Pulsar - ESP32 code

esp32Heart.ino

// Author: Mason Manetta
#include <Wire.h>
#include "MAX30105.h"
#include "heartRate.h"
#include <WiFi.h>
#include <HTTPClient.h>

//Global Variables
MAX30105 particleSensor;

//Server EndPoint 
String serverPostUrl = "https://esp32-proxy.glitch.me/v1/bioMetricPost";

// WiFi config
const char *SSID = "esp32test";
const char *PWD = "$5P5402j";

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

float beatsPerMinute;
int beatAvg;
long irValue;

//Server running on port 80

//Functions for wifi

void connectToWiFi() {
  Serial.print("Connecting to ");
  Serial.println(SSID);

  WiFi.begin(SSID, PWD);

  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
    // we can even make the ESP32 to sleep
  }

  Serial.print("Connected. IP: ");
  Serial.println(WiFi.localIP());
}

void postDataToServer() {
 
  Serial.println("Posting JSON data to server...");
     
    HTTPClient http;   
     
    http.begin(serverPostUrl);  
    http.addHeader("Content-Type", "application/json");         

    String finger = "true";
    if (irValue < 50000)
      finger = "false";
    
    String response = "{";
    response += "\"finger\": " + finger +" ,"; 
    response += "\"oxygen\": 0 ,"; //hold 
    response += "\"irValue\": " + longToString(irValue) + ",";
    response += "\"cBPM\": " + String(beatsPerMinute) + ",";
    response += "\"aBPM\": " + String(beatAvg);
    response += "}";
     
    int httpResponseCode = http.POST(response);
 
    if(httpResponseCode>0){
       
      String response = http.getString();                       
       
      Serial.println(httpResponseCode);   
      Serial.println(response);
     
    }
    else {
     
      Serial.printf("Error occurred while sending HTTP POST");
       
    }
     
  }


String longToString(long longInteger){
  char buf[50];
  ltoa(longInteger, buf, 10);
  return(buf); 
}


void setup()
{
  //initialize serial connections
  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);
  }
  Serial.println("Place your index finger on the sensor with steady pressure.");

  particleSensor.setup(); //Configure sensor with default settings
  particleSensor.setPulseAmplitudeRed(0x0A); //Turn Red LED to low to indicate sensor is running
  particleSensor.setPulseAmplitudeGreen(0); //Turn off Green LED

  //Server Initialize
  connectToWiFi();

  //API Endpoints
}


void loop()
{
  int priorAverage = 0; 
  irValue = particleSensor.getIR();

  if (checkForBeat(irValue) == true)
  {
    //We sensed a beat!
    long delta = millis() - lastBeat;
    lastBeat = millis();

    beatsPerMinute = 60 / (delta / 1000.0);

    if (beatsPerMinute < 255 && beatsPerMinute > 20)
    {
      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;
      if(beatAvg != priorAverage){
        priorAverage = beatAvg;
        postDataToServer();
      }
    }
    //postDataToServer(); // post data to proxy
  }

  Serial.print("IR=");
  Serial.print(irValue);
  Serial.print(", BPM=");
  Serial.print(beatsPerMinute);
  Serial.print(", Avg BPM=");
  Serial.print(beatAvg);

  if (irValue < 50000)
    Serial.print(" No finger?");

  Serial.println();
}