ESP32 Project #11: BMP180 Sensor Readings Visualization (MySQL + PHP)

Hello, I’m back. In this project I’ll show you how to visualize BMP180 sensor readings in a web server. To start, we will create a domain website on 000webhost.com. The tutorial can be found on my latest project:

After creating the site, go to Tools > Database Manager > Create Database.

Create Database

Remember the credentials since it will be used in the later part.

Go to Manage Database > PhpMyAdmin > id_ex_esp_data > SQL. Insert this SQL query below and click Go.

CREATE TABLE Sensor (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
value1 VARCHAR(10),
value2 VARCHAR(10),
value3 VARCHAR(10),
reading_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
)

If you’ve succeed creating the table, you’ll find the table in the Structure.

Create Table ‘Sensor’ Success

After that, we’re done with SQL. Let’s move to the PHP script.

Go back to the 000webhost dashboard and go to File Manager > Upload Files. Make sure to click public_html to upload the PHP script.

Copy this script to a text editor and upload it to the public_html folder. You can also add a new file by clicking the ‘New File’ icon in File Manager.

<?php
/*
Rui Santos
Complete project details at https://RandomNerdTutorials.com

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 = "id16568877_ex_esp_data";
// REPLACE with Database user
$username = "id16568877_ex_esp_board";
// 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 = $value1 = $value2 = $value3 = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
$api_key = test_input($_POST["api_key"]);
if($api_key == $api_key_value) {
$value1 = test_input($_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 Sensor (value1, value2, value3)
VALUES ('" . $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;
}
Upload PHP Script

Don’t forget to change the database credentials (with the ID). Don’t make the same mistake like me on my latest project :)

// Your Database name 
$dbname = "id_ex_esp_data";
// Your Database user
$username = "id_ex_esp_board";
// Your Database user password
$password = "password";

After saving the script, go to the site and this will appear.

Site

Go back to File Manager and upload a new PHP script to visualize data using chart.

PHP script to visualize data

Don’t forget to change the database credentials (with the ID). Copy this script and save the file.

<!--
Rui Santos
Complete project details at https://RandomNerdTutorials.com

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.
-->
<?php
$servername = "localhost";// REPLACE with your Database name
$dbname = "id16568877_ex_esp_data";
// REPLACE with Database user
$username = "id16568877_ex_esp_board";
// REPLACE with Database user password
$password = "password";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, value1, value2, value3, reading_time FROM Sensor order by reading_time desc limit 40";$result = $conn->query($sql);while ($data = $result->fetch_assoc()){
$sensor_data[] = $data;
}
$readings_time = array_column($sensor_data, 'reading_time');// ******* Uncomment to convert readings time array to your timezone ********
/*$i = 0;
foreach ($readings_time as $reading){
// Uncomment to set timezone to - 1 hour (you can change 1 to any number)
$readings_time[$i] = date("Y-m-d H:i:s", strtotime("$reading - 1 hours"));
// Uncomment to set timezone to + 4 hours (you can change 4 to any number)
//$readings_time[$i] = date("Y-m-d H:i:s", strtotime("$reading + 4 hours"));
$i += 1;
}*/
$value1 = json_encode(array_reverse(array_column($sensor_data, 'value1')), JSON_NUMERIC_CHECK);
$value2 = json_encode(array_reverse(array_column($sensor_data, 'value2')), JSON_NUMERIC_CHECK);
$value3 = json_encode(array_reverse(array_column($sensor_data, 'value3')), JSON_NUMERIC_CHECK);
$reading_time = json_encode(array_reverse($readings_time), JSON_NUMERIC_CHECK);
/*echo $value1;
echo $value2;
echo $value3;
echo $reading_time;*/
$result->free();
$conn->close();
?>
<!DOCTYPE html>
<html>
<meta name="viewport" content="width=device-width, initial-scale=1">
<script src="https://code.highcharts.com/highcharts.js"></script>
<style>
body {
min-width: 310px;
max-width: 1280px;
height: 500px;
margin: 0 auto;
}
h2 {
font-family: Arial;
font-size: 2.5rem;
text-align: center;
}
</style>
<body>
<h2>ESP Weather Station</h2>
<div id="chart-temperature" class="container"></div>
<div id="chart-humidity" class="container"></div>
<div id="chart-pressure" class="container"></div>
<script>
var value1 = <?php echo $value1; ?>;
var value2 = <?php echo $value2; ?>;
var value3 = <?php echo $value3; ?>;
var reading_time = <?php echo $reading_time; ?>;
var chartT = new Highcharts.Chart({
chart:{ renderTo : 'chart-temperature' },
title: { text: 'BME280 Temperature' },
series: [{
showInLegend: false,
data: value1
}],
plotOptions: {
line: { animation: false,
dataLabels: { enabled: true }
},
series: { color: '#059e8a' }
},
xAxis: {
type: 'datetime',
categories: reading_time
},
yAxis: {
title: { text: 'Temperature (Celsius)' }
//title: { text: 'Temperature (Fahrenheit)' }
},
credits: { enabled: false }
});
var chartH = new Highcharts.Chart({
chart:{ renderTo:'chart-humidity' },
title: { text: 'BME280 Humidity' },
series: [{
showInLegend: false,
data: value2
}],
plotOptions: {
line: { animation: false,
dataLabels: { enabled: true }
}
},
xAxis: {
type: 'datetime',
//dateTimeLabelFormats: { second: '%H:%M:%S' },
categories: reading_time
},
yAxis: {
title: { text: 'Humidity (%)' }
},
credits: { enabled: false }
});
var chartP = new Highcharts.Chart({
chart:{ renderTo:'chart-pressure' },
title: { text: 'BME280 Pressure' },
series: [{
showInLegend: false,
data: value3
}],
plotOptions: {
line: { animation: false,
dataLabels: { enabled: true }
},
series: { color: '#18009c' }
},
xAxis: {
type: 'datetime',
categories: reading_time
},
yAxis: {
title: { text: 'Pressure (hPa)' }
},
credits: { enabled: false }
});
</script>
</body>
</html>

Go to the site and this will appear.

Chart Site

After setting up the domain, database and PHP script, finally we will do the ESP32 part.

On this project, we’ll need:

  • ESP32 board
  • BMP180 sensor
  • Arduino IDE
  • Breadboard
  • Jumper wires
  • USB cable

This project’s schematic is still the same as the recent project:

BMP180 — ESP32

  • GND — GND
  • VCC — VIN
  • SDA — GPIO 21
  • SCL — GPIO 22
Wiring

Prepare the Arduino IDE and just copy the code from the last project. Don’t forget to change the SSID and password, and the serverName.

/*
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.

*/

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

#include <Wire.h>
#include <Adafruit_BMP085.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://chintyaw.000webhostapp.com/post-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 = "BMP180";
String sensorLocation = "Home";

#define SEALEVELPRESSURE_HPA (1013.25)

Adafruit_BMP085 bmp; // I2C

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 = bmp.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(bmp.readTemperature())
+ "&value2=" + String(bmp.readAltitude()) + "&value3=" + String(bmp.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 BMP180 sensor)
//String httpRequestData = "api_key=tPmAT5Ab3j7F9&sensor=BMP180&location=Home&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);
}Adafruit_BMP085 bmp;

// 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);
}

Verify and run. Open the Serial Monitor at 115200 baud rate and this should appear.

Serial Monitor

The sensor worked fine.

After that, let’s check the site.

http://chintyaw.000webhostapp.com/esp-chart.php

This appeared.

Yay, it worked fine!

In this project I learned about data visualization using chart on the web domain from the last project. Hope this story can help and stay tune for the next stories~

Learner || Product and UX enthusiast