WO2014139354A1

WO2014139354A1 - Oximeter based on audio interface communication

Info

Publication number: WO2014139354A1
Application number: PCT/CN2014/072299
Authority: WO
Inventors: 林祝发
Original assignee: Lin Zhufa
Priority date: 2013-03-12
Filing date: 2014-02-20
Publication date: 2014-09-18
Also published as: CN203153748U

Abstract

An oximeter based on audio interface communication comprises a power supply module, a sensor control module, a sensor, a sensor signal processing module and a physical hardware of a standard audio interface; a left sound channel signal transmission line, a right sound channel signal transmission line and a microphone signal transmission line of the audio interface perform a power supply transmission, a control signal input and a collection signal output respectively; a control signal input end of the sensor control module is connected with a control signal input circuit of the audio interface; an input end of the power supply module is connected with a power supply transmission line of the audio interface; an output end of the sensor signal processing module is connected with a collection signal output line of the audio interface; a control signal output end of the sensor control module is connected with a control signal input end of the sensor; a signal output end of the sensor is connected with an input end of the sensor signal processing module.

Description

Oximeter based on audio port communication

The invention belongs to the field of personal medical applications, in particular to an oximeter based on audio port communication based on an audio port. Background technique

At present, with the development of society and the improvement of living standards, people are paying more and more attention to their own health. There are many personal medical products based on vital signs collection equipment, such as portable oximeters, blood glucose meters, fetal heart rate monitors and ECG and so on. The current personal medical products are mainly composed of data acquisition modules, calculation modules, display modules and power modules. The main disadvantages include: First, the cost is high. Second, it is bulky; in addition, lacks data storage and analysis capabilities; and, lack of remote data transfer capabilities. At the same time, mobile devices such as smartphones are becoming more and more popular, and mobile devices have strong computing and display capabilities, as well as power supply, data storage analysis and remote transmission. Summary of the invention

In order to solve the above-mentioned deficiencies of the existing personal medical products, the present invention provides a method for providing personal medical products based on an audio port, and proposes an oximeter based on audio port communication, thereby reducing product cost, reducing product volume, and providing data storage. Analysis and remote transfer capabilities.

In order to achieve the above object, the present invention is based on a method for designing a personal medical product based on an audio port, and is designed to utilize a universal mobile terminal (such as a smart phone, a PDA, a portable computer, etc.) and a vital sign collecting device (may be The existing vital signs collection device is modified, the mobile terminal supplies power to the acquisition device, and drives the acquisition device to collect vital signs, and then receives signals of vital signs and performs calculation, display, data storage, analysis and remote transmission. deal with;

The physical hardware of the standard audio interface is added to the collecting device, and the data signal output terminal, the control signal input terminal and the power input terminal of the collecting device are respectively connected to the terminal terminals of the standard audio port; the collecting device and the mobile terminal pass the standard audio port. For physical connection, the left channel signal transmission line, the right channel signal transmission line and the microphone signal transmission line of the audio port respectively undertake power transmission and signal transmission.

Based on the above design ideas, the specific technical solutions of the method are as follows: The mobile terminal carries audio port hardware and application software, and the application software includes a power driving module, a sensing driving module, a sampling filtering module, a computing module, a data storage module, a data analysis module, a display module, and a remote communication module;

Step one is power supply:

The power driving module of the mobile terminal outputs a sine wave of a certain frequency to the collecting device through the left or right channel of the sound card of the mobile terminal, the sine wave has an audio file corresponding to the sine wave frequency; the power module in the collecting device will sine wave Provide stable power output after processing;

Step 2 is the collection work control of the collection device:

The square wave is generated by the sensing driving module of the mobile terminal, and the square wave has an audio file corresponding to the square wave; the square wave is transmitted to the control signal input end of the collecting device through a channel different from the output of the power driving module;

Step 3 is the collection of vital signs data signals:

The control module of the acquisition device utilizes the rising and falling edges of the square wave to control the acquisition; the fourth step is the processing of the vital sign data signal:

The vital sign data signal collected by the collecting device is sent to the input end of the microphone signal of the mobile terminal through the microphone signal transmission line;

Step 5 is the sampling filtering of the vital sign data signal:

The data signal from the microphone signal transmission line is sampled by the sampling and filtering module of the mobile terminal to obtain a desired signal;

Step six is numerical calculation:

The data signal is calculated by the calculation module of the mobile terminal to obtain a value reflecting the vital signs; Step 7 is data storage:

Data calculated by the data storage module of the mobile terminal is stored;

Step 8 is data analysis:

The data analysis module of the mobile terminal first performs data statistics on the historical data in the data storage module, analyzes the statistical data, and then sends the analysis result to the storage space of the mobile terminal through the storage module;

Step 9 is the data display:

The data is displayed by the data display module of the mobile terminal to the storage space of the mobile terminal, and the currently collected real-time data is displayed on the screen of the mobile terminal, and the result of the data analysis is displayed on the screen in a report or a graphic manner; Step 10 is remote data transfer:

The remote communication module of the mobile terminal is connected to the Internet by using the gprs module, the 3G module or the wifi module of the mobile terminal, and transmits the collected data to the remote server in real time or in batches.

As a further improvement, in the first step, the processing process of the power module in the collecting device is: first, the sine wave is boosted by the step-up transformer, then the FET is rectified, and finally stabilized by the blocking diode and the filter capacitor to stabilize Power output, powering the acquisition device;

The dead zone voltage drop of the rectifier circuit in the low voltage system is a key issue for the power module. If a low voltage diode is used in the rectification process, it is found in the actual measurement that most of the power in the rectification has been lost, and only a small part is transmitted to the load. If FETs are used instead of diodes, synchronous rectification is often used to reduce losses.

In the step 5, the data signal from the microphone signal transmission line is sampled by the sampling and filtering module of the mobile terminal, and the steps are as follows:

First, the analog signal of the vital sign data input from the microphone channel is sampled at a certain sampling rate; then the DC component of the sampling result is extracted, and an IIR filter is used to track the DC component; and then subtracted from the analog signal of the input vital sign data. The DC component is obtained by the DC component; a low-pass FIR filter with a 50dB attenuation is used to remove the ambient noise above 50Hz in the AC component by using a frequency of 6Hz and 50Hz and above; then the AC component signal is used for subsequent processing. signal of.

In the seventh step, the data storage module stored by the data storage module of the mobile terminal is: if the measured values are the same within a period of time, a record of attributes such as start time, end time, number of measurements, and measured value will be used. To store.

Specific to the utility model:

An oximeter based on audio port communication, characterized by comprising physical components of a power module, a sensor control module, a sensor, a sensor signal processing module and a standard audio interface;

The left channel signal transmission line, the right channel signal transmission line and the microphone signal transmission line of the audio interface respectively undertake power transmission, control signal input and acquisition signal output;

The control signal input end of the sensor control module is connected to the control signal input line of the audio interface; the input end of the power module is connected to the power transmission line of the audio interface;

The output end of the sensor signal processing module is connected to the acquisition signal output line of the audio interface; the control signal output end of the sensor control module is connected to the control signal input end of the sensor; and the signal output end of the sensor is connected to the input end of the sensor signal processing module.

The power module includes a step-up transformer, a FET rectifying circuit, a blocking diode, and a filter capacitor; The primary side of the step-up transformer is the input end of the power module; the secondary side of the step-up transformer is connected to the input end of the FET rectifier circuit; the output end of the FET rectifier circuit is connected to the input terminal of the 电路-shaped circuit formed by the blocking diode and the filter capacitor The output of the Π-shaped circuit is the output of the power module.

The sensor control module and the sensor signal processing module are microprocessors or analog circuits.

The sensor comprises a PIN diode, a red LED and an infrared LED; the PIN diode receives light from the red LED and the infrared LED; one end of the PIN diode is connected to the power source, that is, the output end of the sensor;

1. The sensor control module and the sensor signal processing module are microprocessors: the control signal output end of the microprocessor is respectively connected to drive the red LED and the infrared light LED through the driving circuit; meanwhile, the microprocessor acts as a sensor signal processing module, the sensor The output is connected to the signal input of the microprocessor;

Or,

Second, the sensor control module is an analog circuit, which includes:

a) a 1-bit binary counter consisting of a D flip-flop and an inverter; the clock signal input of the D flip-flop is connected to the control signal input line of the audio interface, and the output of the D flip-flop is connected to the two input terminals of the inverter; The anodes of the light LED and the infrared LED are respectively connected to the input end and the output end of the inverter; the D end of the D flip-flop is connected to the output end of the inverter;

b) a voltage-controlled constant current circuit composed of an operational amplifier and a three-stage tube; a high-level input terminal of the operational amplifier is connected to a control signal input line of the audio interface; an output terminal of the operational amplifier is connected to a base of the triode, and a collector connection of the triode The cathode of the red LED and the infrared LED; the low level input of the operational amplifier is connected to the emitter of the triode;

The sensor signal processing module is an analog circuit, and the other end of one end of the PIN diode is connected to the input end of the amplifying circuit, and the output end of the amplifying circuit is connected to the collecting signal output line of the audio interface, and the amplifying circuit is used as a sensor signal processing module.

The microprocessor output also includes a blood oxygen output. Since the arithmetic function of the microprocessing can satisfy the calculation of the blood oxygen signal > blood oxygen value, the calculation can be completed in the oximeter.

The power module further includes a farad capacitor, and the farad capacitor is connected in parallel with the dome circuit. The reason for using the farad capacitor is to better meet the power requirement of the acquisition device, and charge the farad capacitor in the working gap of the component with a large power such as LED. When the LED is working, the power output is performed by the farad capacitor and the dome circuit together. , the entire acquisition device is in a good power supply state. DRAWINGS

1 is a schematic structural diagram of a blood oxygen vital sign measurement system based on an audio interface according to an embodiment of the present invention;

2 is a structural block diagram of a blood oxygen vital sign measuring system according to an embodiment of the present invention;

3 is a basic flow chart of a blood oxygen vital sign measuring system according to an embodiment of the present invention; FIG. 4 is a circuit schematic diagram of a power module of a blood oxygen vital sign measuring system according to an embodiment of the present invention;

5 is a schematic diagram of an LED control module circuit of a blood oxygen vital sign measuring system according to an embodiment of the present invention;

Fig. 6 is a schematic circuit diagram of a PIN signal processing module of a blood oxygen vital sign measuring system according to an embodiment of the present invention. detailed description

The design idea of the utility model is a method for designing a personal medical product based on an audio port. The universal mobile terminal and the vital sign collecting device are used to supply power to the collecting device by the mobile terminal, and the collecting device is driven to collect the vital sign signal, and then Receiving the signal of vital signs and performing subsequent processing; adding physical hardware of the standard audio interface to the collecting device, and connecting the data signal output terminal, the control signal input terminal and the power input terminal of the collecting device to the terminal of the standard audio port respectively The power of the output audio signal of the mobile terminal satisfies the working power requirement of the collecting device, so that the mobile terminal supplies power to the collecting device; the collecting device and the mobile terminal are physically connected through the standard audio port, and the left channel signal transmission line of the audio port, right The channel signal transmission line and the microphone signal transmission line respectively perform power transmission and signal transmission.

The subsequent processing by the mobile terminal after receiving the signal of the vital signs includes calculation, display, data storage, analysis and remote transmission processing of the signals of the vital signs.

The collection device includes a power module, a sensor control module, a sensor, and a sensor signal processing module. The mobile terminal includes an audio port hardware and application software, and the application software includes a power driving module, a sensing driving module, a sampling filtering module, and a calculation. a module, a data storage module, a data analysis module, a display module, and a remote communication module;

Step one is power supply:

The power source driving module of the mobile terminal passes the left or right channel of the sound card of the mobile terminal to the collecting device Outputting a wave of a certain frequency, the signal wave having an audio file corresponding to the frequency; the power module in the acquisition device processes the signal wave to provide a stable power output;

Step 2 is the collection work control of the collection device:

Mode 1 (analog signal mode): The control signal is generated by the sensing driver module of the mobile terminal, the control signal is a square wave, the square wave has an audio file corresponding to the square wave; the square wave outputs a sound different from the power driving module The channel is transmitted to the control signal input end of the acquisition device;

Or, mode 2 (ie, digital signal mode): The sensing driver module of the mobile terminal transmits the control command by using serial communication mode, and its function is equivalent to the control signal in mode 1, and in the digital circuit, the term "command" is generally used; The case of complex control refers to, for example, the need for information communication)

Step 3 is the collection of vital signs data signals:

Corresponding to the method of step 2, the sensor control module of the acquisition device uses the rising edge or the falling edge of the square wave to control the sensor operation;

Corresponding to the second method of step 2, the serial communication is used to receive the control command, and the microprocessor is used to control the operation of the sensor;

Step 4 is the processing of vital signs data signals:

The vital sign signal collected by the sensor is processed by the sensor signal processing module of the collecting device, and then sent to the input end of the microphone signal of the mobile terminal through the microphone signal transmission line;

Step 5 is the sampling filtering of the vital sign data signal:

The data signal from the microphone signal transmission line is processed by the sampling and filtering module of the mobile terminal to obtain a desired signal;

Step six is numerical calculation:

Data calculated by the data storage module of the mobile terminal is stored;

Step 8 is data analysis:

Step 9 is the data display:

Data is taken out from the data display module of the mobile terminal to the storage space of the mobile terminal, and the currently collected data is collected. Real-time data is displayed on the screen of the mobile terminal, and the result of the data analysis is displayed on the screen in a report or graphic manner;

Step 10 is remote data transfer:

The signal wave in the first step is a sine wave or a square wave.

In the fourth step, corresponding to the two methods in the second step and the third step, the signal processing has two modes: a) corresponding mode 1: after the analog signal processing, the analog signal is directly transmitted to the mobile terminal; b) the corresponding mode 2: Converted to a digital signal by a microprocessor and transmits the digital signal to the mobile terminal.

c) Corresponding mode 2: Converted to digital signal by microprocessor, and calculated and transmitted to the mobile terminal. At this point, the filtering and numerical calculations in the processor of the mobile terminal are moved to the acquisition device.

In the first step, the processing process of the power module in the collecting device is: first, the sine wave or the square wave is boosted by the step-up transformer, then the FET is rectified, and finally, the stabilized power is realized after being stabilized by the blocking diode and the filter capacitor. Output, powering the acquisition unit.

First, the signal of the vital sign data input from the microphone channel is sampled at a certain sampling rate; then the signal processing is performed, where the signal processing is digitally filtered by using an IIR filter and/or an FIR filter;

For extracting the DC component and the AC component of the sampling result, an IIR filter is used to track the DC component; then the DC component is subtracted from the analog signal of the input vital sign data to obtain an AC component; for bandpass filtering the signal, Bandpass FIR filter;

For the case 2 in step 2, a complex algorithm such as Fourier transform or wavelet transform can be used for processing.

An oximeter based on audio port communication, comprising a power module, a sensor control module, a sensor, The physical hardware of the sensor signal processing module and the standard audio interface;

The power module includes a step-up transformer, a FET rectifier circuit, a blocking diode, and a filter capacitor; a primary side of the step-up transformer is an input end of the power module; a secondary side of the step-up transformer is connected to an input end of the FET rectifier circuit; The output end of the rectifier circuit is connected to the input end of the 电路-shaped circuit formed by the blocking diode and the filter capacitor, and the output end of the Π-shaped circuit is the output end of the power module.

The sensor control module is a microprocessor or an analog circuit.

1. The sensor control module is a microprocessor, and the control signal output end of the microprocessor is respectively connected to drive the red LED and the infrared light LED through the driving circuit; meanwhile, the microprocessor acts as a sensor signal processing module, and the output end of the sensor is connected to the micro Processed signal input;

Or,

Second, the sensor control module is an analog circuit, and the analog circuit includes:

The other end of one end of the PIN diode is connected to the input end of the amplifying circuit, and the output end of the amplifying circuit is connected The acquisition signal output line of the audio interface is used as the sensor signal processing module.

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

The method is based on a vital sign collection device (hereinafter referred to as a collection device). The collecting device accesses the mobile device through the audio interface, supplies power through the audio interface and transmits data, and encodes the audio signal when transmitting the data, and the user enables the personal medical application software on the mobile device, and the personal medical application software communicates with the collecting device through the audio interface. Handshake, allowing the user to perform vital sign measurements after the device is discovered. When the user performs vital sign measurement, the application software controls the acquisition device through the audio port to collect signals and receive the collected signals. After sampling, filtering, numerical calculation, etc., the vital sign values are obtained, and the vital sign values can be displayed on the mobile terminal screen in real time. It can be stored in the persistent storage space of the mobile terminal to establish a personal medical database and perform data analysis according to various application requirements. At the same time, the mobile terminal's remote communication module can be used to transmit data to other places to meet remote real-time monitoring, remote diagnosis, remote health analysis and other requirements.

The blood oxygen vital sign measurement is taken as an example for further explanation.

FIG. 1 is a schematic structural diagram of a blood oxygen vital sign measurement system based on an audio interface according to an embodiment of the present invention. As shown in FIG. 1 , the system includes a blood oxygen vital sign collection device and a mobile device; a blood oxygen vital sign collection device (hereinafter referred to as a blood oxygen collection device) is connected to the mobile device through an audio port of the mobile device, and the mobile device is installed with blood. Oxygen measurement application software (hereinafter referred to as blood oxygen application software).

Figure 2 is a block diagram of the structure of the blood oxygen vital sign measurement system. As shown in Figure 2, the blood oxygen collection device includes a power module, an LED control module, a PIN signal processing module, an LED, and a PIN diode. The power module is connected to the left channel of the audio port of the mobile terminal, and is responsible for converting the sinusoidal electric signal output by the mobile terminal through the audio port into a stable voltage output, and providing power output for other modules. The LED control module is connected to the right channel of the mobile terminal, and is responsible for controlling the switching and current of the two LEDs by using the square wave signal output by the mobile terminal, thereby controlling the switching and intensity of the red and infrared light. The PIN signal processing module is responsible for converting and amplifying the electrical signal generated by the PIN diode to the microphone channel of the audio port of the mobile terminal.

The blood oxygen application software includes a power drive module, a sensor drive module, a sampling filter module, a calculation module, a data storage module, a data analysis module, and a remote communication module. The power drive module is responsible for generating a sine wave audio signal of a fixed frequency and outputting it to the power module of the acquisition device through the left channel of the audio port. The sensing driver module is responsible for generating a square wave signal and transmitting it to the LED control module of the acquisition device through the right channel of the audio port, driving the LED to generate red light and infrared light. The sampling filter module is responsible for the audio channel microphone channel The input analog signal is sampled, then filtered, the noise is removed, and its DC and AC components are separated. The calculation module is responsible for calculating the hemorrhage oxygen saturation value based on the DC component and calculating the pulse value based on the AC component. The data storage module is responsible for storing the calculated values to the persistent storage space of the mobile terminal. The data analysis module is responsible for analyzing the collected historical data and generating corresponding reports. The remote communication module is responsible for transmitting the collected data to other locations to meet remote real-time monitoring, remote diagnosis, remote health analysis and other requirements.

Figure 3 is a basic flow chart of the blood oxygen vital sign measurement system. As shown in Figure 3:

Step one is to supply power. The power driver module of the blood oxygen application software outputs a 22 kHz square wave to the blood oxygen collecting device through the left channel of the mobile device sound card, and the specific implementation is to play a 22 kHz square wave audio file. The power module in the blood oxygen collection device provides a stable power output by performing a series of processing on the square wave. The specific processing of the power module is as follows: First, the 22 kHz square wave is boosted by the step-up transformer, then the FET is rectified, and finally the stabilized power output is stabilized by the blocking diode and the filter capacitor to supply power to other processing circuits. Among them, the rectifier circuit has a dead zone voltage drop in the low voltage system, which is a key problem of the power module. For maximum power transmission, if a low-voltage diode such as the DFLS120L is used in the rectification process, it is found in the actual measurement that 80% of the power in the rectification has been lost, and only 20% is transmitted to the load. If FETs are used instead of diodes, synchronous finishing is often used to reduce losses. (The circuit schematic of the power module is shown in Figure 4.)

Step two is the driving and control of the LED. The sensor driver module of the blood oxygen application software generates a square wave, and the specific implementation is to play a square wave audio file. The square wave is transmitted to the LED control module of the blood oxygen collection device through the right channel of the audio port. The LED control module uses the rising edge of the square wave to control the switching between red and infrared light. The high voltage of the square wave controls the excitation current of the two LEDs of the sensor. The LED control module's electrical routing D flip-flop, the inverter constitutes a 1-bit binary counter, which realizes the switching of the two LEDs. The op amp and the three-stage tube form a voltage-controlled constant current circuit to realize the control of the excitation current of the two arc tubes. The circuit schematic is shown in Figure 5. (Better solution, that is, using digital signal, using mcu for control.)

Step 3 is the collection of blood oxygen vital signs. The LED module consists of two LED tubes. One emits red light (wavelength 660 nm). One emits infrared light (wavelength 940nm). The two LEDs are multiplexed 500 times per second under the control of the LED control module. The PIN diode is activated by two different LEDs through the body, producing an electrical signal containing blood oxygen information.

Step four is PIN blood oxygen signal processing. The PIN signal processing module removes the current signal through the PIN sensor, passes through the current amplifier formed by the operational amplifier, and amplifies the voltage signal to the MIC of the mobile terminal. Input. The amplifier is to amplify both AC and DC at the same time. The DC may be large, and the AC may be small. If the amplification factor is too high, the signal will enter saturation. At this time, the appropriate amplification factor should be used to control the excitation current to give appropriate gray. degree. Amplifiers We chose ADI's AD820 here. The circuit schematic of the PIN signal processing module is shown in Figure 6.

(The better solution is to use the digital signal method, use mcu to convert to digital signal, and process the digital signal to transmit and move.)

Step 5 is the sampling and filtering of the blood oxygen signal. The sampling filter module of the blood oxygen application software first samples the blood oxygen analog signal input from the microphone channel at 1000sps. The DC component of the sampled result is then extracted. Since the required cutoff frequency is very low, we use an IIR filter to track the DC component. The AC component is then obtained by subtracting the DC component from the input signal. Then we use a low-pass FIR filter with a frequency of 6Hz and 50Hz and above, with a 50dB attenuation to remove ambient noise above 50Hz in the AC component. At this time, the AC component signal is similar to the heartbeat pulse passing through the artery.

Step six is a numerical calculation. First, the RMS value is calculated for the DC component of the blood oxygen signal of red and infrared light, and the blood oxygen saturation is obtained by dividing the logarithm of the RMS value. The pulse is obtained by counting the number of samples in 3 beats.

Step 7 is data storage. We store the oxygen saturation and pulse values obtained by numerical calculations in the database that comes with the mobile terminal. Since the amount of data generated by blood oxygen collection is increasing rapidly, especially in the case of long-term continuous measurement, and the storage space of the mobile terminal is relatively limited, the key problem of data storage is the data compression algorithm. The algorithm we use is: if the measured values are the same over a period of time, they will be stored in a record of attributes such as start time, end time, number of measurements, measured values, etc., so that multiple measurements can be stored in one data record. result.

Step 8 is data analysis. The first is to perform statistical data on historical data, and secondly, to analyze according to specific requirements, such as sleep analysis. The analysis result is then stored in the storage space of the mobile terminal through the storage module.

Step 9 is the data display. Data is taken out from the data display module to the storage space of the mobile terminal, and the currently collected real-time data is displayed on the screen of the mobile terminal, and the result of the data analysis is displayed on the screen in a report and a graphic manner.

Step 10 is remote data transfer. The remote communication module uses the gprs module, 3G module or wifi module of the mobile terminal to connect to the Internet, and transmits the collected data to the remote server in real time or in batches, realizing real-time health monitoring, remote diagnosis, remote health analysis, remote data backup and the like. Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions and not limitation. While the present invention has been described in detail with reference to the embodiments of the present invention, it should be understood that Within the scope of the claims.

Claims

Claim

1. An oximeter based on audio port communication, characterized by comprising physical components of a power module, a sensor control module, a sensor, a sensor signal processing module, and a standard audio interface;

2. The oximeter based on audio port communication according to claim 1, wherein said power module comprises a step-up transformer, a FET rectifying circuit, a blocking diode and a filter capacitor; and a primary side of said step-up transformer is a power supply The input end of the module; the secondary side of the step-up transformer is connected to the input end of the FET rectifier circuit; the output end of the FET rectifier circuit is connected to the input end of the Π-shaped circuit formed by the blocking diode and the filter capacitor, and the output end of the Π-shaped circuit is The output of the power module.

3. The audio port communication based oximeter of claim 1, wherein the sensor control module and the sensor signal processing module are microprocessors or analog circuits.

4. The audio port communication based oximeter of claim 3, wherein said sensor comprises a PIN diode, a red LED, and an infrared LED; said PIN diode receiving red LED and infrared LED Light; one end of the PIN diode is connected to the power source, which is the output end of the sensor;

Or,

Second, the sensor control module is an analog circuit, which includes:

a) A 1-bit binary counter consisting of a D flip-flop and an inverter; the clock signal input of the D flip-flop is connected to the control signal input line of the audio interface, and the output of the D flip-flop is connected to the two inputs of the inverter The anode of the red LED and the infrared LED are respectively connected to the input end and the output end of the inverter; the D end of the D flip-flop is connected to the output end of the inverter;

5. An audio port communication based oximeter according to claim 3 or 4, wherein the microprocessor output further comprises a blood oxygen output.

6. The audio port communication based oximeter of claim 2 wherein said power module further comprises a farad capacitor in parallel with the Π-shaped circuit.