一、Arduino与旭日X3派通信

1.查看X3派上python是否安装serial包

2.X3派与Arduino之间通过USB进行通信

3.在终端上输入 ls /dev/tty* 出现ACM0说明两者可以正常通信

4.在Arduino上烧录代码

void setup() 
{
  Serial.begin(9600);
}
void loop()
{
  if ( Serial.available())
    {
      if('s' == Serial.read())
        Serial.println("HelloWorld!");
     }
}

5.在X3派上测试是否能够收到信息

在终端下通过python3进行测试

最后print可以出现HelloWorld！

import serial
ser=serial.Serial('/dev/ttyACM0',9600,timeout=1)
while 1:
    ser.write('s'.encode())
    msg=ser.readall()
    print(msg)

ser.write('s')会报编码的错误，使用方法encode()解决。

6.权限不够，退出后终端输入sudo su进入管理员模式可以解决

二、MAX30102人体心率血氧检测模块在上位机旭日X3派上的数据显示

1.MAX30102

MAX30102是一种用于可穿戴健康设备的高灵敏度脉搏血氧仪和心率传感器。

MAX30102内部集成了一整套完整信号采集电路，包括光信号发射及接收、AD转换、环境光干扰消除及数字滤波部分，只将数字接口留给用户。

2.Arduino代码

#include <Wire.h>
#include "MAX30105.h"
#include "spo2_algorithm.h"
MAX30105 particleSensor;
#define MAX_BRIGHTNESS 255
#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
//Arduino Uno doesn't have enough SRAM to store 100 samples of IR led data and red led data in 32-bit format
//To solve this problem, 16-bit MSB of the sampled data will be truncated. Samples become 16-bit data.
uint16_t irBuffer[100]; //infrared LED sensor data
uint16_t redBuffer[100];  //red LED sensor data
#else
uint32_t irBuffer[100]; //infrared LED sensor data
uint32_t redBuffer[100];  //red LED sensor data
#endif
int32_t bufferLength; //data length
int32_t spo2; //SPO2 value
int8_t validSPO2; //indicator to show if the SPO2 calculation is valid
int32_t heartRate; //heart rate value
int8_t validHeartRate; //indicator to show if the heart rate calculation is valid
byte pulseLED = 11; //Must be on PWM pin
byte readLED = 13; //Blinks with each data read
void setup()
{
  Serial.begin(115200); // initialize serial communication at 115200 bits per second:
  pinMode(pulseLED, OUTPUT);
  pinMode(readLED, OUTPUT);
  // Initialize sensor
  if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
  {
    Serial.println(F("MAX30105 was not found. Please check wiring/power."));
    while (1);
  }
  //Serial.println(F("Attach sensor to finger with rubber band. Press any key to start conversion"));
  //while (Serial.available() == 0) ; //wait until user presses a key
  //Serial.read();
  byte ledBrightness = 60; //Options: 0=Off to 255=50mA
  byte sampleAverage = 4; //Options: 1, 2, 4, 8, 16, 32
  byte ledMode = 2; //Options: 1 = Red only, 2 = Red + IR, 3 = Red + IR + Green
  byte sampleRate = 100; //Options: 50, 100, 200, 400, 800, 1000, 1600, 3200
  int pulseWidth = 411; //Options: 69, 118, 215, 411
  int adcRange = 4096; //Options: 2048, 4096, 8192, 16384
  particleSensor.setup(ledBrightness, sampleAverage, ledMode, sampleRate, pulseWidth, adcRange); //Configure sensor with these settings
}

void loop()
{
  bufferLength = 100; //buffer length of 100 stores 4 seconds of samples running at 25sps
  //read the first 100 samples, and determine the signal range
  for (byte i = 0 ; i < bufferLength ; i++)
  {
    while (particleSensor.available() == false) //do we have new data?
    particleSensor.check(); //Check the sensor for new data
    redBuffer[i] = particleSensor.getRed();
    irBuffer[i] = particleSensor.getIR();
    particleSensor.nextSample(); //We're finished with this sample so move to next sample
    Serial.print(F("red="));
    Serial.print(redBuffer[i], DEC);
    Serial.print(F(", ir="));
    Serial.println(irBuffer[i], DEC);
  }
  //calculate heart rate and SpO2 after first 100 samples (first 4 seconds of samples)
  maxim_heart_rate_and_oxygen_saturation(irBuffer, bufferLength, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);
  //Continuously taking samples from MAX30102.  Heart rate and SpO2 are calculated every 1 second
  while (1)
  {
    //dumping the first 25 sets of samples in the memory and shift the last 75 sets of samples to the top
    for (byte i = 25; i < 100; i++)
    {
      redBuffer[i - 25] = redBuffer[i];
      irBuffer[i - 25] = irBuffer[i];
    }
   //take 25 sets of samples before calculating the heart rate.
    for (byte i = 75; i < 100; i++)
    {
      while (particleSensor.available() == false) //do we have new data?
      particleSensor.check(); //Check the sensor for new data
      digitalWrite(readLED, !digitalRead(readLED)); //Blink onboard LED with every data read
      redBuffer[i] = particleSensor.getRed();
      irBuffer[i] = particleSensor.getIR();
      particleSensor.nextSample(); //We're finished with this sample so move to next sample
      //send samples and calculation result to terminal program through UART
      //Serial.print(F("red="));
      //Serial.print(redBuffer[i], DEC);
      //Serial.print(F(", ir="));
      //Serial.print(irBuffer[i], DEC);
      Serial.print(F(", HR="));
      Serial.print(heartRate, DEC);
      //Serial.print(F(", HRvalid="));
      //Serial.print(validHeartRate, DEC);
      Serial.print(F(", SPO2="));
      Serial.println(spo2, DEC);
      //Serial.print(F(", SPO2Valid="));
      //Serial.println(validSPO2, DEC);
    }
    //After gathering 25 new samples recalculate HR and SP02
    maxim_heart_rate_and_oxygen_saturation(irBuffer, bufferLength, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);
  }
}

3.接线

VCC----5V

GND---GND

SCL----A5

SDA---A4

将MAX30102周围用绝缘黑胶布包裹起来，避免手碰到电阻对结果产生影响

4.X3派代码

sudo nano max30102_test.py

import serial
ser=serial.Serial('/dev/ttyACM0',115200,timeout=1)
while 1:
    msg=ser.read(10)
    print(msg)

5.运行代码

python3 max30102_test.py

将手放上测量心率血氧，心率可以较快得出，血氧需要等待较久。

HR为心率，SPO2为血氧，ir和red为计算的中间值。

本文转自地平线开发者社区

原作者：jmulin

原链接：https://developer.horizon.ai/forumDetail/98129540173361549