Yarana Iot Guru
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🔗 ESP32 With MySQL Database Management

Log sensor data from ESP32 to a MySQL database using PHP (XAMPP or remote server). Full step-by-step guide for reliable IoT data storage

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🔗 ESP32 With MySQL Database Management

Things used in this project

Software apps and online services

Arduino IDE
Arduino IDE

Story

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Code

ESP32 Code — Send Data to Server (Arduino IDE)

C/C++
/*
 ESP32 -> MySQL via PHP (HTTP GET)
 Author: YaranaIoT Guru
*/

#include <WiFi.h>
#include <HTTPClient.h>
#include "DHT.h"

// --- Edit these ---
const char* ssid = "YourWiFiName";
const char* password = "YourWiFiPassword";
const char* serverURL = "http://YOUR_SERVER_IP_OR_DOMAIN/esp32/insert.php"; // change

#define DHTPIN 4        // sensor pin
#define DHTTYPE DHT22   // or DHT11
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  dht.begin();
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nConnected. IP: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  if (isnan(temperature) || isnan(humidity)) {
    Serial.println("Failed to read from DHT sensor!");
    delay(5000);
    return;
  }

  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String url = String(serverURL) + "?temperature=" + String(temperature, 2) + "&humidity=" + String(humidity, 2);
    Serial.print("Request URL: ");
    Serial.println(url);

    http.begin(url);
    int httpCode = http.GET();

    if (httpCode > 0) {
      String payload = http.getString();
      Serial.print("Response: ");
      Serial.println(payload);
    } else {
      Serial.print("HTTP request failed, error: ");
      Serial.println(httpCode);
    }
    http.end();
  } else {
    Serial.println("WiFi disconnected");
  }

  delay(60000); // send every 60 seconds
}

PHP Endpoint — insert.php (secure basic version

C/C++
<?php
// Simple insert.php - ESP32 to MySQL (basic, add security in production)
$servername = "localhost";
$username = "root";
$password = ""; // XAMPP default
$dbname = "esp32_data";

// Get data (supports GET and POST)
$temp = isset($_REQUEST['temperature']) ? $_REQUEST['temperature'] : null;
$hum  = isset($_REQUEST['humidity']) ? $_REQUEST['humidity'] : null;

// Basic validation
if ($temp === null || $hum === null) {
    http_response_code(400);
    echo "Missing parameters";
    exit;
}

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    http_response_code(500);
    die("Connection failed: " . $conn->connect_error);
}

// Prepare statement to avoid SQL injection
$stmt = $conn->prepare("INSERT INTO sensor_data (temperature, humidity) VALUES (?, ?)");
$stmt->bind_param("dd", $temp, $hum);

if ($stmt->execute()) {
    echo "OK";
} else {
    http_response_code(500);
    echo "DB Error";
}

$stmt->close();
$conn->close();
?>

📊 Optional: Web Interface to View Data (index.php

C/C++
<?php
$mysqli = new mysqli("localhost","root","","esp32_data");
if ($mysqli->connect_error) { die("DB error"); }
$res = $mysqli->query("SELECT * FROM sensor_data ORDER BY id DESC LIMIT 50");
?>
<!doctype html>
<html>
<head><title>ESP32 Data</title></head>
<body>
<h1>Recent Sensor Data</h1>
<table border=1>
<tr><th>ID</th><th>Temperature</th><th>Humidity</th><th>Time</th></tr>
<?php while($row = $res->fetch_assoc()): ?>
<tr>
  <td><?= $row['id'] ?></td>
  <td><?= $row['temperature'] ?></td>
  <td><?= $row['humidity'] ?></td>
  <td><?= $row['created_at'] ?></td>
</tr>
<?php endwhile; ?>
</table>
</body>
</html>

Credits

Yarana Iot Guru
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Thanks to YaranaIoT Guru.

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