ESP32/ESP8266 Insert Data into MySQL Database using PHP and Arduino IDE

Posted byGnd_To_VccPosted inUncategorized

In this project you’ll build an ESP32 or ESP8266 client that makes an HTTP POST request to a PHP script to insert data (sensor readings) into a MySQL database.

You’ll also have a web page that displays the sensor readings, timestamp and other information from the database. You can visualize your data from anywhere in the world by accessing your own server.

As an example, we’ll be using a BME280 sensor connected to an ESP board. You can modify the code provided to send readings from a different sensor or use multiple boards.

In order to create build this project, you’ll use these technologies:

  • ESP32 or ESP8266 programmed with Arduino IDE
  • Hosting server and domain name
  • PHP script to insert data into MySQL and display it on a web page
  • MySQL database to store readings

1. Hosting Your PHP Application and MySQL Database

The goal of this project is to have your own domain name and hosting account that allows you to store sensor readings from the ESP32 or ESP8266. You can visualize the readings from anywhere in the world by accessing your own server domain. Here’s a high level overview:

I recommend using one of the following hosting services that can handle all the project requirements:

  • Bluehost (user-friendly with cPanel): free domain name when you sign up for the 3-year plan. I recommend choosing the unlimited websites option;
  • Digital Ocean: Linux server that you manage through a command line. I only recommended this option for advanced users.

Those two services are the ones that I use and personally recommend, but you can use any other hosting service. Any hosting service that offers PHP and MySQL will work with this tutorial. If you don’t have a hosting account, I recommend signing up for Bluehost.

Get Hosting and Domain Name with Bluehost »

When buying a hosting account, you’ll also have to purchase a domain name. This is what makes this project interesting: you’ll be able to go your domain name (http://example-domain.com) and see your ESP readings.

If you like our projects, you might consider signing up to one of the recommended hosting services, because you’ll be supporting our work.

Note: you can also run a LAMP (Linux, Apache, MySQL, PHP) server on a Raspberry Pi to access data in your local network. However, the purpose of this tutorial is to publish readings in your own domain name that you can access from anywhere in the world. This allows you to easily access your ESP readings without relying on a third-party IoT platform.

2. Preparing Your MySQL Database

After signing up for a hosting account and setting up a domain name, you can login to your cPanel or similar dashboard. After that, follow the next steps to create your database, username, password and SQL table.

Creating a database and user

1. Type “database” in the search bar and select “MySQL Database Wizard”.

2. Enter your desired Database name. In my case, the database name is esp_data. Then, press the “Next Step” button:

Note: later you’ll have to use the database name with the prefix that your host gives you (my database prefix in the screenshot above is blurred). I’ll refer to it as example_esp_data from now on.

3. Type your Database username and set a password. You must save all those details, because you’ll need them later to establish a database connection with your PHP code.

That’s it! Your new database and user were created successfully. Now, save all your details because you’ll need them later:

  • Database name: example_esp_data
  • Username: example_esp_board
  • Password: your password

Creating a SQL table

After creating your database and user, go back to cPanel dashboard and search for “phpMyAdmin”.

In the left sidebar, select your database name example_esp_data and open the “SQL” tab.

Important: make sure you’ve opened the example_esp_data database. Then, click the SQL tab. If you don’t follow these exact steps and run the SQL query, you might create a table in the wrong database.

Copy the SQL query in the following snippet:

CREATE TABLE SensorData (
    id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
    sensor VARCHAR(30) NOT NULL,
    location VARCHAR(30) NOT NULL,
    value1 VARCHAR(10),
    value2 VARCHAR(10),
    value3 VARCHAR(10),
    reading_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
)

After that, you should see your newly created table called SensorData in the example_esp_data database as shown in the figure below:

3. PHP Script HTTP POST – Insert Data in MySQL Database

In this section, we’re going to create a PHP script that is responsible for receiving incoming requests from the ESP32 or ESP8266 and inserting the data into a MySQL database.

If you’re using a hosting provider with cPanel, you can search for “File Manager”:

Then, select the public_html option and press the “+ File” button to create a new .php file.

Note: if you’re following this tutorial and you’re not familiar with PHP or MySQL, I recommend creating these exact files. Otherwise, you’ll need to modify the ESP sketch provided with different URL paths.

Create a new file in /public_html with this exact name and extension: post-esp-data.php

Edit the newly created file (post-esp-data.php) and copy the following snippet:

<?php

/*
  welcome to gnd_to_vcc!!
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files.
  
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
*/

$servername = "localhost";

// REPLACE with your Database name
$dbname = "REPLACE_WITH_YOUR_DATABASE_NAME";
// REPLACE with Database user
$username = "REPLACE_WITH_YOUR_USERNAME";
// REPLACE with Database user password
$password = "REPLACE_WITH_YOUR_PASSWORD";

// Keep this API Key value to be compatible with the ESP32 code provided in the project page. 
// If you change this value, the ESP32 sketch needs to match
$api_key_value = "tPmAT5Ab3j7F9";

$api_key= $sensor = $location = $value1 = $value2 = $value3 = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $api_key = test_input($_POST["api_key"]);
    if($api_key == $api_key_value) {
        $sensor = test_input($_POST["sensor"]);
        $location = test_input($_POST["location"]);
        $value1 = test_input($_POST["value1"]);
        $value2 = test_input($_POST["value2"]);
        $value3 = test_input($_POST["value3"]);
        
        // Create connection
        $conn = new mysqli($servername, $username, $password, $dbname);
        // Check connection
        if ($conn->connect_error) {
            die("Connection failed: " . $conn->connect_error);
        } 
        
        $sql = "INSERT INTO SensorData (sensor, location, value1, value2, value3)
        VALUES ('" . $sensor . "', '" . $location . "', '" . $value1 . "', '" . $value2 . "', '" . $value3 . "')";
        
        if ($conn->query($sql) === TRUE) {
            echo "New record created successfully";
        } 
        else {
            echo "Error: " . $sql . "<br>" . $conn->error;
        }
    
        $conn->close();
    }
    else {
        echo "Wrong API Key provided.";
    }

}
else {
    echo "No data posted with HTTP POST.";
}

function test_input($data) {
    $data = trim($data);
    $data = stripslashes($data);
    $data = htmlspecialchars($data);
    return $data;
}

Before saving the file, you need to modify the $dbname, $username and $password variables with your unique details:

// Your Database name
$dbname = "example_esp_data";
// Your Database user
$username = "example_esp_board";
// Your Database user password
$password = "YOUR_USER_PASSWORD";

After adding the database name, username and password, save the file and continue with this tutorial. If you try to access your domain name in the next URL path, you’ll see the following:

http://example-domain.com/post-esp-data.php

4. PHP Script – Display Database Content

Create another PHP file in the /public_html directory that will display all the database content in a web page. Name your new file: esp-data.php

PHP Create New file esp data

Edit the newly created file (esp-data.php) and copy the following code:

<!DOCTYPE html>
<html><body>
<?php
/*
gnf_to_vcc
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files.
  
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
*/

$servername = "localhost";

// REPLACE with your Database name
$dbname = "REPLACE_WITH_YOUR_DATABASE_NAME";
// REPLACE with Database user
$username = "REPLACE_WITH_YOUR_USERNAME";
// REPLACE with Database user password
$password = "REPLACE_WITH_YOUR_PASSWORD";

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

$sql = "SELECT id, sensor, location, value1, value2, value3, reading_time FROM SensorData ORDER BY id DESC";

echo '<table cellspacing="5" cellpadding="5">
      <tr> 
        <td>ID</td> 
        <td>Sensor</td> 
        <td>Location</td> 
        <td>Value 1</td> 
        <td>Value 2</td>
        <td>Value 3</td> 
        <td>Timestamp</td> 
      </tr>';
 
if ($result = $conn->query($sql)) {
    while ($row = $result->fetch_assoc()) {
        $row_id = $row["id"];
        $row_sensor = $row["sensor"];
        $row_location = $row["location"];
        $row_value1 = $row["value1"];
        $row_value2 = $row["value2"]; 
        $row_value3 = $row["value3"]; 
        $row_reading_time = $row["reading_time"];
        // Uncomment to set timezone to - 1 hour (you can change 1 to any number)
        //$row_reading_time = date("Y-m-d H:i:s", strtotime("$row_reading_time - 1 hours"));
      
        // Uncomment to set timezone to + 4 hours (you can change 4 to any number)
        //$row_reading_time = date("Y-m-d H:i:s", strtotime("$row_reading_time + 4 hours"));
      
        echo '<tr> 
                <td>' . $row_id . '</td> 
                <td>' . $row_sensor . '</td> 
                <td>' . $row_location . '</td> 
                <td>' . $row_value1 . '</td> 
                <td>' . $row_value2 . '</td>
                <td>' . $row_value3 . '</td> 
                <td>' . $row_reading_time . '</td> 
              </tr>';
    }
    $result->free();
}

$conn->close();
?> 
</table>
</body>
</html>

After adding the $dbname, $username and $password save the file and continue with this project.

// Your Database name
$dbname = "example_esp_data";
// Your Database user
$username = "example_esp_board";
// Your Database user password
$password = "YOUR_USER_PASSWORD";

If you try to access your domain name in the following URL path, you’ll see the following:

http://example-domain.com/esp-data.php

That’s it! If you see that empty table printed in your browser, it means that everything is ready. In the next section, you’ll learn how to insert data from your ESP32 or ESP8266 into the database.

5. Preparing Your ESP32 or ESP8266

This project is compatible with both the ESP32 and ESP8266 boards. You just need to assemble a simple circuit and upload the sketch provided to insert temperature, humidity, pressure and more into your database every 30 seconds.

Parts Required

For this example we’ll get sensor readings from the BME280 sensor. Here’s a list of parts you need to build the circuit for this project:

  • ESP32 board (read Best ESP32 dev boards)
  • Alternative – ESP8266 board (read Best ESP8266 dev boards)
  • BME280 sensor
  • Jumper wires
  • Breadboard

Schematics

The BME280 sensor module we’re using communicates via I2C communication protocol, so you need to connect it to the ESP32 or ESP8266 I2C pins.

BME280 wiring to ESP32

The ESP32 I2C pins are:

  • GPIO 22: SCL (SCK)
  • GPIO 21: SDA (SDI)

So, assemble your circuit as shown in the next schematic diagram (read complete Guide for ESP32 with BME280).

Recommended reading: ESP32 Pinout Reference Guide

BME280 wiring to ESP8266

The ESP8266 I2C pins are:

  • GPIO 5 (D1): SCL (SCK)
  • GPIO 4 (D2): SDA (SDI)

Assemble your circuit as in the next schematic diagram if you’re using an ESP8266 board (read complete Guide for ESP8266 with BME280).

Recommended reading: ESP8266 Pinout Reference Guide

ESP32/ESP8266 Code

We’ll program the ESP32/ESP8266 using Arduino IDE, so you must have the ESP32/ESP8266 add-on installed in your Arduino IDE. Follow one of the next tutorials depending on the board you’re using:

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After installing the necessary board add-ons, copy the following code to your Arduino IDE, but don’t upload it yet. You need to make some changes to make it work for you.

/*
 WELCOME TO GND_TO_VCC!!
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files.
  
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

*/

#ifdef ESP32
  #include <WiFi.h>
  #include <HTTPClient.h>
#else
  #include <ESP8266WiFi.h>
  #include <ESP8266HTTPClient.h>
  #include <WiFiClient.h>
#endif

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>

// Replace with your network credentials
const char* ssid     = "REPLACE_WITH_YOUR_SSID";
const char* password = "REPLACE_WITH_YOUR_PASSWORD";

// REPLACE with your Domain name and URL path or IP address with path
const char* serverName = "http://example.com/post-esp-data.php";

// Keep this API Key value to be compatible with the PHP code provided in the project page. 
// If you change the apiKeyValue value, the PHP file /post-esp-data.php also needs to have the same key 
String apiKeyValue = "tPmAT5Ab3j7F9";

String sensorName = "BME280";
String sensorLocation = "Office";

/*#include <SPI.h>
#define BME_SCK 18
#define BME_MISO 19
#define BME_MOSI 23
#define BME_CS 5*/

#define SEALEVELPRESSURE_HPA (1013.25)

Adafruit_BME280 bme;  // I2C
//Adafruit_BME280 bme(BME_CS);  // hardware SPI
//Adafruit_BME280 bme(BME_CS, BME_MOSI, BME_MISO, BME_SCK);  // software SPI

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

  // (you can also pass in a Wire library object like &Wire2)
  bool status = bme.begin(0x76);
  if (!status) {
    Serial.println("Could not find a valid BME280 sensor, check wiring or change I2C address!");
    while (1);
  }
}

void loop() {
  //Check WiFi connection status
  if(WiFi.status()== WL_CONNECTED){
    HTTPClient http;
    
    // Your Domain name with URL path or IP address with path
    http.begin(serverName);
    
    // Specify content-type header
    http.addHeader("Content-Type", "application/x-www-form-urlencoded");
    
    // Prepare your HTTP POST request data
    String httpRequestData = "api_key=" + apiKeyValue + "&sensor=" + sensorName
                          + "&location=" + sensorLocation + "&value1=" + String(bme.readTemperature())
                          + "&value2=" + String(bme.readHumidity()) + "&value3=" + String(bme.readPressure()/100.0F) + "";
    Serial.print("httpRequestData: ");
    Serial.println(httpRequestData);
    
    // You can comment the httpRequestData variable above
    // then, use the httpRequestData variable below (for testing purposes without the BME280 sensor)
    //String httpRequestData = "api_key=tPmAT5Ab3j7F9&sensor=BME280&location=Office&value1=24.75&value2=49.54&value3=1005.14";

    // Send HTTP POST request
    int httpResponseCode = http.POST(httpRequestData);
     
    // If you need an HTTP request with a content type: text/plain
    //http.addHeader("Content-Type", "text/plain");
    //int httpResponseCode = http.POST("Hello, World!");
    
    // If you need an HTTP request with a content type: application/json, use the following:
    //http.addHeader("Content-Type", "application/json");
    //int httpResponseCode = http.POST("{\"value1\":\"19\",\"value2\":\"67\",\"value3\":\"78\"}");
        
    if (httpResponseCode>0) {
      Serial.print("HTTP Response code: ");
      Serial.println(httpResponseCode);
    }
    else {
      Serial.print("Error code: ");
      Serial.println(httpResponseCode);
    }
    // Free resources
    http.end();
  }
  else {
    Serial.println("WiFi Disconnected");
  }
  //Send an HTTP POST request every 30 seconds
  delay(30000);  
}

Setting your network credentials

You need to modify the following lines with your network credentials: SSID and password. The code is well commented on where you should make the changes.

// Replace with your network credentials
const char* ssid     = "REPLACE_WITH_YOUR_SSID";
const char* password = "REPLACE_WITH_YOUR_PASSWORD";

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Setting your serverName

You also need to type your domain name, so the ESP publishes the readings to your own server.

const char* serverName = "http://example-domain.com/post-esp-data.php";

Now, you can upload the code to your board. It should work straight away both in the ESP32 or ESP8266 board. If you want to learn how the code works, read the next section.

How the code works

This project is already quite long, so we won’t cover in detail how the code works, but here’s a quick summary:

  • Import all the libraries to make it work (it will import either the ESP32 or ESP8266 libraries based on the selected board in your Arduino IDE)
  • Set variables that you might want to change (apiKeyValue, sensorName, sensorLocation)
  • The apiKeyValue is just a random string that you can modify. It’s used for security reasons, so only anyone that knows your API key can publish data to your database
  • Initialize the serial communication for debugging purposes
  • Establish a Wi-Fi connection with your router
  • Initialize the BME280 to get readings

Then, in the loop() is where you actually make the HTTP POST request every 30 seconds with the latest BME280 readings:

// Your Domain name with URL path or IP address with path
http.begin(serverName);

// Specify content-type header
http.addHeader("Content-Type", "application/x-www-form-urlencoded");

// Prepare your HTTP POST request data
String httpRequestData = "api_key=" + apiKeyValue + "&sensor=" + sensorName                      + "&location=" + sensorLocation + "&value1=" + String(bme.readTemperature())                      + "&value2=" + String(bme.readHumidity()) + "&value3=" + String(bme.readPressure()/100.0F) + "";

int httpResponseCode = http.POST(httpRequestData);

You can comment the httpRequestData variable above that concatenates all the BME280 readings and use the httpRequestData variable below for testing purposes:

String httpRequestData = "api_key=tPmAT5Ab3j7F9&sensor=BME280&location=Office&value1=24.75&value2=49.54&value3=1005.14";

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Demonstration

After completing all the steps, let your ESP board collect some readings and publish them to your server.

If everything is correct, this is what you should see in your Arduino IDE Serial Monitor:

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If you open your domain name in this URL path:

http://example-domain.com/esp-data.php

You should see the all the readings stored in your database. Refresh the web page to see the latest readings:

You can also go to phpMyAdmin to manage the data stored in your SensorData table. You can delete it, edit, etc…

Wrapping Up

In this tutorial you’ve learned how to publish sensor data into a database in your own server domain that you can access from anywhere in the world. This requires that you have your own server and domain name (you can use a Raspberry Pi for local access).

The example provided is as simple as possible so that you can understand how everything works. After understanding this example, you may change the appearance of the table, publish different sensor readings, publish from multiple ESP boards, and much more.

I hope you liked this project. If you have any questions, post a comment below and we’ll try to get back to you.

.

Thank you for reading.

Published by Gnd_To_Vcc

Here to spread my knowledge . Knowledge should always be spread not stored.

5 thoughts on “ESP32/ESP8266 Insert Data into MySQL Database using PHP and Arduino IDE”

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