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目录
MAX30102是一款集成了心率和血氧测量功能的传感器模块。它采用了专利的心率血氧测量技术,能够通过反射光谱测量来实时监测心率和血氧饱和度。
MAX30102传感器模块内置了红外光和红光LED,通过这两种光源照射皮肤,然后利用光电二极管接收反射光信号。这个过程中,红外光主要用于血氧测量,而红光则用于心率检测。
MAX30102传感器模块具有高灵敏度、低功耗和噪声抑制等特点,适用于可穿戴设备、医疗设备、运动健康监测等领域。它可以通过I2C接口与微控制器进行通信,并且提供了丰富的寄存器接口和算法库,方便开发者进行定制化的应用开发。
VIN(+):电源正极接口,外接电源 5V电源正极,接单片机的5v引脚
GND(-):电源负极接口,外接电源负极或地线GND,接单片机的GND
SCL :时钟线,接单片机的PB7引脚
SDA :数据线,接单片机的PB8引脚
INT :接单片机的PB9引脚
编译环境:keil5
测试单片机: STM32F103C8T6
功能:功能1:采集心率、血氧数据在OLED屏幕上显示出来
功能2:把采集心率、血氧数据发送到串口调试助手上
MAX30102.c文件编写心率血氧传感器驱动代码如下:
- #include "MAX30102.h"
- #include "MAX30102_IIC.h"
- #include "delay.h"
-
- u8 max30102_Bus_Write(u8 Register_Address, u8 Word_Data)
- {
-
- /* 采用串行EEPROM随即读取指令序列,连续读取若干字节 */
-
- /* 第1步:发起I2C总线启动信号 */
- IIC_Start();
-
- /* 第2步:发起控制字节,高7bit是地址,bit0是读写控制位,0表示写,1表示读 */
- IIC_Send_Byte(max30102_WR_address | I2C_WR); /* 此处是写指令 */
-
- /* 第3步:发送ACK */
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 第4步:发送字节地址 */
- IIC_Send_Byte(Register_Address);
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 第5步:开始写入数据 */
- IIC_Send_Byte(Word_Data);
-
- /* 第6步:发送ACK */
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 发送I2C总线停止信号 */
- IIC_Stop();
- return 1; /* 执行成功 */
-
- cmd_fail: /* 命令执行失败后,切记发送停止信号,避免影响I2C总线上其他设备 */
- /* 发送I2C总线停止信号 */
- IIC_Stop();
- return 0;
- }
-
-
-
- u8 max30102_Bus_Read(u8 Register_Address)
- {
- u8 data;
-
-
- /* 第1步:发起I2C总线启动信号 */
- IIC_Start();
-
- /* 第2步:发起控制字节,高7bit是地址,bit0是读写控制位,0表示写,1表示读 */
- IIC_Send_Byte(max30102_WR_address | I2C_WR); /* 此处是写指令 */
-
- /* 第3步:发送ACK */
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 第4步:发送字节地址, */
- IIC_Send_Byte((uint8_t)Register_Address);
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
-
- /* 第6步:重新启动I2C总线。下面开始读取数据 */
- IIC_Start();
-
- /* 第7步:发起控制字节,高7bit是地址,bit0是读写控制位,0表示写,1表示读 */
- IIC_Send_Byte(max30102_WR_address | I2C_RD); /* 此处是读指令 */
-
- /* 第8步:发送ACK */
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 第9步:读取数据 */
- {
- data = IIC_Read_Byte(0); /* 读1个字节 */
-
- IIC_NAck(); /* 最后1个字节读完后,CPU产生NACK信号(驱动SDA = 1) */
- }
- /* 发送I2C总线停止信号 */
- IIC_Stop();
- return data; /* 执行成功 返回data值 */
-
- cmd_fail: /* 命令执行失败后,切记发送停止信号,避免影响I2C总线上其他设备 */
- /* 发送I2C总线停止信号 */
- IIC_Stop();
- return 0;
- }
-
-
- void max30102_FIFO_ReadWords(u8 Register_Address,u16 Word_Data[][2],u8 count)
- {
- u8 i=0;
- u8 no = count;
- u8 data1, data2;
- /* 第1步:发起I2C总线启动信号 */
- IIC_Start();
-
- /* 第2步:发起控制字节,高7bit是地址,bit0是读写控制位,0表示写,1表示读 */
- IIC_Send_Byte(max30102_WR_address | I2C_WR); /* 此处是写指令 */
-
- /* 第3步:发送ACK */
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 第4步:发送字节地址, */
- IIC_Send_Byte((uint8_t)Register_Address);
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
-
- /* 第6步:重新启动I2C总线。下面开始读取数据 */
- IIC_Start();
-
- /* 第7步:发起控制字节,高7bit是地址,bit0是读写控制位,0表示写,1表示读 */
- IIC_Send_Byte(max30102_WR_address | I2C_RD); /* 此处是读指令 */
-
- /* 第8步:发送ACK */
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 第9步:读取数据 */
- while (no)
- {
- data1 = IIC_Read_Byte(0);
- IIC_Ack();
- data2 = IIC_Read_Byte(0);
- IIC_Ack();
- Word_Data[i][0] = (((u16)data1 << 8) | data2); //
-
-
- data1 = IIC_Read_Byte(0);
- IIC_Ack();
- data2 = IIC_Read_Byte(0);
- if(1==no)
- IIC_NAck(); /* 最后1个字节读完后,CPU产生NACK信号(驱动SDA = 1) */
- else
- IIC_Ack();
- Word_Data[i][1] = (((u16)data1 << 8) | data2);
-
- no--;
- i++;
- }
- /* 发送I2C总线停止信号 */
- IIC_Stop();
-
- cmd_fail: /* 命令执行失败后,切记发送停止信号,避免影响I2C总线上其他设备 */
- /* 发送I2C总线停止信号 */
- IIC_Stop();
- }
-
- void max30102_FIFO_ReadBytes(u8 Register_Address,u8* Data)
- {
- max30102_Bus_Read(REG_INTR_STATUS_1);
- max30102_Bus_Read(REG_INTR_STATUS_2);
-
- /* 第1步:发起I2C总线启动信号 */
- IIC_Start();
-
- /* 第2步:发起控制字节,高7bit是地址,bit0是读写控制位,0表示写,1表示读 */
- IIC_Send_Byte(max30102_WR_address | I2C_WR); /* 此处是写指令 */
-
- /* 第3步:发送ACK */
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 第4步:发送字节地址, */
- IIC_Send_Byte((uint8_t)Register_Address);
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
-
- /* 第6步:重新启动I2C总线。下面开始读取数据 */
- IIC_Start();
-
- /* 第7步:发起控制字节,高7bit是地址,bit0是读写控制位,0表示写,1表示读 */
- IIC_Send_Byte(max30102_WR_address | I2C_RD); /* 此处是读指令 */
-
- /* 第8步:发送ACK */
- if (IIC_Wait_Ack() != 0)
- {
- goto cmd_fail; /* EEPROM器件无应答 */
- }
-
- /* 第9步:读取数据 */
- Data[0] = IIC_Read_Byte(1);
- Data[1] = IIC_Read_Byte(1);
- Data[2] = IIC_Read_Byte(1);
- Data[3] = IIC_Read_Byte(1);
- Data[4] = IIC_Read_Byte(1);
- Data[5] = IIC_Read_Byte(0);
- /* 最后1个字节读完后,CPU产生NACK信号(驱动SDA = 1) */
- /* 发送I2C总线停止信号 */
- IIC_Stop();
-
- cmd_fail: /* 命令执行失败后,切记发送停止信号,避免影响I2C总线上其他设备 */
- /* 发送I2C总线停止信号 */
- IIC_Stop();
-
- // u8 i;
- // u8 fifo_wr_ptr;
- // u8 firo_rd_ptr;
- // u8 number_tp_read;
- // //Get the FIFO_WR_PTR
- // fifo_wr_ptr = max30102_Bus_Read(REG_FIFO_WR_PTR);
- // //Get the FIFO_RD_PTR
- // firo_rd_ptr = max30102_Bus_Read(REG_FIFO_RD_PTR);
- //
- // number_tp_read = fifo_wr_ptr - firo_rd_ptr;
- //
- // //for(i=0;i<number_tp_read;i++){
- // if(number_tp_read>0){
- // IIC_ReadBytes(max30102_WR_address,REG_FIFO_DATA,Data,6);
- // }
-
- //max30102_Bus_Write(REG_FIFO_RD_PTR,fifo_wr_ptr);
- }
-
- void max30102_init(void)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
- GPIO_Init(GPIOB, &GPIO_InitStructure);
-
- IIC_Init();
-
- max30102_reset();
-
- // max30102_Bus_Write(REG_MODE_CONFIG, 0x0b); //mode configuration : temp_en[3] MODE[2:0]=010 HR only enabled 011 SP02 enabled
- // max30102_Bus_Write(REG_INTR_STATUS_2, 0xF0); //open all of interrupt
- // max30102_Bus_Write(REG_INTR_STATUS_1, 0x00); //all interrupt clear
- // max30102_Bus_Write(REG_INTR_ENABLE_2, 0x02); //DIE_TEMP_RDY_EN
- // max30102_Bus_Write(REG_TEMP_CONFIG, 0x01); //SET TEMP_EN
-
- // max30102_Bus_Write(REG_SPO2_CONFIG, 0x47); //SPO2_SR[4:2]=001 100 per second LED_PW[1:0]=11 16BITS
-
- // max30102_Bus_Write(REG_LED1_PA, 0x47);
- // max30102_Bus_Write(REG_LED2_PA, 0x47);
-
-
-
- max30102_Bus_Write(REG_INTR_ENABLE_1,0xc0); // INTR setting
- max30102_Bus_Write(REG_INTR_ENABLE_2,0x00);
- max30102_Bus_Write(REG_FIFO_WR_PTR,0x00); //FIFO_WR_PTR[4:0]
- max30102_Bus_Write(REG_OVF_COUNTER,0x00); //OVF_COUNTER[4:0]
- max30102_Bus_Write(REG_FIFO_RD_PTR,0x00); //FIFO_RD_PTR[4:0]
- max30102_Bus_Write(REG_FIFO_CONFIG,0x0f); //sample avg = 1, fifo rollover=false, fifo almost full = 17
- max30102_Bus_Write(REG_MODE_CONFIG,0x03); //0x02 for Red only, 0x03 for SpO2 mode 0x07 multimode LED
- max30102_Bus_Write(REG_SPO2_CONFIG,0x27); // SPO2_ADC range = 4096nA, SPO2 sample rate (100 Hz), LED pulseWidth (400uS)
- max30102_Bus_Write(REG_LED1_PA,0x24); //Choose value for ~ 7mA for LED1
- max30102_Bus_Write(REG_LED2_PA,0x24); // Choose value for ~ 7mA for LED2
- max30102_Bus_Write(REG_PILOT_PA,0x7f); // Choose value for ~ 25mA for Pilot LED
-
-
-
- // // Interrupt Enable 1 Register. Set PPG_RDY_EN (data available in FIFO)
- // max30102_Bus_Write(0x2, 1<<6);
-
- // // FIFO configuration register
- // // SMP_AVE: 16 samples averaged per FIFO sample
- // // FIFO_ROLLOVER_EN=1
- // //max30102_Bus_Write(0x8, 1<<4);
- // max30102_Bus_Write(0x8, (0<<5) | 1<<4);
-
- // // Mode Configuration Register
- // // SPO2 mode
- // max30102_Bus_Write(0x9, 3);
-
- // // SPO2 Configuration Register
- // max30102_Bus_Write(0xa,
- // (3<<5) // SPO2_ADC_RGE 2 = full scale 8192 nA (LSB size 31.25pA); 3 = 16384nA
- // | (1<<2) // sample rate: 0 = 50sps; 1 = 100sps; 2 = 200sps
- // | (3<<0) // LED_PW 3 = 411μs, ADC resolution 18 bits
- // );
-
- // // LED1 (red) power (0 = 0mA; 255 = 50mA)
- // max30102_Bus_Write(0xc, 0xb0);
-
- // // LED (IR) power
- // max30102_Bus_Write(0xd, 0xa0);
-
- }
-
- void max30102_reset(void)
- {
- max30102_Bus_Write(REG_MODE_CONFIG,0x40);
- max30102_Bus_Write(REG_MODE_CONFIG,0x40);
- }
-
-
-
-
-
-
- void maxim_max30102_write_reg(uint8_t uch_addr, uint8_t uch_data)
- {
- // char ach_i2c_data[2];
- // ach_i2c_data[0]=uch_addr;
- // ach_i2c_data[1]=uch_data;
- //
- // IIC_WriteBytes(I2C_WRITE_ADDR, ach_i2c_data, 2);
- IIC_Write_One_Byte(I2C_WRITE_ADDR,uch_addr,uch_data);
- }
-
- void maxim_max30102_read_reg(uint8_t uch_addr, uint8_t *puch_data)
- {
- // char ch_i2c_data;
- // ch_i2c_data=uch_addr;
- // IIC_WriteBytes(I2C_WRITE_ADDR, &ch_i2c_data, 1);
- //
- // i2c.read(I2C_READ_ADDR, &ch_i2c_data, 1);
- //
- // *puch_data=(uint8_t) ch_i2c_data;
- IIC_Read_One_Byte(I2C_WRITE_ADDR,uch_addr,puch_data);
- }
-
- void maxim_max30102_read_fifo(uint32_t *pun_red_led, uint32_t *pun_ir_led)
- {
- uint32_t un_temp;
- unsigned char uch_temp;
- char ach_i2c_data[6];
- *pun_red_led=0;
- *pun_ir_led=0;
-
-
- //read and clear status register
- maxim_max30102_read_reg(REG_INTR_STATUS_1, &uch_temp);
- maxim_max30102_read_reg(REG_INTR_STATUS_2, &uch_temp);
-
- IIC_ReadBytes(I2C_WRITE_ADDR,REG_FIFO_DATA,(u8 *)ach_i2c_data,6);
-
- un_temp=(unsigned char) ach_i2c_data[0];
- un_temp<<=16;
- *pun_red_led+=un_temp;
- un_temp=(unsigned char) ach_i2c_data[1];
- un_temp<<=8;
- *pun_red_led+=un_temp;
- un_temp=(unsigned char) ach_i2c_data[2];
- *pun_red_led+=un_temp;
-
- un_temp=(unsigned char) ach_i2c_data[3];
- un_temp<<=16;
- *pun_ir_led+=un_temp;
- un_temp=(unsigned char) ach_i2c_data[4];
- un_temp<<=8;
- *pun_ir_led+=un_temp;
- un_temp=(unsigned char) ach_i2c_data[5];
- *pun_ir_led+=un_temp;
- *pun_red_led&=0x03FFFF; //Mask MSB [23:18]
- *pun_ir_led&=0x03FFFF; //Mask MSB [23:18]
- }
MAX30102_IIC.c文件编写心率血氧传感器IIC代码如下:
- #include "MAX30102_IIC.h"
- #include "delay.h"
-
- //初始化IIC
- void IIC_Init(void)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- //RCC->APB2ENR|=1<<4;//先使能外设IO PORTC时钟
- RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB, ENABLE );
-
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7|GPIO_Pin_8;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP ; //推挽输出
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOB, &GPIO_InitStructure);
-
- IIC_SCL=1;
- IIC_SDA=1;
-
- }
- //产生IIC起始信号
- void IIC_Start(void)
- {
- SDA_OUT(); //sda线输出
- IIC_SDA=1;
- IIC_SCL=1;
- Delay_us(4);
- IIC_SDA=0;//START:when CLK is high,DATA change form high to low
- Delay_us(4);
- IIC_SCL=0;//钳住I2C总线,准备发送或接收数据
- }
- //产生IIC停止信号
- void IIC_Stop(void)
- {
- SDA_OUT();//sda线输出
- IIC_SCL=0;
- IIC_SDA=0;//STOP:when CLK is high DATA change form low to high
- Delay_us(4);
- IIC_SCL=1;
- IIC_SDA=1;//发送I2C总线结束信号
- Delay_us(4);
- }
- //等待应答信号到来
- //返回值:1,接收应答失败
- // 0,接收应答成功
- u8 IIC_Wait_Ack(void)
- {
- u8 ucErrTime=0;
- SDA_IN(); //SDA设置为输入
- IIC_SDA=1;Delay_us(1);
- IIC_SCL=1;Delay_us(1);
- while(READ_SDA)
- {
- ucErrTime++;
- if(ucErrTime>250)
- {
- IIC_Stop();
- return 1;
- }
- }
- IIC_SCL=0;//时钟输出0
- return 0;
- }
- //产生ACK应答
- void IIC_Ack(void)
- {
- IIC_SCL=0;
- SDA_OUT();
- IIC_SDA=0;
- Delay_us(2);
- IIC_SCL=1;
- Delay_us(2);
- IIC_SCL=0;
- }
- //不产生ACK应答
- void IIC_NAck(void)
- {
- IIC_SCL=0;
- SDA_OUT();
- IIC_SDA=1;
- Delay_us(2);
- IIC_SCL=1;
- Delay_us(2);
- IIC_SCL=0;
- }
- //IIC发送一个字节
- //返回从机有无应答
- //1,有应答
- //0,无应答
- void IIC_Send_Byte(u8 txd)
- {
- u8 t;
- SDA_OUT();
- IIC_SCL=0;//拉低时钟开始数据传输
- for(t=0;t<8;t++)
- {
- IIC_SDA=(txd&0x80)>>7;
- txd<<=1;
- Delay_us(2); //对TEA5767这三个延时都是必须的
- IIC_SCL=1;
- Delay_us(2);
- IIC_SCL=0;
- Delay_us(2);
- }
- }
- //读1个字节,ack=1时,发送ACK,ack=0,发送nACK
- u8 IIC_Read_Byte(unsigned char ack)
- {
- unsigned char i,receive=0;
- SDA_IN();//SDA设置为输入
- for(i=0;i<8;i++ )
- {
- IIC_SCL=0;
- Delay_us(2);
- IIC_SCL=1;
- receive<<=1;
- if(READ_SDA)receive++;
- Delay_us(1);
- }
- if (!ack)
- IIC_NAck();//发送nACK
- else
- IIC_Ack(); //发送ACK
- return receive;
- }
-
-
- void IIC_WriteBytes(u8 WriteAddr,u8* data,u8 dataLength)
- {
- u8 i;
- IIC_Start();
-
- IIC_Send_Byte(WriteAddr); //发送写命令
- IIC_Wait_Ack();
-
- for(i=0;i<dataLength;i++)
- {
- IIC_Send_Byte(data[i]);
- IIC_Wait_Ack();
- }
- IIC_Stop();//产生一个停止条件
- Delay_ms(10);
- }
-
- void IIC_ReadBytes(u8 deviceAddr, u8 writeAddr,u8* data,u8 dataLength)
- {
- u8 i;
- IIC_Start();
-
- IIC_Send_Byte(deviceAddr); //发送写命令
- IIC_Wait_Ack();
- IIC_Send_Byte(writeAddr);
- IIC_Wait_Ack();
- IIC_Send_Byte(deviceAddr|0X01);//进入接收模式
- IIC_Wait_Ack();
-
- for(i=0;i<dataLength-1;i++)
- {
- data[i] = IIC_Read_Byte(1);
- }
- data[dataLength-1] = IIC_Read_Byte(0);
- IIC_Stop();//产生一个停止条件
- Delay_ms(10);
- }
-
- void IIC_Read_One_Byte(u8 daddr,u8 addr,u8* data)
- {
- IIC_Start();
-
- IIC_Send_Byte(daddr); //发送写命令
- IIC_Wait_Ack();
- IIC_Send_Byte(addr);//发送地址
- IIC_Wait_Ack();
- IIC_Start();
- IIC_Send_Byte(daddr|0X01);//进入接收模式
- IIC_Wait_Ack();
- *data = IIC_Read_Byte(0);
- IIC_Stop();//产生一个停止条件
- }
-
- void IIC_Write_One_Byte(u8 daddr,u8 addr,u8 data)
- {
- IIC_Start();
-
- IIC_Send_Byte(daddr); //发送写命令
- IIC_Wait_Ack();
- IIC_Send_Byte(addr);//发送地址
- IIC_Wait_Ack();
- IIC_Send_Byte(data); //发送字节
- IIC_Wait_Ack();
- IIC_Stop();//产生一个停止条件
- Delay_ms(10);
- }
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Algorithm.c文件编写心率血氧传感器算法代码如下:
- #include "algorithm.h"
-
- const uint16_t auw_hamm[31]={ 41, 276, 512, 276, 41 }; //Hamm= long16(512* hamming(5)');
- //uch_spo2_table is computed as -45.060*ratioAverage* ratioAverage + 30.354 *ratioAverage + 94.845 ;
- const uint8_t uch_spo2_table[184]={ 95, 95, 95, 96, 96, 96, 97, 97, 97, 97, 97, 98, 98, 98, 98, 98, 99, 99, 99, 99,
- 99, 99, 99, 99, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100, 100,
- 100, 100, 100, 100, 99, 99, 99, 99, 99, 99, 99, 99, 98, 98, 98, 98, 98, 98, 97, 97,
- 97, 97, 96, 96, 96, 96, 95, 95, 95, 94, 94, 94, 93, 93, 93, 92, 92, 92, 91, 91,
- 90, 90, 89, 89, 89, 88, 88, 87, 87, 86, 86, 85, 85, 84, 84, 83, 82, 82, 81, 81,
- 80, 80, 79, 78, 78, 77, 76, 76, 75, 74, 74, 73, 72, 72, 71, 70, 69, 69, 68, 67,
- 66, 66, 65, 64, 63, 62, 62, 61, 60, 59, 58, 57, 56, 56, 55, 54, 53, 52, 51, 50,
- 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 31, 30, 29,
- 28, 27, 26, 25, 23, 22, 21, 20, 19, 17, 16, 15, 14, 12, 11, 10, 9, 7, 6, 5,
- 3, 2, 1 } ;
- static int32_t an_dx[ BUFFER_SIZE-MA4_SIZE]; // delta
- static int32_t an_x[ BUFFER_SIZE]; //ir
- static int32_t an_y[ BUFFER_SIZE]; //red
-
- void maxim_heart_rate_and_oxygen_saturation(uint32_t *pun_ir_buffer, int32_t n_ir_buffer_length, uint32_t *pun_red_buffer, int32_t *pn_spo2, int8_t *pch_spo2_valid,
- int32_t *pn_heart_rate, int8_t *pch_hr_valid)
- /**
- * \brief Calculate the heart rate and SpO2 level
- * \par Details
- * By detecting peaks of PPG cycle and corresponding AC/DC of red/infra-red signal, the ratio for the SPO2 is computed.
- * Since this algorithm is aiming for Arm M0/M3. formaula for SPO2 did not achieve the accuracy due to register overflow.
- * Thus, accurate SPO2 is precalculated and save longo uch_spo2_table[] per each ratio.
- *
- * \param[in] *pun_ir_buffer - IR sensor data buffer
- * \param[in] n_ir_buffer_length - IR sensor data buffer length
- * \param[in] *pun_red_buffer - Red sensor data buffer
- * \param[out] *pn_spo2 - Calculated SpO2 value
- * \param[out] *pch_spo2_valid - 1 if the calculated SpO2 value is valid
- * \param[out] *pn_heart_rate - Calculated heart rate value
- * \param[out] *pch_hr_valid - 1 if the calculated heart rate value is valid
- *
- * \retval None
- */
- {
- uint32_t un_ir_mean ,un_only_once ;
- int32_t k ,n_i_ratio_count;
- int32_t i, s, m, n_exact_ir_valley_locs_count ,n_middle_idx;
- int32_t n_th1, n_npks,n_c_min;
- int32_t an_ir_valley_locs[15] ;
- int32_t an_exact_ir_valley_locs[15] ;
- int32_t an_dx_peak_locs[15] ;
- int32_t n_peak_interval_sum;
-
- int32_t n_y_ac, n_x_ac;
- int32_t n_spo2_calc;
- int32_t n_y_dc_max, n_x_dc_max;
- int32_t n_y_dc_max_idx, n_x_dc_max_idx;
- int32_t an_ratio[5],n_ratio_average;
- int32_t n_nume, n_denom ;
- // remove DC of ir signal
- un_ir_mean =0;
- for (k=0 ; k<n_ir_buffer_length ; k++ ) un_ir_mean += pun_ir_buffer[k] ;
- un_ir_mean =un_ir_mean/n_ir_buffer_length ;
- for (k=0 ; k<n_ir_buffer_length ; k++ ) an_x[k] = pun_ir_buffer[k] - un_ir_mean ;
-
- // 4 pt Moving Average
- for(k=0; k< BUFFER_SIZE-MA4_SIZE; k++){
- n_denom= ( an_x[k]+an_x[k+1]+ an_x[k+2]+ an_x[k+3]);
- an_x[k]= n_denom/(int32_t)4;
- }
-
- // get difference of smoothed IR signal
-
- for( k=0; k<BUFFER_SIZE-MA4_SIZE-1; k++)
- an_dx[k]= (an_x[k+1]- an_x[k]);
-
- // 2-pt Moving Average to an_dx
- for(k=0; k< BUFFER_SIZE-MA4_SIZE-2; k++){
- an_dx[k] = ( an_dx[k]+an_dx[k+1])/2 ;
- }
-
- // hamming window
- // flip wave form so that we can detect valley with peak detector
- for ( i=0 ; i<BUFFER_SIZE-HAMMING_SIZE-MA4_SIZE-2 ;i++){
- s= 0;
- for( k=i; k<i+ HAMMING_SIZE ;k++){
- s -= an_dx[k] *auw_hamm[k-i] ;
- }
- an_dx[i]= s/ (int32_t)1146; // divide by sum of auw_hamm
- }
-
-
- n_th1=0; // threshold calculation
- for ( k=0 ; k<BUFFER_SIZE-HAMMING_SIZE ;k++){
- n_th1 += ((an_dx[k]>0)? an_dx[k] : ((int32_t)0-an_dx[k])) ;
- }
- n_th1= n_th1/ ( BUFFER_SIZE-HAMMING_SIZE);
- // peak location is acutally index for sharpest location of raw signal since we flipped the signal
- maxim_find_peaks( an_dx_peak_locs, &n_npks, an_dx, BUFFER_SIZE-HAMMING_SIZE, n_th1, 8, 5 );//peak_height, peak_distance, max_num_peaks
-
- n_peak_interval_sum =0;
- if (n_npks>=2){
- for (k=1; k<n_npks; k++)
- n_peak_interval_sum += (an_dx_peak_locs[k]-an_dx_peak_locs[k -1]);
- n_peak_interval_sum=n_peak_interval_sum/(n_npks-1);
- *pn_heart_rate=(int32_t)(6000/n_peak_interval_sum);// beats per minutes
- *pch_hr_valid = 1;
- }
- else {
- *pn_heart_rate = -999;
- *pch_hr_valid = 0;
- }
-
- for ( k=0 ; k<n_npks ;k++)
- an_ir_valley_locs[k]=an_dx_peak_locs[k]+HAMMING_SIZE/2;
-
-
- // raw value : RED(=y) and IR(=X)
- // we need to assess DC and AC value of ir and red PPG.
- for (k=0 ; k<n_ir_buffer_length ; k++ ) {
- an_x[k] = pun_ir_buffer[k] ;
- an_y[k] = pun_red_buffer[k] ;
- }
-
- // find precise min near an_ir_valley_locs
- n_exact_ir_valley_locs_count =0;
- for(k=0 ; k<n_npks ;k++){
- un_only_once =1;
- m=an_ir_valley_locs[k];
- n_c_min= 16777216;//2^24;
- if (m+5 < BUFFER_SIZE-HAMMING_SIZE && m-5 >0){
- for(i= m-5;i<m+5; i++)
- if (an_x[i]<n_c_min){
- if (un_only_once >0){
- un_only_once =0;
- }
- n_c_min= an_x[i] ;
- an_exact_ir_valley_locs[k]=i;
- }
- if (un_only_once ==0)
- n_exact_ir_valley_locs_count ++ ;
- }
- }
- if (n_exact_ir_valley_locs_count <2 ){
- *pn_spo2 = -999 ; // do not use SPO2 since signal ratio is out of range
- *pch_spo2_valid = 0;
- return;
- }
- // 4 pt MA
- for(k=0; k< BUFFER_SIZE-MA4_SIZE; k++){
- an_x[k]=( an_x[k]+an_x[k+1]+ an_x[k+2]+ an_x[k+3])/(int32_t)4;
- an_y[k]=( an_y[k]+an_y[k+1]+ an_y[k+2]+ an_y[k+3])/(int32_t)4;
- }
-
- //using an_exact_ir_valley_locs , find ir-red DC andir-red AC for SPO2 calibration ratio
- //finding AC/DC maximum of raw ir * red between two valley locations
- n_ratio_average =0;
- n_i_ratio_count =0;
-
- for(k=0; k< 5; k++) an_ratio[k]=0;
- for (k=0; k< n_exact_ir_valley_locs_count; k++){
- if (an_exact_ir_valley_locs[k] > BUFFER_SIZE ){
- *pn_spo2 = -999 ; // do not use SPO2 since valley loc is out of range
- *pch_spo2_valid = 0;
- return;
- }
- }
- // find max between two valley locations
- // and use ratio betwen AC compoent of Ir & Red and DC compoent of Ir & Red for SPO2
-
- for (k=0; k< n_exact_ir_valley_locs_count-1; k++){
- n_y_dc_max= -16777216 ;
- n_x_dc_max= - 16777216;
- if (an_exact_ir_valley_locs[k+1]-an_exact_ir_valley_locs[k] >10){
- for (i=an_exact_ir_valley_locs[k]; i< an_exact_ir_valley_locs[k+1]; i++){
- if (an_x[i]> n_x_dc_max) {n_x_dc_max =an_x[i];n_x_dc_max_idx =i; }
- if (an_y[i]> n_y_dc_max) {n_y_dc_max =an_y[i];n_y_dc_max_idx=i;}
- }
- n_y_ac= (an_y[an_exact_ir_valley_locs[k+1]] - an_y[an_exact_ir_valley_locs[k] ] )*(n_y_dc_max_idx -an_exact_ir_valley_locs[k]); //red
- n_y_ac= an_y[an_exact_ir_valley_locs[k]] + n_y_ac/ (an_exact_ir_valley_locs[k+1] - an_exact_ir_valley_locs[k]) ;
-
-
- n_y_ac= an_y[n_y_dc_max_idx] - n_y_ac; // subracting linear DC compoenents from raw
- n_x_ac= (an_x[an_exact_ir_valley_locs[k+1]] - an_x[an_exact_ir_valley_locs[k] ] )*(n_x_dc_max_idx -an_exact_ir_valley_locs[k]); // ir
- n_x_ac= an_x[an_exact_ir_valley_locs[k]] + n_x_ac/ (an_exact_ir_valley_locs[k+1] - an_exact_ir_valley_locs[k]);
- n_x_ac= an_x[n_y_dc_max_idx] - n_x_ac; // subracting linear DC compoenents from raw
- n_nume=( n_y_ac *n_x_dc_max)>>7 ; //prepare X100 to preserve floating value
- n_denom= ( n_x_ac *n_y_dc_max)>>7;
- if (n_denom>0 && n_i_ratio_count <5 && n_nume != 0)
- {
- an_ratio[n_i_ratio_count]= (n_nume*20)/n_denom ; //formular is ( n_y_ac *n_x_dc_max) / ( n_x_ac *n_y_dc_max) ; ///*************************n_nume原来是*100************************//
- n_i_ratio_count++;
- }
- }
- }
-
- maxim_sort_ascend(an_ratio, n_i_ratio_count);
- n_middle_idx= n_i_ratio_count/2;
-
- if (n_middle_idx >1)
- n_ratio_average =( an_ratio[n_middle_idx-1] +an_ratio[n_middle_idx])/2; // use median
- else
- n_ratio_average = an_ratio[n_middle_idx ];
-
- if( n_ratio_average>2 && n_ratio_average <184){
- n_spo2_calc= uch_spo2_table[n_ratio_average] ;
- *pn_spo2 = n_spo2_calc ;
- *pch_spo2_valid = 1;// float_SPO2 = -45.060*n_ratio_average* n_ratio_average/10000 + 30.354 *n_ratio_average/100 + 94.845 ; // for comparison with table
- }
- else{
- *pn_spo2 = -999 ; // do not use SPO2 since signal ratio is out of range
- *pch_spo2_valid = 0;
- }
- }
-
-
- void maxim_find_peaks(int32_t *pn_locs, int32_t *pn_npks, int32_t *pn_x, int32_t n_size, int32_t n_min_height, int32_t n_min_distance, int32_t n_max_num)
- /**
- * \brief Find peaks
- * \par Details
- * Find at most MAX_NUM peaks above MIN_HEIGHT separated by at least MIN_DISTANCE
- *
- * \retval None
- */
- {
- maxim_peaks_above_min_height( pn_locs, pn_npks, pn_x, n_size, n_min_height );
- maxim_remove_close_peaks( pn_locs, pn_npks, pn_x, n_min_distance );
- *pn_npks = min( *pn_npks, n_max_num );
- }
-
- void maxim_peaks_above_min_height(int32_t *pn_locs, int32_t *pn_npks, int32_t *pn_x, int32_t n_size, int32_t n_min_height)
- /**
- * \brief Find peaks above n_min_height
- * \par Details
- * Find all peaks above MIN_HEIGHT
- *
- * \retval None
- */
- {
- int32_t i = 1, n_width;
- *pn_npks = 0;
-
- while (i < n_size-1){
- if (pn_x[i] > n_min_height && pn_x[i] > pn_x[i-1]){ // find left edge of potential peaks
- n_width = 1;
- while (i+n_width < n_size && pn_x[i] == pn_x[i+n_width]) // find flat peaks
- n_width++;
- if (pn_x[i] > pn_x[i+n_width] && (*pn_npks) < 15 ){ // find right edge of peaks
- pn_locs[(*pn_npks)++] = i;
- // for flat peaks, peak location is left edge
- i += n_width+1;
- }
- else
- i += n_width;
- }
- else
- i++;
- }
- }
-
-
- void maxim_remove_close_peaks(int32_t *pn_locs, int32_t *pn_npks, int32_t *pn_x, int32_t n_min_distance)
- /**
- * \brief Remove peaks
- * \par Details
- * Remove peaks separated by less than MIN_DISTANCE
- *
- * \retval None
- */
- {
-
- int32_t i, j, n_old_npks, n_dist;
-
- /* Order peaks from large to small */
- maxim_sort_indices_descend( pn_x, pn_locs, *pn_npks );
-
- for ( i = -1; i < *pn_npks; i++ ){
- n_old_npks = *pn_npks;
- *pn_npks = i+1;
- for ( j = i+1; j < n_old_npks; j++ ){
- n_dist = pn_locs[j] - ( i == -1 ? -1 : pn_locs[i] ); // lag-zero peak of autocorr is at index -1
- if ( n_dist > n_min_distance || n_dist < -n_min_distance )
- pn_locs[(*pn_npks)++] = pn_locs[j];
- }
- }
-
- // Resort indices longo ascending order
- maxim_sort_ascend( pn_locs, *pn_npks );
- }
-
- void maxim_sort_ascend(int32_t *pn_x,int32_t n_size)
- /**
- * \brief Sort array
- * \par Details
- * Sort array in ascending order (insertion sort algorithm)
- *
- * \retval None
- */
- {
- int32_t i, j, n_temp;
- for (i = 1; i < n_size; i++) {
- n_temp = pn_x[i];
- for (j = i; j > 0 && n_temp < pn_x[j-1]; j--)
- pn_x[j] = pn_x[j-1];
- pn_x[j] = n_temp;
- }
- }
-
- void maxim_sort_indices_descend(int32_t *pn_x, int32_t *pn_indx, int32_t n_size)
- /**
- * \brief Sort indices
- * \par Details
- * Sort indices according to descending order (insertion sort algorithm)
- *
- * \retval None
- */
- {
- int32_t i, j, n_temp;
- for (i = 1; i < n_size; i++) {
- n_temp = pn_indx[i];
- for (j = i; j > 0 && pn_x[n_temp] > pn_x[pn_indx[j-1]]; j--)
- pn_indx[j] = pn_indx[j-1];
- pn_indx[j] = n_temp;
- }
- }
-
- printf("心率= %d BPM 血氧= %d ",dis_hr,dis_spo2);
- Serial_SendString("%\r\n");
串口调试助手-keil5调试工具_dht11温度传感器串口资源-CSDN文库
《STM32单片机+MAX30102心率血氧传感器+OLED屏幕+心率血氧数据发送到串口调试助手》源代码资源-CSDN文库
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