Arduino Nano ESP32 - Web Apps Multiple Web Apps
Overview
This tutorial shows how to run several web application pages at the same time on an Arduino Nano ESP32 using the DIYables ESP32 WebApps Library. Each page is independent; you register only the ones your project requires. The home page lists all registered apps automatically.
What This Tutorial Covers
- Registering multiple page objects with one server instance
- Configuring state variables shared across pages
- Pre-configuring digital pin modes for the web digital pins page
- Configuring joystick sensitivity and auto-return from the sketch
- Navigating between pages from the home page
Hardware Preparation
Or you can buy the following kits:
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
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Additionally, some of these links are for products from our own brand, DIYables .
Additionally, some of these links are for products from our own brand, DIYables .
Steps
Follow these instructions step by step:
- If this is your first time using the Arduino Nano ESP32, refer to the tutorial on setting up the Arduino Nano ESP32 development environment.
- Connect the Arduino Nano ESP32 board to your computer using a USB cable.
- Launch the Arduino IDE on your computer.
- Select the appropriate board (e.g. Arduino Nano ESP32) 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.
- Search for DIYables ESP32 WebApps created by DIYables and click the Install button.
1
void setup() {
- 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 MultipleWebApps example, or copy the above code and paste it to the editor of Arduino IDE
/*
* DIYables WebApp Library - Multiple WebApps Example
*
* This example demonstrates multiple web apps of the DIYables WebApp library:
* - Home page with links to multiple web apps
* - Web Monitor: Real-time serial monitoring via WebSocket
* - Web Slider: Dual slider control
* - Web Joystick: Interactive joystick control
* - Web Rotator: Interactive rotatable disc control
* - Web Analog Gauge: Professional circular gauge for sensor monitoring
* - Web Table: Two-column data table with real-time updates
* - Web Plotter: See WebPlotter example for real-time data visualization
*
* Features:
* - Simplified callback system - no manual command parsing needed
* - Automatic state synchronization and JSON handling
* - All protocol details handled by the library
* - Template for hardware control
*
* Hardware: ESP32 Boards
*
* Setup:
* 1. Update WiFi credentials below
* 2. Upload the sketch to your Arduino
* 3. Open Serial Monitor to see the IP address
* 4. Navigate to the IP address in your web browser
*/
#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 WebApp server and page instances
ESP32ServerFactory factory;
DIYablesWebAppServer webAppsServer(factory, 80, 81);
DIYablesHomePage homePage;
DIYablesWebMonitorPage webMonitorPage;
DIYablesWebSliderPage webSliderPage;
DIYablesWebJoystickPage webJoystickPage(false, 5); // autoReturn=false, sensitivity=5
DIYablesWebRotatorPage webRotatorPage(ROTATOR_MODE_CONTINUOUS); // Continuous rotation mode (0-360°)
DIYablesWebAnalogGaugePage webAnalogGaugePage(0.0, 100.0, "%"); // Range: 0-100%, units: %
DIYablesWebTablePage webTablePage;
// Variables to track states
int currentSlider1 = 64; // Slider 1 value (0-255)
int currentSlider2 = 128; // Slider 2 value (0-255)
int currentJoystickX = 0; // Current joystick X value (-100 to 100)
int currentJoystickY = 0; // Current joystick Y value (-100 to 100)
int currentRotatorAngle = 0; // Current rotator angle (0-360°)
float currentGaugeValue = 50.0; // Current gauge value (0.0-100.0)
void setup() {
Serial.begin(9600);
delay(1000);
// TODO: Initialize your hardware pins here
Serial.println("DIYables ESP32 WebApp - Multiple Apps Example");
// Add all web applications to the server
webAppsServer.addApp(&homePage);
webAppsServer.addApp(&webMonitorPage);
webAppsServer.addApp(&webSliderPage);
webAppsServer.addApp(&webJoystickPage);
webAppsServer.addApp(&webRotatorPage);
webAppsServer.addApp(&webAnalogGaugePage);
webAppsServer.addApp(&webTablePage);
// Add more web apps here (e.g., WebPlotter)
// Set 404 Not Found page (optional - for better user experience)
webAppsServer.setNotFoundPage(DIYablesNotFoundPage());
// Configure table structure (only attribute names, values will be updated dynamically)
webTablePage.addRow("Arduino Status");
webTablePage.addRow("WiFi Connected");
webTablePage.addRow("Uptime");
webTablePage.addRow("Slider 1");
webTablePage.addRow("Slider 2");
webTablePage.addRow("Joystick X");
webTablePage.addRow("Joystick Y");
webTablePage.addRow("Rotator Angle");
webTablePage.addRow("Gauge Value");
// Start the WebApp server
if (!webAppsServer.begin(WIFI_SSID, WIFI_PASSWORD)) {
while (1) {
Serial.println("Failed to start WebApp server!");
delay(1000);
}
}
setupCallbacks();
}
void setupCallbacks() {
// Web Monitor callback - echo messages back
webMonitorPage.onWebMonitorMessage([](const String& message) {
Serial.println("Web Monitor: " + message);
webMonitorPage.sendToWebMonitor("Arduino received: " + message);
});
// Web Slider callback - handle slider values
webSliderPage.onSliderValueFromWeb([](int slider1, int slider2) {
// Store the received values
currentSlider1 = slider1;
currentSlider2 = slider2;
// Print slider values (0-255) without String concatenation
Serial.print("Slider 1: ");
Serial.print(slider1);
Serial.print(", Slider 2: ");
Serial.println(slider2);
// Update table with new slider values using String() conversion
webTablePage.sendValueUpdate("Slider 1", String(slider1));
webTablePage.sendValueUpdate("Slider 2", String(slider2));
// TODO: Add your control logic here based on slider values
// Examples:
// - Control PWM: analogWrite(LED_PIN, slider1);
// - Control servos: servo.write(map(slider1, 0, 255, 0, 180));
// - Control motor speed: analogWrite(MOTOR_PIN, slider2);
// Update gauge based on slider1 value (map 0-255 to 0-100)
currentGaugeValue = map(slider1, 0, 255, 0, 100);
webAnalogGaugePage.sendToWebAnalogGauge(currentGaugeValue);
char gaugeStr[16];
snprintf(gaugeStr, sizeof(gaugeStr), "%.1f%%", currentGaugeValue);
webTablePage.sendValueUpdate("Gauge Value", String(gaugeStr));
});
// Handle slider value requests
webSliderPage.onSliderValueToWeb([]() {
webSliderPage.sendToWebSlider(currentSlider1, currentSlider2);
});
// Web Joystick callback - handle joystick movement
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Store the received values
currentJoystickX = x;
currentJoystickY = y;
// Print joystick position values (-100 to +100)
Serial.print("Joystick - X: ");
Serial.print(x);
Serial.print(", Y: ");
Serial.println(y);
Serial.print(x);
Serial.print(", Y: ");
Serial.println(y);
// Update table with new joystick values
webTablePage.sendValueUpdate("Joystick X", String(x));
webTablePage.sendValueUpdate("Joystick Y", String(y));
// TODO: Add your control logic here based on joystick position
// Examples:
// - Control motors: if (x > 50) { /* move right */ }
// - Control servos: servo.write(map(y, -100, 100, 0, 180));
// - Control LEDs: analogWrite(LED_PIN, map(abs(x), 0, 100, 0, 255));
});
// Handle joystick values requests (when web page loads/reconnects)
webJoystickPage.onJoystickValueToWeb([]() {
webJoystickPage.sendToWebJoystick(currentJoystickX, currentJoystickY);
});
// Web Rotator callback - handle rotation angle changes
webRotatorPage.onRotatorAngleFromWeb([](float angle) {
// Store the received angle
currentRotatorAngle = (int)angle;
// Print rotator angle (0-360°)
Serial.println("Rotator angle: " + String(angle) + "°");
// Update table with new rotator angle
webTablePage.sendValueUpdate("Rotator Angle", String(angle, 0) + "°");
// TODO: Add your control logic here based on rotator angle
// Examples:
// - Control servo: servo.write(map(angle, 0, 360, 0, 180));
// - Control stepper motor: stepper.moveTo(angle);
// - Control directional LED strip: setLEDDirection(angle);
});
// Handle analog gauge value requests (when web page loads/reconnects)
webAnalogGaugePage.onGaugeValueRequest([]() {
webAnalogGaugePage.sendToWebAnalogGauge(currentGaugeValue);
});
// Handle table data requests (when web page loads/reconnects)
webTablePage.onTableValueRequest([]() {
// Send initial values to the table
webTablePage.sendValueUpdate("Arduino Status", "Running");
webTablePage.sendValueUpdate("WiFi Connected", "Yes");
webTablePage.sendValueUpdate("Uptime", "0 seconds");
webTablePage.sendValueUpdate("Slider 1", String(currentSlider1));
webTablePage.sendValueUpdate("Slider 2", String(currentSlider2));
webTablePage.sendValueUpdate("Joystick X", String(currentJoystickX));
webTablePage.sendValueUpdate("Joystick Y", String(currentJoystickY));
webTablePage.sendValueUpdate("Rotator Angle", String(currentRotatorAngle) + "°");
webTablePage.sendValueUpdate("Gauge Value", String(currentGaugeValue, 1) + "%");
});
}
void loop() {
// Handle WebApp server communications
webAppsServer.loop();
// Update table with current uptime every 5 seconds
static unsigned long lastUptimeUpdate = 0;
if (millis() - lastUptimeUpdate > 5000) {
lastUptimeUpdate = millis();
unsigned long uptimeSeconds = millis() / 1000;
String uptimeStr = String(uptimeSeconds) + " seconds";
if (uptimeSeconds >= 60) {
uptimeStr = String(uptimeSeconds / 60) + "m " + String(uptimeSeconds % 60) + "s";
}
webTablePage.sendValueUpdate("Uptime", uptimeStr);
}
// Simulate sensor data updates every 3 seconds
static unsigned long lastSensorUpdate = 0;
if (millis() - lastSensorUpdate > 3000) {
lastSensorUpdate = millis();
// Simulate a sensor reading that varies over time
float sensorValue = 50.0 + 30.0 * sin(millis() / 10000.0); // Oscillates between 20-80
currentGaugeValue = sensorValue;
// Update gauge and table
webAnalogGaugePage.sendToWebAnalogGauge(currentGaugeValue);
webTablePage.sendValueUpdate("Gauge Value", String(currentGaugeValue, 1) + "%");
}
// TODO: Add your main application code here
delay(10);
}
- Update the WiFi credentials in the sketch:
const char WIFI_SSID[] = "YOUR_WIFI_NETWORK";
const char WIFI_PASSWORD[] = "YOUR_WIFI_PASSWORD";
- Click Upload button on Arduino IDE to upload code to Arduino Nano ESP32
- Open the Serial Monitor
- The Serial Monitor output should resemble the following:
8
Serial.println("Hello World!");
Message (Enter to send message to 'Arduino Nano ESP32' on 'COM15')
New Line
9600 baud
DIYables WebApp - Multiple Apps Example
INFO: Added app /
INFO: Added app /web-monitor
INFO: Added app /web-slider
INFO: Added app /web-joystick
INFO: Added app /web-rotator
INFO: Added app /web-gauge
INFO: Added app /web-table
DIYables WebApp Library
Platform: Arduino Nano 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 Monitor: http://192.168.0.2/web-monitor
Web Slider: http://192.168.0.2/web-slider
Web Joystick: http://192.168.0.2/web-joystick
Web Rotator: http://192.168.0.2/web-rotator
Web Analog Gauge: http://192.168.0.2/web-gauge
Web Table: http://192.168.0.2/web-table
==========================================
- If nothing appears, press the reset button on the board.
- Note the IP address and enter it in a browser on a device connected to the same WiFi network.
- Example: http://192.168.0.2
- The home page shows cards for all registered applications:
- Select any card to open that application. Each page is also accessible directly by its path, for example http://192.168.0.2/web-monitor or http://192.168.0.2/web-slider.
Application URLs
| Application | URL Path | |
|---|---|---|
| Home Page | http | //[board-ip]/ |
| Web Monitor | http | //[board-ip]/web-monitor |
| Web Slider | http | //[board-ip]/web-slider |
| Web Joystick | http | //[board-ip]/web-joystick |
| Web Rotator | http | //[board-ip]/web-rotator |
| Web Analog Gauge | http | //[board-ip]/web-gauge |
| Web Table | http | //[board-ip]/web-table |
Configuration Details
Digital Pin Setup
Output pins are writable from the browser; input pins display their current state:
webDigitalPinsPage.enablePin(2, WEB_PIN_OUTPUT); // General output
webDigitalPinsPage.enablePin(3, WEB_PIN_OUTPUT); // General output
webDigitalPinsPage.enablePin(4, WEB_PIN_OUTPUT); // General output
webDigitalPinsPage.enablePin(13, WEB_PIN_OUTPUT); // Built-in LED
webDigitalPinsPage.enablePin(8, WEB_PIN_INPUT); // Sensor input
webDigitalPinsPage.enablePin(9, WEB_PIN_INPUT); // Switch input
Joystick Configuration
// autoReturn=false: joystick stays at released position
// sensitivity=5: updates only when movement exceeds 5%
DIYablesWebJoystickPage webJoystickPage(false, 5);
Shared State Variables
State variables keep all pages consistent with the actual hardware values:
int pinStates[16] = { LOW }; // Digital pin states for pins 0-13
int currentSlider1 = 64; // Slider 1 value (0-255), starts at 25%
int currentSlider2 = 128; // Slider 2 value (0-255), starts at 50%
int currentJoystickX = 0; // Last joystick X (-100 to 100)
int currentJoystickY = 0; // Last joystick Y (-100 to 100)
Built-in Chat Commands
The example sketch handles the following chat inputs:
- hello — Returns a greeting
- time — Reports board uptime in seconds
- status — Reports system status and LED state
- help — Lists recognized commands
- led on — Turns on the built-in LED
- led off — Turns off the built-in LED
Example exchange:
User: hello
ESP32: Hello! I'm your Arduino. How can I help you?
User: led on
ESP32: Built-in LED is now ON
User: time
ESP32: I've been running for 1245 seconds.
User: status
ESP32: Status: Running smoothly! LED is ON
Adapting the Example
Using Joystick with Motor Control
Map joystick X/Y values to left and right motor speeds using the callback:
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
int leftSpeed = constrain(y + (x / 2), -100, 100);
int rightSpeed = constrain(y - (x / 2), -100, 100);
// Scale by slider 1 for speed limiting
leftSpeed = map(leftSpeed, -100, 100, -currentSlider1, currentSlider1);
rightSpeed = map(rightSpeed, -100, 100, -currentSlider1, currentSlider1);
analogWrite(MOTOR_LEFT_PWM, abs(leftSpeed));
analogWrite(MOTOR_RIGHT_PWM, abs(rightSpeed));
});
Sending Sensor Data to the Monitor
Use the monitor page to display sensor readings instead of the Serial port:
void loop() {
webAppsServer.loop();
float temperature = readTemperature();
webMonitorPage.sendToWebMonitor("Temp: " + String(temperature) + " C");
delay(1000);
}
Memory Considerations
Each registered page increases flash and RAM usage. Remove pages not used by your project. The modular design means calling addApp() only for the pages you need is sufficient — unused page classes are not linked.
Refer to the memory reference table for per-component footprint estimates.