Pulse Oximeter with Alert Function

2021-11-16 | By M5Stack

License: General Public License Pulse Oximeter (PO / SpO2) Arduino

* Thanks for the source code and project information provided by @Gaku Hibi

Story

Due to the spread of COVID-19 overwhelming the capacity of the health care system, an increasing number of people stay home even if they are suspected as infected. Many people are concerned about their health, especially elderly people living alone.

This project can help people by sharing their health conditions, like heartbeat and blood oxygen level.

Measuring Heartbeat and SpO2

You can wire a Heart Rate Unit directly to M5Stack Basic via I2C.

The heart rate unit for M5Stack includes a MAX30100 chip, so you add "MAX30100lib" library with Adruino IDE Library Manager.

This library simply provides the functions to retrieve your heartbeat (getHeartRate()) and SpO2 (getSpO2()).

Connect a Sigfox Breakout board

Sigfox Breakout board [BRKWS01] only requires 3.3V input and Serial communication so the following pins are connected to the breakout board.

M5Stack BRKWS01

3V3 -> ( )

Ground -> (-)

RXD2(16) -> TX

TXD2(17) -> RX

Alert Email

Sigfox backend cloud has a callback function that can deliver messages to email addresses. This function allows us to alert family to a health condition.

In the sample code an alert message is sent when a button on M5Stack is pushed, though you can customize the message trigger, for instance, when reading is of concern.

Schematics

Code

M5Stack-Pulse-oximeter

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#include <M5Stack.h>
#include <Wire.h>
#include "MAX30100_PulseOximeter.h"
#include "xbm.h"  //my bitmap

#define REPORTING_PERIOD_MS     1000

PulseOximeter pox;
uint8_t Heart_rate = 0;
uint8_t Spo2 = 0;
uint32_t tsLastReport = 0;

// Callback (registered below) fired when a pulse is detected
void onBeatDetected()
{
  printHRandSPO2(true);
}

void setup()
{
  Serial.begin(115200); // to PC via USB
  Serial2.begin(9600, SERIAL_8N1, 16, 17);   // to Sigfox module

  M5.begin();
  M5.Power.begin();
  M5.Lcd.clear(BLACK);
  M5.Lcd.setTextSize(4);
  
  // Initialize sensor
  if (!pox.begin()) {
    M5.Lcd.println("FAILED");
    for(;;);
   } else {
    M5.Lcd.println("SUCCESS");
  }

  //LED Configuration
  pox.setIRLedCurrent(MAX30100_LED_CURR_7_6MA);
  //Register a callback for the beat detection
  pox.setOnBeatDetectedCallback(onBeatDetected);
}

void loop()
{
  M5.update();  //update button state
  pox.update(); //update pulse oximeter

  if (millis() - tsLastReport > REPORTING_PERIOD_MS) {
    Heart_rate = (int)pox.getHeartRate();
    Spo2 = pox.getSpO2();
    printHRandSPO2(false);
    tsLastReport = millis();
  }

  if (M5.BtnA.wasReleased()) {
    sendSigfoxMessage();
  }
}

void printHRandSPO2(bool beat)
{
  M5.Lcd.fillScreen(BLACK);
  M5.Lcd.setTextColor(WHITE);
  M5.Lcd.setTextSize(4);
  if (beat) {
    M5.Lcd.drawXBitmap(0, 5, hb2_bmp, 64, 32, TFT_RED);
  } else {
    M5.Lcd.drawXBitmap(0, 5, hb1_bmp, 64, 32, TFT_WHITE);
  }
  M5.Lcd.setCursor(0,70);
  M5.Lcd.print("HR:   "); M5.Lcd.println(Heart_rate);
  M5.Lcd.print("SPO2: "); M5.Lcd.println(Spo2);  
}

void sendSigfoxMessage() 
{
  String msg = "AT$SF="   String(Heart_rate, HEX)   String(Spo2, HEX);
  Serial2.println(msg);
  M5.Lcd.setCursor(0,160);
  M5.Lcd.println("MSG Sent!");
  delay(10000);
}

xbm.h

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#include <pgmspace.h>  // PROGMEM support header

#define imgWidth  64  // logo width
#define imgHeight 32  // logo height

static const uint8_t hb1_bmp[] = {
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x78, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xD8, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0xDC, 0x00, 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 
  0xDC, 0x00, 0x00, 0x00, 0x00, 0x38, 0x00, 0x00, 0xCC, 0x01, 0x00, 0x00, 
  0x00, 0x3C, 0x00, 0x00, 0xCC, 0x00, 0x00, 0x00, 0x00, 0x7C, 0x00, 0x00, 
  0x8C, 0x01, 0x00, 0x00, 0x00, 0x6E, 0x00, 0x00, 0x8C, 0x01, 0x00, 0x00, 
  0x00, 0xE6, 0x00, 0x00, 0x8E, 0x01, 0x00, 0x00, 0xF8, 0xC7, 0x0F, 0xFF, 
  0x87, 0xFF, 0xC0, 0x0F, 0xF0, 0x83, 0x1F, 0xFF, 0x07, 0xFF, 0xC1, 0x0F, 
  0x00, 0x00, 0x18, 0x03, 0x00, 0x80, 0xC1, 0x00, 0x00, 0x00, 0x9C, 0x01, 
  0x00, 0x80, 0x61, 0x00, 0x00, 0x00, 0x98, 0x01, 0x00, 0x80, 0x63, 0x00, 
  0x00, 0x00, 0xB0, 0x01, 0x00, 0x00, 0x73, 0x00, 0x00, 0x00, 0xF8, 0x01, 
  0x00, 0x00, 0x33, 0x00, 0x00, 0x00, 0xF0, 0x00, 0x00, 0x00, 0x3F, 0x00, 
  0x00, 0x00, 0xF0, 0x00, 0x00, 0x00, 0x1E, 0x00, 0x00, 0x00, 0xF0, 0x00, 
  0x00, 0x00, 0x1E, 0x00, 0x00, 0x00, 0x60, 0x00, 0x00, 0x00, 0x0E, 0x00, 
  0x00, 0x00, 0x60, 0x00, 0x00, 0x00, 0x0C, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, };

static const uint8_t hb2_bmp[] = {
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF8, 0x87, 0x0F, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0xFE, 0x8F, 0x1F, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 
  0x3F, 0x7F, 0x00, 0x00, 0x00, 0x00, 0x80, 0xFF, 0x3F, 0x7F, 0x00, 0x00, 
  0x00, 0x00, 0xC0, 0xFF, 0x7F, 0xFF, 0x00, 0x00, 0x00, 0x00, 0xC0, 0xFF, 
  0xE3, 0xFF, 0x01, 0x00, 0x00, 0x00, 0xE0, 0xFF, 0xC3, 0xFF, 0x01, 0x00, 
  0x00, 0x00, 0xE0, 0xFF, 0x99, 0xFF, 0x01, 0x00, 0x00, 0x00, 0xE0, 0xFF, 
  0x99, 0xFF, 0x03, 0x00, 0x00, 0x00, 0xE0, 0xFF, 0x3C, 0xFF, 0x03, 0x00, 
  0x00, 0x18, 0xE0, 0xFF, 0x3C, 0xFF, 0x03, 0x00, 0x00, 0x1C, 0xF0, 0xFF, 
  0x3C, 0xFF, 0x03, 0x00, 0x00, 0x3C, 0xE0, 0x7F, 0x6E, 0xFE, 0x03, 0x00, 
  0x00, 0x3E, 0xE0, 0x7F, 0x66, 0xFE, 0x01, 0x00, 0x00, 0x66, 0x60, 0x00, 
  0xE6, 0x00, 0x01, 0x00, 0x20, 0x67, 0x04, 0x11, 0xC7, 0x20, 0x01, 0x01, 
  0xF8, 0xE3, 0x07, 0xFF, 0xC3, 0x7F, 0xE0, 0x03, 0xF0, 0xC1, 0x8F, 0xFF, 
  0x83, 0x7F, 0xF0, 0x03, 0x00, 0x00, 0x8C, 0x01, 0x18, 0xE0, 0x30, 0x00, 
  0x00, 0x00, 0xDC, 0x11, 0xBC, 0xC2, 0x38, 0x00, 0x00, 0x00, 0xD8, 0xFC, 
  0xFF, 0xCF, 0x18, 0x00, 0x00, 0x00, 0xD8, 0xFC, 0xFF, 0xCF, 0x19, 0x00, 
  0x00, 0x00, 0xF8, 0xF8, 0xFF, 0x8F, 0x0D, 0x00, 0x00, 0x00, 0x78, 0xF0, 
  0xFF, 0x87, 0x0F, 0x00, 0x00, 0x00, 0x70, 0xE0, 0xFF, 0x83, 0x07, 0x00, 
  0x00, 0x00, 0x70, 0xC0, 0xFF, 0x01, 0x07, 0x00, 0x00, 0x00, 0x30, 0x00, 
  0x7F, 0x00, 0x03, 0x00, 0x00, 0x00, 0x20, 0x00, 0x3C, 0x00, 0x02, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, };