LED on MAX300102 does not light up

Other Hardware Sensors
1

i'm having a similar problem as what was previously discussed here:

I tried doing what was written there, but still nothing works.

2

Have you tried the I2C scanner sketch?
Do you have the same exact set-up as @zarin12027, same parts and wiring?

3

yes but still could not light up

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4

Does not look like it, that is not an Uno and it looks like you have other things connected.

Please provide information on the components you are using and a diagram showing how they are connected.
Also post the code you are using, use code tags <CODE/>

5

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#include <WiFi.h>
#include <WebServer.h>
#include <Wire.h>
#include "MAX30100_PulseOximeter.h"
#include <OneWire.h>
#include <DallasTemperature.h>
#include <DHT.h>  // Adafruit library

// Pin Definitions
#define DHTPIN 4
#define DHTTYPE DHT11
#define DS18B20 5
#define BUZZER_PIN 2     // CHANGED: Moved from 13 to 2
#define REPORTING_PERIOD_MS 1000

// Health Thresholds
const float TEMP_HIGH = 38.0;
const float TEMP_LOW = 35.0;
const float BPM_HIGH = 120.0;
const float BPM_LOW = 50.0;
const float SPO2_LOW = 90.0;

float temperature, humidity, BPM, SpO2, bodytemperature;

const char* ssid = "Project123";  
const char* password = "Password123"; 

DHT dht_sensor(DHTPIN, DHTTYPE); 
PulseOximeter pox;
uint32_t tsLastReport = 0;
OneWire oneWire(DS18B20);
DallasTemperature sensors(&oneWire);

WebServer server(80);              

// Heartbeat sound (short chirp)
void onBeatDetected() {
  digitalWrite(BUZZER_PIN, HIGH);
  delay(20); 
  digitalWrite(BUZZER_PIN, LOW);
}
 
void setup() {
  Serial.begin(115200);
  pinMode(BUZZER_PIN, OUTPUT); 
  
  // --- STARTUP BEEP ---
  // Confirms the buzzer is working on Pin 2 immediately
  digitalWrite(BUZZER_PIN, HIGH);
  delay(200);
  digitalWrite(BUZZER_PIN, LOW);

  dht_sensor.begin(); 
  sensors.begin();

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  
  server.on("/", handle_OnConnect);
  server.onNotFound(handle_NotFound);
  server.begin();

  if (!pox.begin()) {
    Serial.println("Pox Error - Skipping...");
  } else {
    pox.setOnBeatDetectedCallback(onBeatDetected);
  }
  
  pox.setIRLedCurrent(MAX30100_LED_CURR_7_6MA);
}

void loop() {
  server.handleClient();
  pox.update();
  
  // Read Sensors
  sensors.requestTemperatures();
  temperature = dht_sensor.readTemperature(); 
  humidity = dht_sensor.readHumidity();       
  BPM = pox.getHeartRate();
  SpO2 = pox.getSpO2();
  bodytemperature = sensors.getTempCByIndex(0);

  // --- ALARM LOGIC ---
  bool isEmergency = false;

  // Check for abnormal vitals
  // Only trigger if sensor values are "active" (above 10) to prevent false alarms when disconnected
  if (SpO2 > 10 && SpO2 < SPO2_LOW) isEmergency = true;
  if (bodytemperature > 10 && (bodytemperature > TEMP_HIGH || bodytemperature < TEMP_LOW)) isEmergency = true;
  if (BPM > 10 && (BPM > BPM_HIGH || BPM < BPM_LOW)) isEmergency = true;

  if (isEmergency) {
    digitalWrite(BUZZER_PIN, HIGH); // Alarm stays ON
  } else {
    // Pin remains LOW (unless chirping in the onBeatDetected callback)
  }

  if (millis() - tsLastReport > REPORTING_PERIOD_MS) {
    tsLastReport = millis();
    Serial.print("BPM: "); Serial.print(BPM);
    Serial.print(" | SpO2: "); Serial.print(SpO2);
    Serial.print(" | BodyTemp: "); Serial.println(bodytemperature);
  }
}

void handle_OnConnect() {
  server.send(200, "text/html", SendHTML()); 
}

void handle_NotFound(){
  server.send(404, "text/plain", "Not found");
}

String SendHTML(){
  String ptr = "<!DOCTYPE html><html><head><meta name='viewport' content='width=device-width, initial-scale=1.0'>";
  ptr +="<style>body{font-family:sans-serif; text-align:center; background:#f0f2f5;}";
  ptr +=".card{background:white; padding:15px; margin:10px auto; border-radius:12px; width:85%; max-width:400px; box-shadow:0 4px 6px rgba(0,0,0,0.1);}";
  ptr +="h1{color:#1a73e8;} .val{font-size:32px; font-weight:bold; color:#d93025;}</style></head><body>";
  ptr +="<h1>Patient Monitor</h1>";
  ptr +="<div class='card'><div>Body Temp</div><div class='val'>" + String(bodytemperature, 1) + " &deg;C</div></div>";
  ptr +="<div class='card'><div>Heart Rate</div><div class='val'>" + String((int)BPM) + " BPM</div></div>";
  ptr +="<div class='card'><div>SpO2</div><div class='val'>" + String((int)SpO2) + " %</div></div>";
  ptr +="<div class='card' style='font-size:14px; color:#555;'>Room: " + String(temperature, 1) + "C | " + String(humidity, 0) + "%</div>";
  ptr +="</body></html>";
  return ptr;
}
6

Looks like you have a breadboard with the split power rails.
You need to connect them with small wire connections like this

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7

still max300102 LED did not light up. the code run successful but not reading for the heart beat rate and the oxygen level. Any solution for that problem?

8

zarin12027 used the MAX30105 library. Try the code zarin12027 used

9

i just run the code the max300102 LED light up now. Thank you