potentiometer. By rotating the potentiometer, the induction distance can be realized within 10cm-3m. And the induction time is adjustable within 1s-180s. The utility model adopts a planar antenna, which is integrated on a circuit board together with signal processing and control modules, has small volume, convenient and flexible installation, accurate and sensitive signal detection, large detection range, and adjustable sensing distance and sensing time. Function.

Description

A light and compact microwave sensor

technical field

The utility model relates to a microwave sensor, in particular to a light, small and compact microwave sensor integrating an induction antenna, a signal processing control and an output circuit on one PCB, and belongs to the field of microwave induction communication.

Background technique

At present, microwave sensors have been widely used in security, energy-saving lighting control, automatic control systems, and as induction switches for ATM video control systems. However, the front end of the commonly used microwave induction system on the market mainly adopts a special microwave induction module or a simple loop induction antenna. This commonly used structure implies many manufacturing and use shortcomings. For example, most of the special microwave induction modules use a structure that separates the induction antenna from the signal processing, which is large in size and high in price; The antenna has poor stability, low detection sensitivity, small detection range, and high false alarm rate, which is easy to drift, and the edge point is lower than 1GHz. Therefore, although the loop induction antenna has been launched on the market several years ago, in the current environment where various electric field interferences are increasingly serious, the application range of the loop induction antenna has become smaller and smaller.

Therefore, it is necessary to develop a new type of light and compact microwave sensor, which uses a planar antenna, and is integrated with other modules such as signal processing and control of the sensor on a small PCB, which greatly reduces the size of the microwave sensor. Small size, easy installation and flexible use, and the unique design of the induction antenna makes its signal detection more accurate and sensitive, expanding the detection range of the sensor, and has the function of adjustable sensing distance and sensing time.

Contents of the invention

Aiming at the problems of the prior art, the utility model provides a planar antenna, which is integrated on a circuit board together with signal processing and control modules, has small volume, convenient and flexible installation, accurate and sensitive signal detection, and a large detection range. , and has a light and compact microwave sensor with adjustable sensing distance and sensing time.

In order to solve the above technical problems, the utility model is achieved through the following technical solutions:

The light and compact microwave sensor includes a printed circuit board and a housing, the housing is composed of a shell cover and a base that are fastened to each other; the printed circuit board is installed between the shell cover and the base , including an induction antenna circuit, a signal processing circuit, a power supply, a single-chip microcomputer control circuit and a relay output circuit, wherein the induction antenna circuit, the signal processing circuit, the power supply, the single-chip microcomputer control circuit and the relay output circuit are integrated and embedded on a printed circuit board.

Further, the power supply is respectively connected to the induction antenna circuit, signal processing circuit, single-chip microcomputer control circuit and relay output circuit, the output end of the induction antenna circuit is connected to the input end of the signal processing circuit, and the signal processing circuit The output terminal of the circuit is connected with the control circuit of the single-chip microcomputer, and the output circuit of the relay is connected with the control circuit of the single-chip microcomputer.

Further, the induction antenna circuit is composed of a microwave oscillator composed of a loop antenna and a microwave triode, the operating frequency is 2.4GHz, and the loop antenna adopts a planar embedded PCB miniature loop antenna.

Further, the signal processing circuit is composed of an input signal control circuit, a low-pass filter circuit, a primary signal amplifying circuit and a secondary signal amplifying circuit connected in sequence, and each circuit adopts an operational amplifier LM324/S0.

Further, the single-chip microcomputer control circuit includes a single-chip microcomputer, a reset circuit, an oscillation circuit, a sensing distance adjustment potentiometer and a sensing time adjustment potentiometer, and the single-chip microcomputer adopts a microwave special microprocessor ATtiny13A with a built-in 8-bit precision AD module.

Furthermore, the relay output circuit includes a relay, a control triode and a four-wire terminal. Relays use reed relays.

Furthermore, the casing is made of plastic material.

Furthermore, the size of the shell is 53mm in length, 4mm in height and 13.6mm in width.

Further, the cover is provided with four round holes, two of which are facing the sensing distance adjustment potentiometer and the sensing time adjustment potentiometer respectively, and the other two round holes are respectively facing the printed circuit There are two LED indicators on the board.

Furthermore, by rotating the sensing distance adjusting potentiometer and sensing time adjusting potentiometer, the sensing distance can be adjusted within 10cm-3m and the sensing time can be adjusted within 1s-180s.

The working principle of a light, small and compact microwave sensor described in the utility model is: the induction antenna circuit transmits microwaves and receives echoes reflected by the movement of the human body through the internal microwave oscillator through the embedded PCB board miniature loop antenna. , After being mixed with the microwave triode, a weak signal is detected by the beat. The signal is detected, amplified, filtered, multi-compared and delayed by the signal processing circuit, and then output to the single-chip microcomputer for analog-to-digital conversion. Conduction to control the relay output switch signal, and light up the LED indicator light at the same time.

The utility model has the advantages of providing a light, small and compact microwave sensor, which adopts a planar antenna and is integrated on a circuit board together with signal processing and control modules, which is small in size and convenient and flexible in installation; It is sensitive, has a large detection range, and has the function of adjustable sensing distance and sensing time.

Description of drawings

Fig. 1 is a schematic block diagram of a light, small and compact microwave sensor described in the present invention.

The description marks in the accompanying drawings are as follows: 1. Printed circuit board; 11. Inductive antenna circuit; 111. Loop antenna; 112. Microwave triode; 12. Signal processing circuit; 121. Input signal control circuit; 122. Low-pass filter circuit; 123. Primary signal amplification circuit; 124. Secondary signal amplification circuit; 13. Power supply; 14. Single-chip microcomputer control circuit; 141. Single-chip microcomputer; 142. Reset circuit; 143. Oscillating circuit; 144. Sensing distance adjustment potentiometer; 145. Induction Time adjustment potentiometer; 15, relay output circuit; 151, relay; 152, control triode; 153, four-wire terminal.

Detailed ways

As shown in accompanying drawing 1, a kind of principle block schematic diagram of small and light compact microwave inductor, comprises induction antenna circuit 11, signal processing circuit 12, power supply 13, single-chip microcomputer control circuit 14 and relay output circuit 15, described power supply 13 Connect with described induction antenna circuit 11, signal processing circuit 12, single-chip microcomputer control circuit 14 and relay output circuit 15 respectively, supply power for each module, the output end of described induction antenna circuit 11 is connected with the input end of described signal processing circuit 12 , the output end of the signal processing circuit 12 is connected to the single-chip microcomputer control circuit 14 , and the relay output circuit 15 is connected to the single-chip microcomputer control circuit 14 . The induction antenna circuit 11 is composed of a microwave oscillator composed of a loop antenna 111 and a microwave triode 112, and the working frequency is 2.4 GHz. The signal processing circuit 12 is composed of an input signal control circuit 121 , a low-pass filter circuit 122 , a primary signal amplifying circuit 123 and a secondary signal amplifying circuit 124 connected in sequence. Described single-chip microcomputer control circuit 14 packs single-chip microcomputer 141, reset circuit 142, oscillation circuit 143, sensing distance adjustment potentiometer 144 and sensing time adjustment potentiometer 145; Described reset circuit 142 is connected with described single-chip microcomputer 141 with oscillation circuit 143, makes single-chip microcomputer 141 is working normally, the sensing distance adjusting potentiometer 144 and sensing time adjusting potentiometer 145 are connected to the single chip microcomputer 141 and input as manual adjustment signals. The relay output circuit 15 includes a relay 151, a control triode 152 and a four-wire terminal 153; the base of the control triode 152 is connected to the single-chip microcomputer 141, the collector is connected to the relay 151, and the relay 151 is connected to the four-wire terminal. The two signal lines of the line terminal 153 are connected.

The induction antenna circuit 11, the signal processing circuit 12, the power supply 13, the single-chip microcomputer control circuit 14 and the relay output circuit 15 are integrated on a printed circuit board 1, and are installed between the interlocking shell cover and the base. The shell cover is provided with four circular holes, two of which are respectively facing the sensing distance adjustment potentiometer 144 and the sensing time adjustment potentiometer 145, and the other two are respectively facing the printed circuit board with two LED indicators. The shell composed of the shell cover and the base is made of plastic material and measures 53mmx4mmx13.6mm.

The external power supply inputs 12V DC power to the system through the power line and ground line of the four-wire terminal 153, and converts it into 5V through the power supply 13 to supply power to each module. The induction antenna circuit 11 emits microwaves from the internal microwave oscillator through the embedded PCB miniature loop antenna 111, and generates an elliptical space microwave alert area with an adjustable radius of 10cm to 3m along the axis of the loop antenna 111. At the same time, the echo reflected by the movement of the human body is received. When the human body is active, the reflected echo and the original microwave field or frequency emitted by the loop antenna 111 interfere and change. According to the Doppler effect, the PN junction of the microwave triode 112 will be After the original microwave is mixed with the echo, the beat is detected to obtain a weak frequency shift signal, that is, the movement signal of the human body is detected. The mobile signal is transmitted to the signal processing circuit 12, and the signal is detected, filtered, amplified, The amplified moving signal suitable for the input range of the single-chip microcomputer 141 is obtained after multiple comparisons and delay processing. The single-chip microcomputer 141 performs analog-to-digital conversion on the amplified mobile signal, removes the interference signal with too small amplitude, and only converts the frequency-shifted signal with a certain intensity into equal-amplitude pulses with different widths. Only a single signal with sufficient width, such as the movement signal of a human body, a vehicle, etc., or a movement signal with 2 to 3 narrow pulses within two seconds, such as a movement signal generated by preventing people from walking in the border area for 2 to 3 steps, can be considered effective by the single chip microcomputer 141 signal of. If it is a weaker interference signal such as small-sized animals moving around, long-distance trees shaking, high-frequency communication signals, long-distance lightning and interference signals generated by household appliances switching, the single-chip microcomputer 141 will recognize it as an invalid signal. Once the effective signal of the movement of the real large object is recognized, the single-chip microcomputer 141 generates a delay control signal, and outputs a high level to the relay output circuit 15, so that the control transistor 152 is turned on, thereby controlling the relay 151 to output the switch signal. The switch signal is output to the external device through the two signal lines of the four-wire terminal 153, and the single-chip microcomputer 141 lights up the LED indicator light at the same time, indicating that a valid signal is detected. By rotating the sensing distance adjustment potentiometer 144 and the sensing time adjustment potentiometer 145, the sensing distance can be adjusted within 10cm-3m and the sensing time can be adjusted within 1s-180s. When rotating clockwise, the sensing distance increases, the sensing time shortens, and the sensitivity increases .

This light and compact microwave sensor uses ATtiny13A, a single-chip microcomputer dedicated to microwave, which is a high-performance, low-power 8-bit AVR microprocessor with a clock frequency of 20MHz. When power is applied for the first time, the system will be locked for 17 seconds, during which the initialization of the microcontroller is completed and the electric field is established. At this time, the LED indicator lights up for 17 seconds and then goes out, and the system automatically enters the detection state. When a valid signal is detected, there will be a signal output for 8 seconds, and the LED indicator light is on to indicate the detection status.

Apparently, the above-mentioned embodiment is not a limitation of the present utility model, and there are many other variations of the above-mentioned light, small and compact microwave sensor. Although the utility model has been discussed in detail in conjunction with the above examples, it should be understood that: some similarities and alternatives that can be obviously thought of by professionals in the industry all fall within the scope of protection defined by the claims of the utility model.

Claims (9)

1. A light and small compact microwave inductor, comprising a printed circuit board (1) and a housing, characterized in that the housing is made of a shell cover and a base that are fastened together; the printed circuit board (1) is installed Between the shell cover and the base, an induction antenna circuit (11), a signal processing circuit (12), a power supply (13), a single-chip microcomputer control circuit (14) and a relay output circuit (15) are included, and the induction antenna circuit (11) and the signal processing circuit, the power supply (13), the single-chip microcomputer control circuit (14) and the relay output circuit (15) are integrated and embedded on the printed circuit board (1). 2. The light, small and compact microwave inductor according to claim 1, characterized in that, the power supply (13) is connected to the induction antenna circuit (11), the signal processing circuit (12), the single-chip microcomputer control circuit (14) respectively. ) is connected with the relay output circuit (15), the output end of the induction antenna circuit (11) is connected with the input end of the signal processing circuit (12), and the output end of the signal processing circuit (12) is connected with the single chip microcomputer The control circuit (14) is connected, and the relay output circuit (15) is connected with the single-chip microcomputer control circuit (14). 3. The light, small and compact microwave inductor according to claim 2, characterized in that, the induction antenna circuit (11) is composed of a microwave oscillator composed of a loop antenna (111) and a microwave triode (112), and works The frequency is 2.4GHz. 4. The light and small compact microwave inductor according to claim 3, characterized in that, the signal processing circuit (12) is composed of an input signal control circuit (121), a low-pass filter circuit (122), a primary signal amplifying The circuit (123) and the secondary signal amplifying circuit (124) are sequentially connected to form. 5. The light, small and compact microwave sensor according to claim 4, characterized in that, the single-chip microcomputer control circuit (14) comprises a single-chip microcomputer (141), a reset circuit (142), an oscillation circuit (143), an induction distance adjustment A potentiometer (144) and a sensing time adjustment potentiometer (145). 6. The light, small and compact microwave inductor according to claim 5, characterized in that, the relay output circuit (15) comprises a relay (151), a control triode (152) and a four-wire terminal (153). 7. The light, small and compact microwave inductor according to claim 6, wherein the housing is made of plastic material. 8. The light, small and compact microwave inductor according to claim 7, wherein the length of the housing is 53mm, the height is 4mm, and the width is 13.6mm. 9. The light, small and compact microwave sensor according to claim 8, characterized in that four round holes are arranged on the cover, two of which are respectively facing the sensing distance adjustment potentiometer (144) and the sensing time adjustment potentiometer (145), and the other two round holes are respectively facing the two LED indicator lights that are provided on the printed circuit board (1).

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