PC · Running Python

Contents

1. Hardware preparation
2. Hardware connection
3. Software environment setup
4. Running the example program
5. FAQ

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Hardware Preparation

Required Materials

Material	Description
JUXI_HeartRate_SPO2 sensor	Heart rate & SpO2 module
USB-to-TTL module	CH340 / CP2102 / FT232, etc.
Jumper wires	4 (female-to-female)
Windows computer	Win7/Win10/Win11

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Hardware Connection

Wiring

Sensor pin	USB-to-TTL pin	Description
VCC	3.3V or 5V	Power positive
GND	GND	Power negative
TX	RX	Sensor transmit → module receive
RX	TX	Sensor receive → module transmit

⚠️ Important notes:

1. Slide the module switch to UART!!!
2. TX and RX must be cross-connected!
3. The sensor supports 3.3V and 5V; do not connect the wrong voltage
4. Connect all wires first, then plug the USB into the computer

Wiring Diagram

传感器        USB转TTL模块
┌──────┐      ┌──────────┐
│ VCC  │──────│ 3.3V/5V  │
│ GND  │──────│ GND      │
│ TX   │──────│ RX       │  ← 交叉连接
│ RX   │──────│ TX       │  ← 交叉连接
└──────┘      └──────────┘

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Software Environment Setup

Installing the Driver

Install the corresponding driver according to your USB-to-TTL chip model:

• CH340: https://sparks.gogo.co.nz/ch340.html
• CP2102: https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers
• FT232: https://ftdichip.com/drivers/vcp-drivers/

After installation is complete, plug in the USB-to-TTL module.

Checking the COM Port

Method 1: Device Manager

1. Press Win + X and select "Device Manager"
2. Expand "Ports (COM & LPT)"
3. Find the COM port number corresponding to your USB-to-TTL adapter (e.g., COM3)

Method 2: Automatic Detection

When running the example program, all available serial ports are listed automatically.

Installing Python Dependencies

Open Command Prompt (CMD) or PowerShell and run:

pip install pyserial

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Running the Example Program

Download the archive JUXI_HeartRate_SPO2.zip and extract it

File Location

JUXI_HeartRate_SPO2/python/windows/
├── gain_heartbeat_SPO2.py  ← 主程序（直接运行这个）
├── JUXI_HeartRate_SPO2_Windows.py
├── JUXI_RTU_Windows.py
└── README_CN.md        ← 本文件
└── README.md

Run Steps

1. Confirm the hardware connection is correct

• VCC → 3.3V/5V
• GND → GND
• TX → RX (crossed)
• RX → TX (crossed)

1. Plug the USB into the computer
2. Run the program

cd D:\JUXI_HeartRate_SPO2\python\windows

python gain_heartbeat_SPO2.py

1. Follow the prompts

• The program lists all available serial ports
• Enter your COM port number (e.g., COM3)
• The program automatically detects the sensor and starts measuring

Expected Output

==================================================
JUXI Blood Oxygen Sensor - Windows Test
==================================================
Available serial ports:
  COM3

Please enter the COM port number (e.g., COM3):

Connecting to COM3 at 9600 baud...
Initializing sensor...
Sensor initialized successfully!

Starting data collection...
Sensor LED should be ON now!

Place your finger on the sensor...

SPO2 (血氧): 97 %
Heart Rate (心率): 82 BPM
Temperature (温度): 26.5 °C
SPO2 (血氧): 98 %
Heart Rate (心率): 78 BPM
Temperature (温度): 26.6 °C
...

Press Ctrl + C to stop the program.

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Program Features

Main API

# 创建传感器对象
sensor = BloodOxygenSensor("COM3", 9600)

# 初始化传感器
sensor.begin()

# 开始采集（LED亮起）
sensor.sensor_start_collect()

# 读取心率血氧
sensor.get_heartbeat_SPO2()
print(f"SPO2: {sensor.SPO2}%")
print(f"Heart Rate: {sensor.heartbeat} BPM")

# 读取温度
temp = sensor.get_temperature_c()

# 停止采集（LED熄灭）
sensor.sensor_end_collect()

# 关闭串口
sensor.close()

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FAQ

Q1: What should I do if the COM port cannot be found?

A:

1. Check whether the USB-to-TTL adapter is plugged in properly
2. Reinstall the driver
3. Try another USB port
4. Check Device Manager for any "Unknown device"

Q2: What should I do if sensor initialization fails?

A:

1. Check the wiring:

• Whether VCC and GND are connected correctly
• Whether TX and RX are cross-connected (the most common problem)

1. Confirm the baud rate is 9600
2. Check whether the USB-to-TTL module works properly
3. Unplug and replug the USB

Q3: What should I do if the data keeps showing -1?

A:

1. Confirm your finger is placed correctly on the sensor (completely covering the LED area)
2. Keep your finger steady and do not move
3. Wait a few seconds for the data to stabilize
4. Check whether the sensor LED is on

Q4: The LED is off but communication works?

A:

• It may be an LED hardware problem, but the sensor functions normally
• As long as the data is normal, the LED being off can be ignored

Q5: What should I do if the serial port is occupied?

A:

1. Close other serial software (serial assistant, Arduino IDE, etc.)
2. Check whether another Python program is running
3. Unplug and replug the USB

Q6: What should I do if the data is inaccurate?

A:

1. Make sure your finger completely covers the sensor's optical area
2. Stay quiet during measurement; do not talk or move
3. Wait more than 30 seconds for the data to stabilize
4. Take multiple measurements and average the results

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Technical Specifications

Parameter	Specification
Communication	UART (TTL level)
Baud rate	9600 bps (default)
Data format	8N1 (8 data bits, no parity, 1 stop bit)
Supply voltage	3.3V / 5V
SPO2 measurement range	35% - 100%
Heart rate measurement range	30 - 250 BPM
Modbus device address	0x20

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Modbus Registers

Register address	Function	Description
0x02	Device ID	Read: returns 0x0020
0x06-0x09	Heart rate & SpO2 data	Read: SPO2 + heart rate
0x0A	Temperature	Read: onboard temperature
0x10	Collection control	Write: 0x0001=start, 0x0002=stop