Arduino + ESP8266-01 Wifi module + Pulse Rate Sensor + Node.js

[steshkaouuu]

Hello there! I'm Stephanie

Im working on a project with an Arduino Uno. I have connected the following to my Ardunio:

1. LED that lights up whenever the BPM < 150 is recorded.
2. ESP8266-01 WiFi module.
3. Pulse Rate sensor.

I want the values recorded by the Pulse rate sensor, to be displayed on my Node.js local web server through the ESP8266-01 wifi module and have the option to save the displayed data into a CSV. and example view can be the following:

Here are my codes:

Arduino:

#define USE_ARDUINO_INTERRUPTS true
#include <PulseSensorPlayground.h>
#include <WiFiEsp.h>
#include <SoftwareSerial.h>
#define DEBUG true

WiFiEspClient client;

const char ssid[] PROGMEM = "ssid";
const char password[] PROGMEM = "password";

// Replace with your server details
const char IP[] PROGMEM = "serverip";
const String serverURL = "/MyNodeApp/"; // Replace with your actual WebSocket endpoint

PulseSensorPlayground pulseSensor;
SoftwareSerial esp8266(10, 11);

const int LightBulbPin = 12;
const int LED13 = 13;
int Threshold = 550;
int myBPM;
char BPM[10];
int error;
unsigned long previousMillis = 0;
const unsigned long interval = 10000;

void connectWiFi() {
  esp8266.println(F("AT+CWMODE=1"));
  delay(2000);

  char cmd[50];
  snprintf_P(cmd, sizeof(cmd), PSTR("AT+CWJAP=\"%s\",\"%s\""), ssid, password);

  esp8266.println(cmd);
  delay(5000);

  if (!esp8266.find("OK")) {
    Serial.println("Failed to connect to WiFi");
    // Add any error handling or retry logic as needed
  }
}

void sendDataToServer() {
  String postData = "field1=" + String(BPM);

  Serial.println("Sending data to server: " + postData);

  client.print("POST ");
  client.print(serverURL);
  client.println(" HTTP/1.1");
  client.print("Host: ");
  client.println(IP);
  client.println("Content-Type: application/x-www-form-urlencoded");
  client.print("Content-Length: ");
  client.println(postData.length());
  client.println();
  client.print(postData);
}



void setup() {
  Serial.begin(9600);
  esp8266.begin(115200);
  pulseSensor.analogInput(A0);
  pulseSensor.blinkOnPulse(LED13);
  pulseSensor.setThreshold(Threshold);
  pinMode(LightBulbPin, OUTPUT);

  if (pulseSensor.begin()) {
Serial.println("Pulse Sensor Initialized");
  }

  if (esp8266.find("OK")) {
    connectWiFi();
  }
}

void loop() {
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    getReadings();
    sendDataToServer();
    previousMillis = currentMillis;
  }

  // Check if BPM is less than 150
  if (myBPM < 150) {
    digitalWrite(LightBulbPin, HIGH);  // Turn on the LED
  } else {
    digitalWrite(LightBulbPin, LOW);   // Turn off the LED
  }

  // Check and handle errors
  if (error == 1) {
    Serial.println("Error: " + error);
  }
}

void getReadings() {
  int newBPM = pulseSensor.getBeatsPerMinute();
  if (pulseSensor.sawStartOfBeat()) {
    myBPM = newBPM;

    // Convert integer BPM to string and update the BPM array
    snprintf(BPM, sizeof(BPM), "%d", myBPM);

    Serial.println(BPM);
  }
}

and this is my server.js code:

const express = require('express');

const bodyParser = require('body-parser');

const app = express();

const PORT = 3000;

// Use body-parser middleware

app.use(bodyParser.urlencoded({ extended: true }));

app.use(bodyParser.json());

// Handle a POST request

app.post('/example', (req, res) => {

const formData = req.body; // Access the parsed data

console.log('Received data:', formData);

res.send('Data received successfully');

});

app.listen(PORT, () => {

console.log(`Server running at serverip:${PORT}/`);

});

Please I would really appreciate any help on this!

[horace]

there are endless posts discussing problems with UNOs or Megas attempting to connect to internet services etc using an ESP-01, e.g. have a look at post connection-uno-with-esp01
the general recommendation is to move the project to a microcontroller with built in WiFi, e.g. an ESP32

Edit: for example see post esp32-cam-and-pulse-heart-rate-sensor