DIYables ESP32 Web Apps Multiple Web Apps
Overview
This example showcases how to use multiple web applications simultaneously with the DIYables ESP32 WebApps Library. It demonstrates the integration of several interactive web interfaces—such as monitoring, control, and communication—within a single project. Designed for the ESP32 platform, this example is ideal for learning how to combine and manage multiple web-based features at the same time, providing a robust foundation for advanced IoT projects.
Features
- Home Page: Central navigation hub with links to all web applications
- Web Monitor: Real-time serial communication and debugging interface
- Chat Interface: Interactive chat system with ESP32 response capabilities
- Digital Pin Control: Web-based control and monitoring of all digital pins
- Dual Slider Control: Two independent sliders for analog value control
- Virtual Joystick: 2D position control for directional applications
- Unified State Management: All interfaces share synchronized state information
- Real-time Updates: WebSocket communication for instant response
- Template Structure: Ready-to-customize foundation for complex projects
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 .
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 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);
}
- 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
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: 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
==========================================
Autoscroll
Clear output
9600 baud
Newline
- If you do not see anything, reboot ESP32 board.
- Take note of the IP address displayed, and enter this address into the address bar of a web browser on your smartphone or PC.
- Example: http://192.168.0.2
- You will see the home page with all web applications like below image:
- Click to any web application link (Chat, Web Monitor, Web Digital Pins, Web Slider, Web Joystick, etc.), you will see the corresponding web app's UI.
- Or you can also access each page directly by IP address followed by the app path. For example: http://192.168.0.2/chat, http://192.168.0.2/web-monitor, etc.
- Explore all the web applications: try chatting with Arduino, monitor serial output, control digital pins, adjust sliders, and use the virtual joystick to experience the full capabilities of the integrated web interface.
Creative Customization - Unleash Your Innovation
This comprehensive example provides a foundation for your creative projects. Modify and adapt the configurations below to build amazing IoT applications that match your unique vision.
Digital Pin Configuration
The example pre-configures specific pins for different purposes:
Output Pins (Controllable via Web)
webDigitalPinsPage.enablePin(2, WEB_PIN_OUTPUT); // General purpose output
webDigitalPinsPage.enablePin(3, WEB_PIN_OUTPUT); // General purpose output
webDigitalPinsPage.enablePin(4, WEB_PIN_OUTPUT); // General purpose output
webDigitalPinsPage.enablePin(13, WEB_PIN_OUTPUT); // Built-in LED
Input Pins (Monitored via Web)
webDigitalPinsPage.enablePin(8, WEB_PIN_INPUT); // Sensor input
webDigitalPinsPage.enablePin(9, WEB_PIN_INPUT); // Switch input
Joystick Configuration
// Create joystick with custom settings
// autoReturn=false: Joystick stays at last position when released
// sensitivity=5: Only send updates when movement > 5%
DIYablesWebJoystickPage webJoystickPage(false, 5);
State Variables
The example maintains synchronized state across all interfaces:
int pinStates[16] = { LOW }; // Track pin states (pins 0-13)
int currentSlider1 = 64; // Slider 1 value (0-255) - 25%
int currentSlider2 = 128; // Slider 2 value (0-255) - 50%
int currentJoystickX = 0; // Joystick X value (-100 to 100)
int currentJoystickY = 0; // Joystick Y value (-100 to 100)
Built-in Chat Commands
The chat interface includes several pre-programmed commands:
Basic Commands
- hello - Friendly greeting response
- time - Shows ESP32 uptime in seconds
- status - Reports ESP32 status and LED state
- help - Lists available commands
Control Commands
- led on - Turns on the built-in LED
- led off - Turns off the built-in LED
Example Chat Session
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
Programming Integration Examples
Complete Robot Control System
#include <Servo.h>
// Hardware definitions
const int MOTOR_LEFT_PWM = 9;
const int MOTOR_RIGHT_PWM = 10;
const int SERVO_PAN = 11;
const int SERVO_TILT = 12;
const int LED_STRIP_PIN = 6;
Servo panServo, tiltServo;
void setup() {
// Initialize hardware
panServo.attach(SERVO_PAN);
tiltServo.attach(SERVO_TILT);
pinMode(MOTOR_LEFT_PWM, OUTPUT);
pinMode(MOTOR_RIGHT_PWM, OUTPUT);
// ... WebApp setup code ...
setupRobotCallbacks();
}
void setupRobotCallbacks() {
// Use joystick for robot movement
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Convert joystick to tank drive
int leftSpeed = y + (x / 2);
int rightSpeed = y - (x / 2);
leftSpeed = constrain(leftSpeed, -100, 100);
rightSpeed = constrain(rightSpeed, -100, 100);
// Apply speed limits from sliders
leftSpeed = map(leftSpeed, -100, 100, -currentSlider1, currentSlider1);
rightSpeed = map(rightSpeed, -100, 100, -currentSlider1, currentSlider1);
// Control motors
analogWrite(MOTOR_LEFT_PWM, abs(leftSpeed));
analogWrite(MOTOR_RIGHT_PWM, abs(rightSpeed));
Serial.println("Robot - Left: " + String(leftSpeed) + ", Right: " + String(rightSpeed));
});
// Use sliders for camera pan/tilt control
webSliderPage.onSliderValueFromWeb([](int slider1, int slider2) {
// Slider 1 controls maximum speed, Slider 2 controls camera tilt
int panAngle = map(currentJoystickX, -100, 100, 0, 180);
int tiltAngle = map(slider2, 0, 255, 0, 180);
panServo.write(panAngle);
tiltServo.write(tiltAngle);
Serial.println("Camera - Pan: " + String(panAngle) + "°, Tilt: " + String(tiltAngle) + "°");
});
// Use digital pins for special functions
webDigitalPinsPage.onPinWrite([](int pin, int state) {
switch (pin) {
case 2: // Headlights
digitalWrite(pin, state);
Serial.println("Headlights " + String(state ? "ON" : "OFF"));
break;
case 3: // Horn/Buzzer
if (state) {
// Trigger buzzer sequence
digitalWrite(pin, HIGH);
delay(200);
digitalWrite(pin, LOW);
}
break;
case 4: // Emergency stop
if (state) {
analogWrite(MOTOR_LEFT_PWM, 0);
analogWrite(MOTOR_RIGHT_PWM, 0);
Serial.println("EMERGENCY STOP ACTIVATED");
}
break;
}
});
// Enhanced chat commands for robot control
chatPage.onChatMessage([](const String& message) {
String msg = message;
msg.toLowerCase();
if (msg.indexOf("stop") >= 0) {
analogWrite(MOTOR_LEFT_PWM, 0);
analogWrite(MOTOR_RIGHT_PWM, 0);
chatPage.sendToChat("Robot stopped!");
return;
}
if (msg.indexOf("center camera") >= 0) {
panServo.write(90);
tiltServo.write(90);
chatPage.sendToChat("Camera centered!");
return;
}
if (msg.indexOf("speed") >= 0) {
String response = "Current max speed: " + String(map(currentSlider1, 0, 255, 0, 100)) + "%";
chatPage.sendToChat(response);
return;
}
// Default response for unknown commands
chatPage.sendToChat("Robot commands: stop, center camera, speed");
});
}
Smart Home Control System
// Home automation pin assignments
const int LIVING_ROOM_LIGHTS = 2;
const int BEDROOM_LIGHTS = 3;
const int KITCHEN_LIGHTS = 4;
const int FAN_CONTROL = 9;
const int AC_CONTROL = 10;
const int MOTION_SENSOR = 8;
const int DOOR_SENSOR = 9;
void setupHomeAutomation() {
// Configure home automation pins
pinMode(LIVING_ROOM_LIGHTS, OUTPUT);
pinMode(BEDROOM_LIGHTS, OUTPUT);
pinMode(KITCHEN_LIGHTS, OUTPUT);
pinMode(FAN_CONTROL, OUTPUT);
pinMode(AC_CONTROL, OUTPUT);
pinMode(MOTION_SENSOR, INPUT);
pinMode(DOOR_SENSOR, INPUT_PULLUP);
// Digital pins for room lighting control
webDigitalPinsPage.onPinWrite([](int pin, int state) {
digitalWrite(pin, state);
String room;
switch (pin) {
case 2: room = "Living Room"; break;
case 3: room = "Bedroom"; break;
case 4: room = "Kitchen"; break;
default: room = "Pin " + String(pin); break;
}
Serial.println(room + " lights " + String(state ? "ON" : "OFF"));
// Send notification to chat
String message = room + " lights turned " + String(state ? "ON" : "OFF");
chatPage.sendToChat(message);
});
// Sliders for fan and AC control
webSliderPage.onSliderValueFromWeb([](int slider1, int slider2) {
// Slider 1 controls fan speed (0-255)
analogWrite(FAN_CONTROL, slider1);
// Slider 2 controls AC intensity (0-255)
analogWrite(AC_CONTROL, slider2);
Serial.println("Fan: " + String(map(slider1, 0, 255, 0, 100)) + "%, " +
"AC: " + String(map(slider2, 0, 255, 0, 100)) + "%");
});
// Enhanced chat commands for home control
chatPage.onChatMessage([](const String& message) {
String msg = message;
msg.toLowerCase();
if (msg.indexOf("all lights on") >= 0) {
digitalWrite(LIVING_ROOM_LIGHTS, HIGH);
digitalWrite(BEDROOM_LIGHTS, HIGH);
digitalWrite(KITCHEN_LIGHTS, HIGH);
chatPage.sendToChat("All lights turned ON!");
return;
}
if (msg.indexOf("all lights off") >= 0) {
digitalWrite(LIVING_ROOM_LIGHTS, LOW);
digitalWrite(BEDROOM_LIGHTS, LOW);
digitalWrite(KITCHEN_LIGHTS, LOW);
chatPage.sendToChat("All lights turned OFF!");
return;
}
if (msg.indexOf("temperature") >= 0) {
String response = "Fan: " + String(map(currentSlider1, 0, 255, 0, 100)) + "%, " +
"AC: " + String(map(currentSlider2, 0, 255, 0, 100)) + "%";
chatPage.sendToChat(response);
return;
}
if (msg.indexOf("security") >= 0) {
bool motion = digitalRead(MOTION_SENSOR);
bool door = digitalRead(DOOR_SENSOR);
String status = "Motion: " + String(motion ? "DETECTED" : "CLEAR") +
", Door: " + String(door ? "CLOSED" : "OPEN");
chatPage.sendToChat(status);
return;
}
// Default home automation help
chatPage.sendToChat("Home commands: all lights on/off, temperature, security");
});
}
void loop() {
server.loop();
// Monitor home security sensors
static bool lastMotion = false;
static bool lastDoor = false;
bool currentMotion = digitalRead(MOTION_SENSOR);
bool currentDoor = digitalRead(DOOR_SENSOR);
// Send alerts for security events
if (currentMotion != lastMotion) {
if (currentMotion) {
chatPage.sendToChat("🚨 MOTION DETECTED!");
webMonitorPage.sendToWebMonitor("Security Alert: Motion detected");
}
lastMotion = currentMotion;
}
if (currentDoor != lastDoor) {
String status = currentDoor ? "CLOSED" : "OPENED";
chatPage.sendToChat("🚪 Door " + status);
webMonitorPage.sendToWebMonitor("Security: Door " + status);
lastDoor = currentDoor;
}
delay(10);
}
Educational Science Project
// Science experiment control system
const int HEATING_ELEMENT = 9;
const int COOLING_FAN = 10;
const int STIRRER_MOTOR = 11;
const int TEMP_SENSOR_PIN = A0;
const int PH_SENSOR_PIN = A1;
void setupScienceExperiment() {
// Sliders for temperature and stirring control
webSliderPage.onSliderValueFromWeb([](int slider1, int slider2) {
// Slider 1 controls target temperature (mapped to heating/cooling)
int targetTemp = map(slider1, 0, 255, 20, 80); // 20-80°C range
// Slider 2 controls stirrer speed
analogWrite(STIRRER_MOTOR, slider2);
// Simple temperature control logic
int currentTemp = readTemperature();
if (currentTemp < targetTemp) {
analogWrite(HEATING_ELEMENT, 200); // Heat on
analogWrite(COOLING_FAN, 0); // Fan off
} else if (currentTemp > targetTemp + 2) {
analogWrite(HEATING_ELEMENT, 0); // Heat off
analogWrite(COOLING_FAN, 255); // Fan on
} else {
analogWrite(HEATING_ELEMENT, 0); // Both off (maintain)
analogWrite(COOLING_FAN, 0);
}
Serial.println("Target: " + String(targetTemp) + "°C, Current: " + String(currentTemp) + "°C");
});
// Chat interface for experiment control and data
chatPage.onChatMessage([](const String& message) {
String msg = message;
msg.toLowerCase();
if (msg.indexOf("data") >= 0) {
int temp = readTemperature();
float ph = readPH();
String data = "Temperature: " + String(temp) + "°C, pH: " + String(ph, 2);
chatPage.sendToChat(data);
return;
}
if (msg.indexOf("start") >= 0) {
// Begin experiment sequence
chatPage.sendToChat("🔬 Experiment started! Monitoring conditions...");
return;
}
if (msg.indexOf("stop") >= 0) {
// Emergency stop
analogWrite(HEATING_ELEMENT, 0);
analogWrite(COOLING_FAN, 0);
analogWrite(STIRRER_MOTOR, 0);
chatPage.sendToChat("⚠️ Experiment stopped - all systems OFF");
return;
}
chatPage.sendToChat("Science commands: data, start, stop");
});
// Monitor for automatic data logging
webMonitorPage.onWebMonitorMessage([](const String& message) {
if (message == "log") {
int temp = readTemperature();
float ph = readPH();
String logEntry = String(millis()) + "," + String(temp) + "," + String(ph, 2);
webMonitorPage.sendToWebMonitor(logEntry);
}
});
}
int readTemperature() {
// Read temperature sensor (example implementation)
int sensorValue = analogRead(TEMP_SENSOR_PIN);
return map(sensorValue, 0, 1023, 0, 100); // Convert to temperature
}
float readPH() {
// Read pH sensor (example implementation)
int sensorValue = analogRead(PH_SENSOR_PIN);
return map(sensorValue, 0, 1023, 0, 14) / 10.0; // Convert to pH
}
Advanced Integration Techniques
State Synchronization
void synchronizeAllStates() {
// Ensure all interfaces show current state
webSliderPage.sendToWebSlider(currentSlider1, currentSlider2);
webJoystickPage.sendToWebJoystick(currentJoystickX, currentJoystickY);
// Update all pin states
for (int pin = 0; pin <= 13; pin++) {
if (webDigitalPinsPage.isPinEnabled(pin)) {
webDigitalPinsPage.updatePinState(pin, pinStates[pin]);
}
}
Serial.println("All interface states synchronized");
}
Cross-Interface Communication
void setupCrossInterfaceCommunication() {
// Joystick position affects slider maximum values
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Calculate distance from center
float distance = sqrt(x*x + y*y);
// Limit slider maximum based on joystick distance
if (distance > 50) {
// Reduce maximum slider values when joystick is far from center
int maxValue = map(distance, 50, 100, 255, 128);
// You could implement dynamic slider limiting here
}
});
// Pin states affect available chat commands
webDigitalPinsPage.onPinWrite([](int pin, int state) {
if (pin == 2 && state == HIGH) {
chatPage.sendToChat("📢 System armed - additional commands available");
} else if (pin == 2 && state == LOW) {
chatPage.sendToChat("📢 System disarmed - limited commands only");
}
});
}
Troubleshooting
Common Issues
1. Some interfaces not loading
- Check that all applications are added to server in setup()
- Verify WebSocket connections in browser console
- Ensure sufficient memory for all interfaces
2. State inconsistencies between interfaces
- Implement state synchronization callbacks
- Use shared global variables for state tracking
- Call synchronization functions after major state changes
3. Performance issues with multiple interfaces
- Reduce update frequencies for non-critical interfaces
- Implement selective updates based on active interface
- Consider disabling unused interfaces for specific projects
4. Memory limitations
- Monitor available RAM with Serial.print(freeMemory())
- Disable unused interfaces if memory is tight
- Optimize callback functions to minimize memory usage
Debug Strategies
void debugSystemState() {
Serial.println("=== System State Debug ===");
Serial.println("Free Memory: " + String(freeMemory()) + " bytes");
Serial.println("Digital Pins:");
for (int pin = 0; pin <= 13; pin++) {
if (webDigitalPinsPage.isPinEnabled(pin)) {
Serial.println(" Pin " + String(pin) + ": " + String(pinStates[pin] ? "HIGH" : "LOW"));
}
}
Serial.println("Sliders: " + String(currentSlider1) + ", " + String(currentSlider2));
Serial.println("Joystick: X=" + String(currentJoystickX) + ", Y=" + String(currentJoystickY));
Serial.println("========================");
}
Project Templates
Industrial Control Template
- Digital pins for machinery control
- Sliders for speed/temperature control
- Joystick for positioning systems
- Chat for status reporting and commands
- Monitor for data logging
Educational Laboratory Template
- Sliders for experiment parameters
- Digital pins for equipment control
- Chat for student interaction
- Monitor for data collection
- Real-time sensor monitoring
Home Automation Template
- Digital pins for lighting/appliance control
- Sliders for dimming and climate control
- Security monitoring via input pins
- Chat for voice-like commands
- Monitor for system status logging
Robotics Development Template
- Joystick for movement control
- Sliders for speed and servo positioning
- Digital pins for sensor inputs
- Chat for command interface
- Monitor for debugging and telemetry
Performance Optimization
Memory Management
void optimizeMemoryUsage() {
// Disable unused interfaces to save memory
// server.addApp(&homePage); // Always keep home page
// server.addApp(&webMonitorPage); // Keep for debugging
// server.addApp(&chatPage); // Optional
// server.addApp(&webDigitalPinsPage); // Based on project needs
// server.addApp(&webSliderPage); // Based on project needs
// server.addApp(&webJoystickPage); // Based on project needs
}
Update Frequency Control
void controlUpdateFrequency() {
static unsigned long lastSlowUpdate = 0;
static unsigned long lastFastUpdate = 0;
// Fast updates for critical controls (10ms)
if (millis() - lastFastUpdate > 10) {
// Update joystick and emergency controls
lastFastUpdate = millis();
}
// Slow updates for monitoring (1000ms)
if (millis() - lastSlowUpdate > 1000) {
// Update sensor readings and status
lastSlowUpdate = millis();
}
}
Next Steps
After mastering the MultipleWebApps example:
- Customize for Your Project: Remove unused interfaces and add project-specific logic
- Add Sensors: Integrate real sensor readings for input monitoring
- Implement Safety: Add emergency stops and safety interlocks
- Create Custom Commands: Extend chat interface with project-specific commands
- Add Data Logging: Use web monitor for permanent data storage
- Mobile Optimization: Test and optimize for mobile device usage
Support
For additional help:
- Check individual example documentation (Chat_Example.txt, WebMonitor_Example.txt, etc.)
- Review the API Reference documentation
- Visit DIYables tutorials: https://esp32io.com/tutorials/diyables-esp32-webapps
- ESP32 community forums
This comprehensive example provides the foundation for virtually any web-controlled ESP32 project. Start with this template and customize it for your specific needs!