前回はWio Terminalの基本機能の一部を堪能させていただきました。

Wio Terminal でカメラ画像を表示2 ー LovyanGFX 編ー

今回は少し応用でWio Terminal を用いてパルスオキシメータを作ってみました。
トレンディーでしょ？ウフフ

心拍数センサ MAX30105

センサにはMAX30105を使用しました。
赤、緑、赤外線LEDと高感度光子検出器を搭載したモジュールで、
粉塵や血中酸素飽和度（SpO2）などを測ることができます。

Wio Terminalとの接続

MAX30105をWio Terminalの4ピンのGroveコネクタに接続します。

Wio Terminalの回路図を紐解くと2個のGroveコネクタの左側がハードウェアI2Cとつながっておりました。

パルスオキシメータ動作

酸素飽和度（SpO2）、脈拍数と心電図を表示しています。
心拍に合わせてブザーで音も出しています。

この投稿をInstagramで見る

Pulse Oximeter using Wio Terminal #WioTerminal

HomeMadeGarbage(@homemadegarbage)がシェアした投稿 – 2020年 5月月15日午後5時54分PDT

ブザー音の演出も功を奏し、いい感じの仕上がりとなりました♪

Arduino コード

MAX30105のライブラリは以下にございます。
　https://github.com/sparkfun/SparkFun_MAX3010x_Sensor_Library

以下のサンプルコードを参考にコーディングしました。

Wio TerminalのLCD表示は以下を参考にいたしました。
　https://wiki.seeedstudio.com/Wio-Terminal-LCD-Linecharts/

　
ブザー音出力は以下を参考にしました。
　https://wiki.seeedstudio.com/Wio-Terminal-Buzzer/

#include <Wire.h>
#include "MAX30105.h"

#include"seeed_line_chart.h" //include the library
#include "spo2_algorithm.h"

MAX30105 particleSensor;
TFT_eSPI tft;

long baseValue = 0;
long HB = 0, oldHB = 0;
int diffHB = 0;
int state = 0;
int th = -500;
 
#define max_size 50 //maximum size of data
doubles data; //Initilising a doubles type to store data
TFT_eSprite spr = TFT_eSprite(&tft);  // Sprite 


long lastBeat = 0; //Time at which the last beat occurred
const byte RATE_SIZE = 4; //Increase this for more averaging. 4 is good.
byte rates[RATE_SIZE]; //Array of heart rates
byte rateSpot = 0;

float beatsPerMinute;
int beatAvg;
long delta;


#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

void setup() {
  pinMode(WIO_BUZZER, OUTPUT);
  tft.begin();
  tft.setRotation(3);
  spr.createSprite(TFT_HEIGHT,TFT_WIDTH);

  Serial.begin(115200);
  Serial.println("Initializing...");

  // Initialize sensor
  if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
  {
    Serial.println("MAX30105 was not found. Please check wiring/power. ");
    while (1);
  }

  particleSensor.setup(); //Configure sensor with default settings
  particleSensor.setPulseAmplitudeRed(20); //Turn Red LED to low to indicate sensor is running
  particleSensor.setPulseAmplitudeGreen(0); //Turn off Green LED
}
 
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];
      display();
    }

    //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

      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.print(spo2, DEC);

      Serial.print(F(", SPO2Valid="));
      Serial.println(validSPO2, DEC);

      display();
    }

    //After gathering 25 new samples recalculate HR and SP02
    maxim_heart_rate_and_oxygen_saturation(irBuffer, bufferLength, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);
  }
}


void display() {
    spr.fillSprite(TFT_WHITE);
    if (data.size() == max_size) {
        data.pop();//this is used to remove the first read variable
    }
    HB = particleSensor.getIR();
    
    diffHB = HB - oldHB;
    data.push(diffHB); //read variables and store in data

    if(state == 0 && diffHB < th){
      delta = millis() - lastBeat;
      lastBeat = millis();
      beatsPerMinute = 60 / (delta / 1000.0);

      rates[rateSpot++] = (byte)beatsPerMinute; //Store this reading in the array
      rateSpot %= RATE_SIZE; //Wrap variable

      //Take average of readings
      beatAvg = 0;
      for (byte x = 0 ; x < RATE_SIZE ; x++)
        beatAvg += rates[x];
      beatAvg /= RATE_SIZE;
      Serial.println(beatAvg);
      
      state = 1;
      analogWrite(WIO_BUZZER, 128);
      Serial.println("Beat!!!!!!!");
    }else if(state == 1 && diffHB > th){
      state = 0;
      analogWrite(WIO_BUZZER, 0);
    }

    
  //Settings for SpO2
    String stSpO2 = " SpO2:";
    if(validSPO2){
      stSpO2 += spo2;
    }else{
      stSpO2 += "-";
    }

    char charSpO2[20];
    stSpO2.toCharArray(charSpO2, 20);
  
    auto header =  text(0, 0)
                .value(charSpO2)
                .align(left)
                .valign(vcenter)
                .width(tft.width())
                .thickness(3);
                
    header.height(header.font_height() * 2);
    header.draw(); //Header height is the twice the height of the font


  //Settings for HeartRate
    String stHB = " HeartRate:";
    stHB += beatAvg;

    char charHB[20];
    stHB.toCharArray(charHB, 20);

    auto header2 =  text(0, header.height())
                .value(charHB)
                .align(left)
                .valign(vcenter)
                .width(tft.width())
                .thickness(3);
                
    header2.height(header.font_height() * 2);
    header2.draw(); //Header height is the twice the height of the font
    
 
  //Settings for the line graph
    auto content = line_chart(0, header.height() + header2.height()); //(x,y) where the line graph begins
         content
                .height(tft.height() - (header.height() + header2.height()) * 1.0) //actual height of the line chart
                .width(tft.width() - content.x() * 2) //actual width of the line chart
                .based_on(0.0) //Starting point of y-axis, must be a float
                .show_circle(false) //drawing a cirle at each point, default is on.
                .value(data) //passing through the data to line graph
                .color(TFT_PURPLE) //Setting the color for the line
                .draw();
 
    spr.pushSprite(0, 0);

    oldHB = HB;
}

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

#include <Wire.h>

#include "MAX30105.h"

#include"seeed_line_chart.h" //include the library

#include "spo2_algorithm.h"

MAX30105 particleSensor;

TFT_eSPI tft;

long baseValue = 0;

long HB = 0, oldHB = 0;

int diffHB = 0;

int state = 0;

int th = -500;

#define max_size 50 //maximum size of data

doubles data; //Initilising a doubles type to store data

TFT_eSprite spr = TFT_eSprite(&tft); // Sprite

long lastBeat = 0; //Time at which the last beat occurred

const byte RATE_SIZE = 4; //Increase this for more averaging. 4 is good.

byte rates[RATE_SIZE]; //Array of heart rates

byte rateSpot = 0;

float beatsPerMinute;

int beatAvg;

long delta;

#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

void setup() {

pinMode(WIO_BUZZER, OUTPUT);

tft.begin();

tft.setRotation(3);

spr.createSprite(TFT_HEIGHT,TFT_WIDTH);

Serial.begin(115200);

Serial.println("Initializing...");

// Initialize sensor

if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed

{

Serial.println("MAX30105 was not found. Please check wiring/power. ");

while (1);

}

particleSensor.setup(); //Configure sensor with default settings

particleSensor.setPulseAmplitudeRed(20); //Turn Red LED to low to indicate sensor is running

particleSensor.setPulseAmplitudeGreen(0); //Turn off Green LED

}

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];

display();

}

//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

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.print(spo2, DEC);

Serial.print(F(", SPO2Valid="));

Serial.println(validSPO2, DEC);

display();

}

//After gathering 25 new samples recalculate HR and SP02

maxim_heart_rate_and_oxygen_saturation(irBuffer, bufferLength, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);

}

void display() {

spr.fillSprite(TFT_WHITE);

if (data.size() == max_size) {

data.pop();//this is used to remove the first read variable

}

HB = particleSensor.getIR();

diffHB = HB - oldHB;

data.push(diffHB); //read variables and store in data

if(state == 0 && diffHB < th){

delta = millis() - lastBeat;

lastBeat = millis();

beatsPerMinute = 60 / (delta / 1000.0);

rates[rateSpot++] = (byte)beatsPerMinute; //Store this reading in the array

rateSpot %= RATE_SIZE; //Wrap variable

//Take average of readings

beatAvg = 0;

for (byte x = 0 ; x < RATE_SIZE ; x++)

beatAvg += rates[x];

beatAvg /= RATE_SIZE;

Serial.println(beatAvg);

state = 1;

analogWrite(WIO_BUZZER, 128);

Serial.println("Beat!!!!!!!");

}else if(state == 1 && diffHB > th){

state = 0;

analogWrite(WIO_BUZZER, 0);

}

//Settings for SpO2

String stSpO2 = " SpO2:";

if(validSPO2){

stSpO2 += spo2;

}else{

stSpO2 += "-";

}

char charSpO2[20];

stSpO2.toCharArray(charSpO2, 20);

auto header = text(0, 0)

.value(charSpO2)

.align(left)

.valign(vcenter)

.width(tft.width())

.thickness(3);

header.height(header.font_height() * 2);

header.draw(); //Header height is the twice the height of the font

//Settings for HeartRate

String stHB = " HeartRate:";

stHB += beatAvg;

char charHB[20];

stHB.toCharArray(charHB, 20);

auto header2 = text(0, header.height())

.value(charHB)

.align(left)

.valign(vcenter)

.width(tft.width())

.thickness(3);

header2.height(header.font_height() * 2);

header2.draw(); //Header height is the twice the height of the font

//Settings for the line graph

auto content = line_chart(0, header.height() + header2.height()); //(x,y) where the line graph begins

content

.height(tft.height() - (header.height() + header2.height()) * 1.0) //actual height of the line chart

.width(tft.width() - content.x() * 2) //actual width of the line chart

.based_on(0.0) //Starting point of y-axis, must be a float

.show_circle(false) //drawing a cirle at each point, default is on.

.value(data) //passing through the data to line graph

.color(TFT_PURPLE) //Setting the color for the line

.draw();

spr.pushSprite(0, 0);

oldHB = HB;

}

参考

ArduinoでintまたはStringをchar配列に変換する

コメントはこちらからコメントをキャンセル

このサイトはスパムを低減するために Akismet を使っています。コメントデータの処理方法の詳細はこちらをご覧ください。

心拍数センサ MAX30105

Wio Terminalとの接続

パルスオキシメータ動作

Arduino コード

参考

関連記事

コメントはこちらから コメントをキャンセル

コメントはこちらからコメントをキャンセル