CN105496359A - Portal 24 GHz continuous wave human body life detection instrument - Google Patents

Abstract

The invention discloses a portable 24GHz continuous wave human life detector, which comprises a transmitter and a transmitting antenna connected thereto, a receiver front end and a receiving antenna connected thereto, an AD converter, an analog signal conditioning circuit module before the AD converter, The digital signal processor after the AD converter, the display terminal and the DC/DC power supply module powered by the mobile power supply; the transmitter and the transmitting antenna connected to it, the receiver front end and the receiving antenna connected to it are detected by K-LC2 radar instrument module, the analog signal conditioning circuit module adopts a program-controlled amplifier and a Butterworth filter, the AD converter and the digital signal processor after the AD converter adopt a C8051f350 single-chip microcomputer, and the display terminal is a display terminal with a digital signal processing function ; The DC/DC power supply module is respectively connected with the K-LC2 radar detector module, the analog signal conditioning circuit module and the C8051f350 single-chip microcomputer. The detector is small in size, portable and low in cost.

Description

A Portable 24GHz Continuous Wave Human Life Detector

technical field

The invention relates to a life detector, in particular to a portable 24GHz continuous wave human life detector, which is used for non-contact detection of human life signals.

Background technique

The non-contact human life detector is a detector that uses wireless electromagnetic waves to detect human vital signs. Compared with the traditional contact human life detector, this detector does not need to directly contact the human body such as electrodes to avoid discomfort to the human body, and is especially suitable for long-term monitoring of the vital signs of the elderly and children who do not move around. In addition, using the penetrability of electromagnetic waves, the existence of life can be detected through partition walls, and the detector can also be used for rescue such as firefighting and earthquakes. Therefore, since the 1970s, people have carried out a lot of research on the human body life detector. In order to avoid the serious drop of the detection accuracy caused by the "zero point" problem in the detection process, the detector usually adopts an orthogonal I/Q design. In recent years, in order to make the detection accuracy of the human life detector higher, so that it can be more effectively used in the field of medical care. People's research on hardware system design mainly focuses on three aspects: (1) The frequency of electromagnetic waves emitted by radar develops from low frequency to high frequency: 2.4GHz develops to 5.8GHz, 10Hz, 24GHz, and even 35GHz, because the higher the frequency, the higher the frequency of electromagnetic waves. The shorter the wavelength, the higher the sensitivity of the detector. (2) The ADC resolution is developed from 16bit to 24bit, and the sampling rate adopts the KHz level to collect data. Because the higher the resolution, the higher the signal-to-noise ratio of the receiver. The higher the acquisition rate, the higher the signal quantization signal-to-noise ratio. (3) For ease of use, the system integration of large volume and heavy weight is developing towards high integrated circuits. These higher-sensitivity detectors cooperate with effective signal processing algorithms for heart rate extraction, which will greatly improve the life detection accuracy of the detector.

However, the current portable 24GHz human life detector has the following problems in terms of portability and practicability: (1) The 24GHz transceiver antenna adopts a specially customized method, which is large in size and high in cost. (2) 24bitADC is implemented with a dedicated independent ADC chip or acquisition card such as TexasInstrumentADS1251, which is costly and increases the complexity of integration. (3) The power supply is realized by a 220V transformer or a large-volume lithium battery, which cannot be truly portable and lightweight.

Contents of the invention

In order to solve the above problems, the present invention provides a portable 24GHz continuous wave human life detector, which can be used to detect human life signals without contact, and has the advantages of small size, portability and low cost.

The above-mentioned purpose is achieved through the following technical solutions:

A portable 24GHz continuous wave human life detector, including a transmitter and a transmitting antenna connected to it, a receiver front end and a receiving antenna connected to it, an AD converter, an analog signal conditioning circuit module before the AD converter, and a rear end of the AD converter The digital signal processor, the display terminal and the DC/DC power supply module powered by the mobile power supply; the transmitter transmits the LO signal of the local oscillator to the front end of the receiver, and the front end of the receiver outputs I/Q two-way signals to the analog signal conditioning circuit module, The analog signal conditioning circuit module filters and amplifies the received signal and then divides it into I/Q two-way signal and sends it to the AD converter. The AD converter converts the received analog signal into a digital signal and then divides it into I/Q two-way signal for transmission. To the digital signal processor, finally output to the display terminal display; wherein, the transmitter and the transmitting antenna connected to it, the receiver front end and the receiving antenna connected to it adopt the K-LC2 radar detector module, and the analog signal conditioning circuit The module adopts a program-controlled amplifier and a Butterworth filter, the AD converter and the digital signal processor behind the AD converter adopt a C8051f350 single-chip microcomputer, and the display terminal is a display terminal with a digital signal processing function; the DC/DC power supply modules are respectively It is connected with K-LC2 radar detector module, analog signal conditioning circuit module and C8051f350 single chip microcomputer.

The K-LC2 radar detector module improves the integration of the detector and simplifies the design. It can directly supply +5V power supply, directly down-convert the signal received by the antenna, and output the analog baseband signal. The AD converter and the digital signal processor after the AD converter adopt the C8051f350 single-chip microcomputer, which can meet the AD conversion requirements of the human life detector on the one hand, and on the other hand, can perform preliminary processing on the digital signal after the AD conversion, which is better than using a special high-resolution The high-rate AD converter is simple in design and low in cost. The display terminal with digital signal processing function connected behind the C8051f350 microcontroller can further process and display the digital signal. The display terminal with digital signal processing function is easy to obtain, simplifies the design of the detector, facilitates the improvement of the integration of the detector, and is small in size, portable and low in cost.

Further, the program-controlled amplifier is a 100-fold dual program-controlled amplifier.

Further, the Butterworth filter is a fourth-order Butterworth filter. A fourth-order Butterworth is used to achieve low-pass 30Hz filtering.

Further, the display terminal with digital signal processing function is a mobile phone or a computer.

Further, the C8051f350 single-chip microcomputer sends the preliminarily processed signal to the mobile phone or computer through its serial port or an external serial port to Ethernet module for further signal processing and display.

Further, the serial port-to-Ethernet module is replaced by a serial port-to-wireless Ethernet module. The serial port-to-wireless Ethernet module is used to replace the serial port-to-Ethernet module to facilitate remote transmission. There are a lot of this module on the market, the price is less than 100 yuan.

Further, the K-MC3 radar detector module is used instead of the K-LC2 radar detector module. RFbeam provides a large number of 24GHz radar front-end modules with different beams. In order to improve the gain of the antenna and the sensitivity of the receiver, you can choose other RFBeam radar transceiver front-ends such as K-MC3 instead of K-LC2, because K-MC3 has its own amplifier, which can further Increase the sensitivity of the detector.

Further, the analog signal conditioning circuit module is also provided with a DC filter or an adjustable DC bias circuit. The baseband output signal at the front end of the receiver contains large static clutter. In order to achieve the highest resolution of AD acquisition, a DC filter or an adjustable DC bias circuit should be added to the analog signal conditioning circuit module to make the DC output of the I/Q baseband The bias signal amplitude is at half of the AD internal maximum voltage (2.5V) of the C8051f350.

Beneficial effects of the present invention:

(1) The transmitter, transmitting antenna, receiver front end and receiving antenna are realized by the K-LC2 radar detector module, which can be directly powered by +5V and is only the size of a 1 yuan coin, which improves the system integration and simplifies the system design .

(2) The present invention does not use a special high-resolution AD converter, but directly uses a C8051f350 single-chip microcomputer to realize. The advantage of this single-chip microcomputer is that it has two channels of 24bit sum and difference ADC, and the maximum sampling rate is 1Ksps, which fully meets the ADC requirements of the human life detector. The Rom of the single-chip microcomputer is 8K. After simple processing of the two-way digital signal, it can be directly sent to the mobile phone or computer for further signal processing through the serial port of the single-chip microcomputer or an external serial port-to-Ethernet module, and the breathing and heartbeat frequency of the human body can be extracted. In addition, the single-chip microcomputer is cheap, about 16 yuan a piece.

(3) Due to the rapid development of mobile terminals, various types of mobile power sources have appeared. The present invention can directly use mobile power sources and provide a miniUSB port as a power input to truly realize portability.

Description of drawings

Fig. 1 is the frame diagram of the composition principle of the human life detector provided by the present invention;

Fig. 2 is a display diagram of measurement data of the human life detector provided by the present invention.

detailed description

The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, a portable 24GHz continuous wave human life detector includes a transmitter and a transmitting antenna connected to it, a receiver front end and a receiving antenna connected to it, an AD converter, and an analog signal conditioning circuit before the AD converter Module, digital signal processor after AD converter, display terminal and DC/DC power supply module powered by mobile power supply; the transmitter sends the local oscillator LO signal to the front end of the receiver, and the front end of the receiver outputs I to the analog signal conditioning circuit module /Q two-way signal, the analog signal conditioning circuit module filters and amplifies the received signal and then divides it into I/Q two-way signal and sends it to the AD converter. The AD converter converts the received analog signal into a digital signal and then divides it into I The /Q two-way signal is sent to the digital signal processor, and finally output to the display terminal for display; wherein, the transmitter and the transmitting antenna connected to it, the front end of the receiver and the receiving antenna connected to it adopt the K-LC2 radar detector module, The analog signal conditioning circuit module adopts a one-hundred-fold dual-program amplifier and a fourth-order Butterworth filter, the AD converter and the digital signal processor behind the AD converter adopt a C8051f350 single-chip microcomputer, and the display terminal has a digital signal A display terminal with processing functions, such as a mobile phone or a computer; the DC/DC power supply module is connected to the K-LC2 radar detector module, the analog signal conditioning circuit module and the C8051f350 single-chip microcomputer respectively.

The K-LC2 radar detector module improves the integration of the detector and simplifies the design. It can directly supply +5V power supply, directly down-convert the signal received by the antenna, and output the analog baseband signal. The AD converter and the digital signal processor after the AD converter adopt the C8051f350 single-chip microcomputer, which can meet the AD conversion requirements of the human life detector on the one hand, and on the other hand, can perform preliminary processing on the digital signal after the AD conversion, which is better than using a special high-resolution The high-rate AD converter is simple in design and low in cost. The display terminal with digital signal processing function connected behind the C8051f350 microcontroller can further process and display the digital signal. The C8051f350 single-chip microcomputer sends the preliminarily processed signal to a mobile phone or a computer through its serial port or an external serial port-to-Ethernet module for further signal processing and display. Display terminals with digital signal processing functions such as mobile phones or computers are easy to obtain, which simplifies the design of the detector, facilitates the integration of the detector, and is small in size, portable and low in cost. A low-pass 30Hz filter can be achieved by a fourth-order Butterworth filter.

Fig. 2 is a display diagram of measurement data of the human life detector provided by the present invention. The human body is still 50cm in front of the detector, and the measured two-way human life signals can be seen to have obvious periodicity.

In order to facilitate remote transmission, the serial port to Ethernet module can be used instead of the serial port to Ethernet module. The serial port-to-wireless Ethernet module is used to replace the serial port-to-Ethernet module to facilitate remote transmission. There are a lot of this module on the market, the price is less than 100 yuan.

In order to further improve the sensitivity of the detector, the K-MC3 radar detector module can be used instead of the K-LC2 radar detector module. RFbeam provides a large number of 24GHz radar front-end modules with different beams. In order to improve the gain of the antenna and the sensitivity of the receiver, you can choose other RFBeam radar transceiver front-ends such as K-MC3 instead of K-LC2, because K-MC3 has its own amplifier, which can further Increase the sensitivity of the detector.

In order to improve the resolution of AD acquisition, the analog signal conditioning circuit module may also be provided with a DC filter or an adjustable DC bias circuit. The baseband output signal at the front end of the receiver contains large static clutter. In order to achieve the highest resolution of AD acquisition, a DC filter or an adjustable DC bias circuit should be added to the analog signal conditioning circuit module to make the DC output of the I/Q baseband The bias signal amplitude is at half of the AD maximum voltage (2.5V) of the C8051f350.

In the human life detector provided by the present invention, the transmitter, the transmitting antenna, the front end of the receiver and the receiving antenna are realized by the K-LC2 radar detector module, which improves the system integration and simplifies the system design. The present invention does not adopt a special high-resolution AD converter, but directly adopts a C8051f350 single-chip microcomputer to realize. The advantage of this single-chip microcomputer is that it has two channels of 24bit sum and difference ADC, and the maximum sampling rate is 1Ksps, which fully meets the ADC requirements of the human life detector. The Rom of the single-chip microcomputer is 8K. After simple processing of the two-way digital signal, it can be directly sent to the mobile phone or computer for further signal processing through the serial port of the single-chip microcomputer or an external serial port-to-Ethernet module, and the breathing and heartbeat frequency of the human body can be extracted. In addition, the single-chip microcomputer is cheap, about 16 yuan a piece. In addition, the present invention can directly adopt a mobile power supply, and provide a miniUSB port as a power supply input, so that it is truly portable.

The purpose of the above-mentioned embodiments is to illustrate the substantive content of the present invention, but not to limit the protection scope of the present invention. Those skilled in the art should understand that the technical solution of the present invention can be modified or equivalently replaced without departing from the essence and protection scope of the technical solution of the present invention.

Claims (8)

1. A portable 24GHz continuous wave human life detector, characterized in that: comprise a transmitter and a transmitting antenna connected thereto, a receiver front end and a receiving antenna connected thereto, an AD converter, an analog signal conditioning circuit before the AD converter Module, digital signal processor after AD converter, display terminal and DC/DC power supply module powered by mobile power supply; the transmitter sends the local oscillator LO signal to the front end of the receiver, and the front end of the receiver outputs I to the analog signal conditioning circuit module /Q two-way signal, the analog signal conditioning circuit module filters and amplifies the received signal and then divides it into I/Q two-way signal and sends it to the AD converter. The AD converter converts the received analog signal into a digital signal and then divides it into I The /Q two-way signal is sent to the digital signal processor, and finally output to the display terminal for display; wherein, the transmitter and the transmitting antenna connected to it, the front end of the receiver and the receiving antenna connected to it adopt the K-LC2 radar detector module, The analog signal conditioning circuit module adopts a program-controlled amplifier and a Butterworth filter, and the digital signal processor behind the AD converter and the AD converter adopts a C8051f350 single-chip microcomputer, and the display terminal is a display terminal with a digital signal processing function; The DC/DC power supply module is respectively connected with the K-LC2 radar detector module, the analog signal conditioning circuit module and the C8051f350 single-chip microcomputer. 2. The portable 24GHz continuous wave human life detector according to claim 1, characterized in that: said program-controlled amplifier is a 100-fold dual program-controlled amplifier. 3. The portable 24GHz continuous wave human life detector according to claim 1, characterized in that: the Butterworth filter is a fourth-order Butterworth filter. 4. The portable 24GHz continuous wave human life detector according to claim 1, characterized in that: the display terminal with digital signal processing function is a mobile phone or a computer. 5. The portable 24GHz continuous wave human life detector according to claim 4, characterized in that: the C8051f350 single-chip microcomputer sends the preliminary processed signal to a mobile phone or a computer through its serial port or an external serial port to Ethernet module for further processing. signal processing and display. 6. The portable 24GHz continuous wave human life detector according to claim 5, characterized in that: the serial port-to-Ethernet module is replaced by a serial port-to-wireless Ethernet module. 7. The portable 24GHz continuous wave human life detector according to claim 1, characterized in that: the K-MC3 radar detector module is used instead of the K-LC2 radar detector module. 8. The portable 24GHz continuous wave human life detector according to claim 1, wherein the analog signal conditioning circuit module is also provided with a DC filter or an adjustable DC bias circuit.