DIYables ESP32 Web Apps Web Temperature
Overview
The WebTemperature example creates a visual thermometer interface accessible from any web browser. Designed for ESP32 educational platform with enhanced sensor monitoring capabilities, built-in temperature sensing features, and seamless integration with environmental monitoring educational modules. Perfect for monitoring temperature sensors, environmental conditions, or any temperature-based measurements requiring visual feedback.
Features
- Visual Thermometer Display: Interactive thermometer via web interface
- Configurable Temperature Range: Custom minimum and maximum temperatures with units
- Real-time Updates: Live temperature display with mercury-style animation
- Multiple Units Support: Celsius (°C), Fahrenheit (°F), Kelvin (K)
- Automatic Config Handling: Set range and unit once in constructor
- WebSocket Communication: Instant updates without page refresh
- Mobile Responsive: Works perfectly on desktop, tablet, and mobile devices
- Professional Design: Clean thermometer visualization with smooth animations
Hardware Used In This Tutorial
Or you can buy the following kits:
| 1 | × | DIYables ESP32 Starter Kit (ESP32 included) | |
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links in this section are Amazon affiliate links, meaning we may earn a commission at no additional cost to you if you make a purchase through them. Additionally, some links direct you to products from our own brand, DIYables .
Buy Note: Numerous DS18B20 sensors available in the market are of poor quality. We strongly advise purchasing the sensor from the DIYables brand via the link above; we conducted tests, and it performed reliably.
Setup Instructions
Quick Instructions
Follow these instructions step by step:
- If this is your first time using the ESP32, refer to the tutorial on setting up the environment for ESP32 in the Arduino IDE.
- Connect the ESP32 board to your computer using a USB cable.
- Launch the Arduino IDE on your computer.
- Select the appropriate ESP32 board (e.g. ESP32 Dev Module) and COM port.
- Navigate to the Libraries icon on the left bar of the Arduino IDE.
- Search "DIYables ESP32 WebApps", then find the DIYables ESP32 WebApps Library by DIYables
- Click Install button to install the library.
- You will be asked for installing some other library dependencies
- Click Install All button to install all library dependencies.
- On Arduino IDE, Go to File Examples DIYables ESP32 WebApps WebTemperature example, or copy the above code and paste it to the editor of Arduino IDE
/*
* This example demonstrates how to create a web-base Serial.println("Starting Web Temperature Server...");
// Add web apps to server
server.addApp(&homePage);
server.addApp(&temperaturePage);
// Set 404 Not Found page (optional - for better user experience)
server.setNotFoundPage(DIYablesNotFoundPage());re display
* using the DIYables ESP32 WebApps Library with ESP32.
*
* The library automatically detects the ESP32 platform and
* includes the appropriate abstraction layer for seamless operation.
*
* The web page displays a thermometer visualization that shows temperature
* readings in real-time through WebSocket communication.
*
* Features:
* - Real-time temperature display with thermometer visualization
* - Configurable temperature range and units
* - Auto-connecting WebSocket for seamless communication
* - Mobile-responsive design with professional UI
* - Automatic platform detection and abstraction
* - Compatible with both WiFi and Ethernet connections
* Hardware: ESP32 Boards
*/
#include <DIYables_ESP32_Platform.h>
#include <DIYablesWebApps.h>
// WiFi credentials - UPDATE THESE WITH YOUR NETWORK
const char WIFI_SSID[] = "YOUR_WIFI_SSID";
const char WIFI_PASSWORD[] = "YOUR_WIFI_PASSWORD";
// Create web app instances
ESP32ServerFactory serverFactory;
DIYablesWebAppServer server(serverFactory, 80, 81); // HTTP port 80, WebSocket port 81
DIYablesHomePage homePage;
DIYablesWebTemperaturePage temperaturePage(-10.0, 50.0, "°C"); // Min: -10°C, Max: 50°C
// Temperature simulation variables
float currentTemp = 25.0; // Starting temperature
unsigned long lastUpdate = 0;
void setup() {
Serial.begin(9600);
Serial.println("Starting Web Temperature Server...");
// Add web apps to server
server.addApp(&homePage);
server.addApp(&temperaturePage);
// Set 404 Not Found page (optional - for better user experience)
server.setNotFoundPage(DIYablesNotFoundPage());
// Set up temperature callback for value requests
temperaturePage.onTemperatureValueRequested(onTemperatureValueRequested);
// Start the server
server.begin(WIFI_SSID, WIFI_PASSWORD);
}
void loop() {
// Handle web server and WebSocket communications
server.loop();
// Simulate temperature readings
simulateTemperature();
// Send temperature update every 2 seconds
if (millis() - lastUpdate >= 2000) {
temperaturePage.sendTemperature(currentTemp);
// Print temperature to Serial Monitor
Serial.println("Temperature: " + String(currentTemp, 1) + "°C");
lastUpdate = millis();
}
delay(10); // Small delay for stability
}
void simulateTemperature() {
// Simple temperature simulation - slowly increases and decreases
static bool increasing = true;
if (increasing) {
currentTemp += 0.1; // Increase temperature slowly
if (currentTemp >= 35.0) {
increasing = false; // Start decreasing when it reaches 35°C
}
} else {
currentTemp -= 0.1; // Decrease temperature slowly
if (currentTemp <= 15.0) {
increasing = true; // Start increasing when it reaches 15°C
}
}
}
/**
* Callback function called when web interface requests temperature value
* Send current temperature value to web interface
*/
void onTemperatureValueRequested() {
Serial.println("Temperature value requested from web interface");
// Send current temperature value (config is automatically sent by the library)
temperaturePage.sendTemperature(currentTemp);
}
/*
* Alternative setup for real temperature sensor (DS18B20 example):
*
* #include <OneWire.h>
* #include <DallasTemperature.h>
*
* #define ONE_WIRE_BUS 2
* OneWire oneWire(ONE_WIRE_BUS);
* DallasTemperature sensors(&oneWire);
*
* void setup() {
* // ... existing setup code ...
* sensors.begin();
* }
*
* float readTemperature() {
* sensors.requestTemperatures();
* return sensors.getTempCByIndex(0);
* }
*
* // In loop(), replace simulateTemperature() with:
* // currentTemp = readTemperature();
*/
- Configure WiFi credentials in the code by updating these lines:
const char WIFI_SSID[] = "YOUR_WIFI_NETWORK";
const char WIFI_PASSWORD[] = "YOUR_WIFI_PASSWORD";
- Click Upload button on Arduino IDE to upload code to ESP32
- Open the Serial Monitor
- Check out the result on Serial Monitor. It looks like the below
COM6
Starting Web Temperature Server...
INFO: Added app /
INFO: Added app /web-temperature
DIYables WebApp Library
Platform: ESP32
Network connected!
IP address: 192.168.0.2
HTTP server started on port 80
Configuring WebSocket server callbacks...
WebSocket server started on port 81
WebSocket URL: ws://192.168.0.2:81
WebSocket server started on port 81
==========================================
DIYables WebApp Ready!
==========================================
📱 Web Interface: http://192.168.0.2
🔗 WebSocket: ws://192.168.0.2:81
📋 Available Applications:
🏠 Home Page: http://192.168.0.2/
🌡️ Web Temperature: http://192.168.0.2/web-temperature
==========================================
Autoscroll
Clear output
9600 baud
Newline
- If you do not see anything, reboot ESP32 board.
- Open a web browser on your PC or mobile phone.
- Type the IP address shown in the Serial Monitor to the web browser
- Example: http://192.168.1.100
- You will see the home page like below image:
- Click to the Web Temperature link, you will see the Web Temperature app's UI like the below:
- Or you can also access the page directly by IP address followed by /web-temperature. For example: http://192.168.1.100/web-temperature
- You will see a visual thermometer display showing real-time temperature readings
Web Interface Features
Thermometer Display
- Visual Thermometer: Classic thermometer design with mercury-style animation
- Temperature Scale: Clear scale markings with configurable range
- Real-time Updates: Live temperature display with smooth transitions
- Unit Display: Shows configured temperature units (°C, °F, K)
- Professional Design: Clean, educational-style thermometer visualization
Real-time Monitoring
- Live Data: Temperature updates automatically via WebSocket connection
- Smooth Animation: Mercury level moves smoothly between readings
- Status Feedback: Connection status indicator
- Mobile Optimized: Touch-friendly interface for all devices
Code Configuration
Temperature Setup
// Configure temperature range and units
DIYablesWebTemperaturePage temperaturePage(-10.0, 50.0, "°C"); // -10 to 50°C
// Set up temperature value request callback
temperaturePage.onTemperatureValueRequested(onTemperatureValueRequested);
Sending Temperature Values
void onTemperatureValueRequested() {
// Read temperature from sensor (example with simulation)
float currentTemp = readTemperatureSensor();
// Send to thermometer display
temperaturePage.sendTemperature(currentTemp);
}
Temperature Sensor Integration
DS18B20 Digital Temperature Sensor
#include <OneWire.h>
#include <DallasTemperature.h>
#define ONE_WIRE_BUS 2
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
void setup() {
sensors.begin();
// Configure temperature page for sensor range
DIYablesWebTemperaturePage tempPage(-55.0, 125.0, "°C");
}
float readTemperatureSensor() {
sensors.requestTemperatures();
return sensors.getTempCByIndex(0);
}
DHT22 Temperature/Humidity Sensor
#include <DHT.h>
#define DHT_PIN 2
#define DHT_TYPE DHT22
DHT dht(DHT_PIN, DHT_TYPE);
void setup() {
dht.begin();
// Configure for DHT22 range
DIYablesWebTemperaturePage tempPage(-40.0, 80.0, "°C");
}
float readTemperatureSensor() {
return dht.readTemperature(); // Returns °C
}
Analog Temperature Sensor (TMP36)
#define TEMP_PIN A0
float readTemperatureSensor() {
int reading = analogRead(TEMP_PIN);
float voltage = reading * 5.0 / 1024.0;
float temperatureC = (voltage - 0.5) * 100.0; // TMP36 formula
return temperatureC;
}
Unit Conversion
Supporting Multiple Units
// Temperature in different units
DIYablesWebTemperaturePage celsiusPage(-10.0, 50.0, "°C");
DIYablesWebTemperaturePage fahrenheitPage(14.0, 122.0, "°F");
DIYablesWebTemperaturePage kelvinPage(263.15, 323.15, "K");
// Conversion functions
float celsiusToFahrenheit(float celsius) {
return (celsius * 9.0/5.0) + 32.0;
}
float celsiusToKelvin(float celsius) {
return celsius + 273.15;
}
Customization Options
Temperature Range
- Minimum Temperature: Set lowest expected reading
- Maximum Temperature: Set highest expected reading
- Units: Display unit string (°C, °F, K, or custom)
- Scale: Thermometer scale automatically adjusts to range
Update Frequency
// Control update rate to avoid overwhelming the interface
unsigned long lastUpdate = 0;
const unsigned long UPDATE_INTERVAL = 1000; // 1 second
void loop() {
server.loop();
if (millis() - lastUpdate >= UPDATE_INTERVAL) {
// Update temperature display
lastUpdate = millis();
}
}
Common Use Cases
Educational Projects
- Weather Monitoring: Indoor/outdoor temperature tracking
- Physics Experiments: Heat transfer, thermal dynamics
- Environmental Science: Climate monitoring, greenhouse control
- Electronics Learning: Sensor interfacing, data visualization
Practical Applications
- Home Automation: HVAC control, energy monitoring
- Greenhouse Control: Plant growth optimization
- Food Safety: Temperature monitoring for storage
- Industrial: Process monitoring, quality control
Troubleshooting
Temperature Not Updating
- Check WiFi connection and WebSocket status
- Verify sensor wiring and power supply
- Ensure callback function is properly set
- Check Serial Monitor for sensor readings
Incorrect Temperature Values
- Verify sensor calibration and accuracy
- Check voltage reference for analog sensors
- Ensure proper sensor initialization
- Test sensor independently with basic code
Sensor Connection Issues
- Check wiring connections (power, ground, data)
- Verify pull-up resistors for digital sensors
- Test sensor with multimeter for proper operation
- Check sensor library installation and compatibility
Advanced Features
Multiple Temperature Sensors
Monitor multiple locations with separate thermometers:
DIYablesWebTemperaturePage indoorTemp(-10.0, 40.0, "°C");
DIYablesWebTemperaturePage outdoorTemp(-30.0, 50.0, "°C");
DIYablesWebTemperaturePage waterTemp(0.0, 100.0, "°C");
server.addApp(&indoorTemp);
server.addApp(&outdoorTemp);
server.addApp(&waterTemp);
Temperature Logging
Combine with Web Plotter for historical temperature data:
// Send same value to both thermometer and plotter
temperaturePage.sendTemperature(currentTemp);
plotterPage.sendData("Temperature", currentTemp);
Alert System
Implement temperature alerts:
void checkTemperatureAlerts(float temp) {
if (temp > 35.0) {
Serial.println("⚠️ High temperature alert!");
// Send alert via web interface
} else if (temp < 5.0) {
Serial.println("🧊 Low temperature alert!");
// Send alert via web interface
}
}
Educational Integration
STEM Learning Objectives
- Temperature Physics: Understanding thermal concepts
- Sensor Technology: Learning digital and analog sensors
- Data Visualization: Real-time data display techniques
- Programming: Callback functions, sensor integration
Classroom Activities
- Sensor Comparison: Compare different temperature sensor types
- Calibration Exercise: Learn measurement accuracy principles
- Environmental Monitoring: Track temperature changes over time
- System Integration: Combine with other environmental sensors
Science Experiments
- Heat Transfer: Monitor temperature changes during experiments
- Phase Changes: Observe temperature during melting/boiling
- Insulation Testing: Compare insulation effectiveness
- Climate Study: Long-term temperature monitoring
This example provides a comprehensive foundation for temperature monitoring and visualization, perfect for both educational and practical environmental monitoring applications.