Embedded System Project 9: Insert ESP32 Data Into MySQL
Hi, I’m Michelle and today I’ll be continuing my blog series of the embedded systems project! ✨🤩 (You can read the previous blog here 🤗)
The ninth project I’ll be doing is actually a bonus project, so I won’t be explaining too much theory in this project, but it will be more of a documentation of my experiment. In this project, we will be building an ESP32 client that makes an HTTP POST request to a PHP script to insert data (sensor readings) into a MySQL database.
By doing this project, we’ll also have a web page that displays the sensor readings, timestamps, and other information from the database. We can visualize the data from anywhere in the world by accessing our own server. 😲
Without further ado, let’s begin the experiment in this project!
Project: Introduction
The components we’ll be using are listed below.
- ESP32 Development Board
- BME280 Sensor
- Micro-USB Cable
- Breadboard
- Male-to-Male jumper wires
- Laptop/PC with Arduino IDE installed and set
We will also be needing these technologies listed below.
- Hosting server and domain name
- PHP script to insert data into MySQL and display it on a web page
- MySQL database to store readings
This is the main concept for this experiment.
Project: Website Managing
I’ll be using 000webhost.com to host!
Here are the steps.
1. Go to 000webhost.com
2. Sign up for a new account (I’m using the free one)
3. Create New Site > Choose domain name
4. Click on Manage Website > Tools > Database Manager > Create new database > Enter Database name > Enter Database username > Create
5. Click on Manage > PhpMyAdmin
6. Click on your DBName > Query > Copy and paste the query attached below > Submit query
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
)
10. Go to Structure section and you should see something like this
11. Go back to Manage Website > Tools > File Manager > Upload Files
12. Open public_html folder > New File > Name the new .php file > Create
13. Right click on the file you just created > Edit > Copy and paste the code attached below > Save
<?php
/*
Rui Santos
Complete project details at https://RandomNerdTutorials.com/esp32-esp8266-mysql-database-php/
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;
}Note : Don’t forget to change the dbname, username, and password.
14. Try visiting the websitename/phpfile.php and you should get something like this
Note: mine was https://michellesbonusprojects.000webhostapp.com/esp32data.php
This means our page has been successfully created!
15. Reopen public_html folder > New File > Name the new .php file > Create
16. Right click on the file you just created > Edit > Copy and paste the code attached below > Save
<!DOCTYPE html>
<html><body>
<?php
/*
Rui Santos
Complete project details at https://RandomNerdTutorials.com/esp32-esp8266-mysql-database-php/
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>Again, don’t forget to change the dbname, username, and password.
17. Try visiting the websitename/phpfile.php and you should get something like this
Note: mine was https://michellesbonusprojects.000webhostapp.com/esp32dataa.php
Project: Schematics
1. Wire your ESP32 and BME280 sensor as following.
2. Copy and paste the code below, compile and upload on Arduino IDE
/*
Rui Santos
Complete project details at https://RandomNerdTutorials.com/esp32-esp8266-mysql-database-php/
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.
*/
#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <HTTPClient.h>
#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 = "https://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){
WiFiClientSecure *client = new WiFiClientSecure;
client->setInsecure(); //don't use SSL certificate
HTTPClient https;
// Your Domain name with URL path or IP address with path
https.begin(*client, serverName);
// Specify content-type header
https.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 = https.POST(httpRequestData);
// If you need an HTTP request with a content type: text/plain
//https.addHeader("Content-Type", "text/plain");
//int httpResponseCode = https.POST("Hello, World!");
// If you need an HTTP request with a content type: application/json, use the following:
//https.addHeader("Content-Type", "application/json");
//int httpResponseCode = https.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
https.end();
}
else {
Serial.println("WiFi Disconnected");
}
//Send an HTTP POST request every 30 seconds
delay(30000);
}3. Open your serial monitor and you should get something like this.
Note: The link you should be inserting in the Arduino IDE serverName is the first link. I previously inserted the second link and it didn’t show any data.
4. Open your website (the second link) and it should show something like this. Mine was https://michellesbonusprojects.000webhostapp.com/esp32dataa.php
I checked my database and it also has the readings! :D
So yea, that’s the end of our ninth Embedded System Project: Insert ESP32 Data Into MySQL. (yeah!! 🥳) Stay tune for the next projects and stay safe and healthy 🥰