DIYables Web Apps Web Joystick
Overview
The WebJoystick example creates a virtual joystick interface accessible from any web browser. Designed for Arduino Uno R4 WiFi and DIYables STEM V4 IoT educational platform with enhanced robotics capabilities, built-in motor control features, and seamless integration with robotics educational modules. Perfect for controlling robots, vehicles, or any system requiring 2D position input.
Features
- Virtual Joystick: Interactive joystick control via web interface
- Real-time Coordinates: X/Y values from -100 to +100 for precise control
- Touch & Mouse Support: Works on desktop, tablet, and mobile devices
- Configurable Auto-Return: Option for joystick to return to center when released
- Sensitivity Control: Adjustable sensitivity to prevent excessive updates
- Visual Feedback: Real-time position display and coordinate values
- WebSocket Communication: Instant response without page refresh
- Center Position: Clear center position indicator for neutral control
- Platform Extensible: Currently implemented for Arduino Uno R4 WiFi, but can be extended for other hardware platforms. See DIYables_WebApps_ESP32
Hardware Preparation
Or you can buy the following kits:
| 1 | × | DIYables STEM V4 IoT Starter Kit (Arduino included) | |
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
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 .
Setup Instructions
Detailed Instructions
Follow these instructions step by step:
- If this is your first time using the Arduino Uno R4 WiFi/DIYables STEM V4 IoT, refer to the tutorial on setting up the environment for Arduino Uno R4 WiFi/DIYables STEM V4 IoT in the Arduino IDE.
- Connect the Arduino Uno R4/DIYables STEM V4 IoT board to your computer using a USB cable.
- Launch the Arduino IDE on your computer.
- Select the appropriate Arduino Uno R4 board (e.g., Arduino Uno R4 WiFi) and COM port.
- Navigate to the Libraries icon on the left bar of the Arduino IDE.
- Search "DIYables WebApps", then find the DIYables 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 WebApps WebJoystick example, or copy the above code and paste it to the editor of Arduino IDE
/*
* DIYables WebApp Library - Web Joystick Example
*
* This example demonstrates the Web Joystick feature:
* - Interactive joystick control via web interface
* - Real-time X/Y coordinate values (-100 to +100)
* - Control pins based on joystick position
*
* Hardware: Arduino Uno R4 WiFi or DIYables STEM V4 IoT
*
* 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 http://[IP_ADDRESS]/webjoystick
*/
#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
// MEMORY SAFETY FIX: Use static factory to avoid stack object lifetime issues
static UnoR4ServerFactory serverFactory; // Static ensures lifetime matches program
DIYablesWebAppServer webAppsServer(serverFactory, 80, 81);
DIYablesHomePage homePage;
// Configure joystick with autoReturn=false and sensitivity=5 (minimum 5% change to trigger updates)
DIYablesWebJoystickPage webJoystickPage(false, 5);
// Variables to store current joystick values
int currentJoystickX = 0;
int currentJoystickY = 0;
void setup() {
Serial.begin(9600);
delay(1000);
// TODO: initialize your hardware pins here
Serial.println("DIYables WebApp - Web Joystick Example");
// Add home and web joystick pages
webAppsServer.addApp(&homePage);
webAppsServer.addApp(&webJoystickPage);
// Optional: Add 404 page for better user experience
webAppsServer.setNotFoundPage(DIYablesNotFoundPage());
// Start the WebApp server
if (!webAppsServer.begin(WIFI_SSID, WIFI_PASSWORD)) {
while (1) {
Serial.println("Failed to start WebApp server!");
delay(1000);
}
}
// Set up joystick callback for position changes
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Store the received values
currentJoystickX = x;
currentJoystickY = y;
// Print joystick position values (-100 to +100)
Serial.println("Joystick - X: " + String(x) + ", 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));
// - Send commands to other devices via Serial, I2C, SPI, etc.
});
// Optional: Handle requests for current joystick values (when web page loads)
webJoystickPage.onJoystickValueToWeb([]() {
// Send the stored joystick values back to the web client
webJoystickPage.sendToWebJoystick(currentJoystickX, currentJoystickY);
Serial.println("Web client requested values - Sent to Web: X=" + String(currentJoystickX) + ", Y=" + String(currentJoystickY));
});
// You can change configuration at runtime:
// webJoystickPage.setAutoReturn(false); // Disable auto-return
// webJoystickPage.setSensitivity(10.0); // Only send updates when joystick moves >10% (less sensitive)
}
void loop() {
// Handle WebApp server communications
webAppsServer.loop();
// 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 Arduino UNO R4/DIYables STEM V4 IoT
- Open the Serial Monitor
- Check out the result on Serial Monitor. It looks like the below
COM6
DIYables WebApp - Web Joystick Example
INFO: Added app /
INFO: Added app /web-joystick
DIYables WebApp Library
Platform: Arduino Uno R4 WiFi
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 Joystick: http://192.168.0.2/web-joystick
==========================================
Autoscroll
Clear output
9600 baud
Newline
- If you do not see anything, reboot Arduino 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 like below image:
- Click to the Web Joystick link, you will see the Web Joystick app's UI like the below:
- Or you can also access the page directly by IP address followed by /web-joystick. For example: http://192.168.0.2/web-joystick
- Try controlling the virtual joystick by clicking and dragging on the joystick area and observe the X/Y coordinate values (-100 to +100) in the Serial Monitor.
Creative Customization - Adapt the Code to Your Project
2. Configure Joystick Settings
The joystick can be configured with different parameters:
Basic Configuration
// Create joystick with default settings (autoReturn=true, sensitivity=1)
DIYablesWebJoystickPage webJoystickPage;
Advanced 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);
How to Use the Joystick
Web Interface Controls
The joystick interface provides:
- Joystick Pad: Circular control area for touch/mouse input
- Position Indicator: Shows current joystick position
- Coordinate Display: Real-time X/Y values (-100 to +100)
- Center Point: Visual reference for neutral position
Operating the Joystick
Desktop (Mouse Control)
- Click and Drag: Click on joystick and drag to move
- Release: Joystick returns to center (if autoReturn=true)
- Click Position: Direct click to set joystick position
Mobile/Tablet (Touch Control)
- Touch and Drag: Touch joystick and drag finger to move
- Multi-touch: Single finger for precise control
- Release: Automatic return to center (if enabled)
Coordinate System
The joystick provides coordinates in a standard Cartesian system:
- X-axis: -100 (full left) to +100 (full right)
- Y-axis: -100 (full down) to +100 (full up)
- Center: X=0, Y=0 (neutral position)
- Corners: Diagonal positions provide combined X/Y values
Programming Examples
Basic Joystick Handler
void setup() {
// Set up joystick callback for position changes
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Store the received values
currentJoystickX = x;
currentJoystickY = y;
// Print joystick position values
Serial.println("Joystick - X: " + String(x) + ", Y: " + String(y));
// Add your control logic here
});
}
Motor Control Example
// Pin definitions for motor driver
const int MOTOR_LEFT_PIN1 = 2;
const int MOTOR_LEFT_PIN2 = 3;
const int MOTOR_RIGHT_PIN1 = 4;
const int MOTOR_RIGHT_PIN2 = 5;
const int MOTOR_LEFT_PWM = 9;
const int MOTOR_RIGHT_PWM = 10;
void setup() {
// Configure motor pins
pinMode(MOTOR_LEFT_PIN1, OUTPUT);
pinMode(MOTOR_LEFT_PIN2, OUTPUT);
pinMode(MOTOR_RIGHT_PIN1, OUTPUT);
pinMode(MOTOR_RIGHT_PIN2, OUTPUT);
pinMode(MOTOR_LEFT_PWM, OUTPUT);
pinMode(MOTOR_RIGHT_PWM, OUTPUT);
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
controlRobot(x, y);
});
}
void controlRobot(int x, int y) {
// Convert joystick coordinates to motor speeds
int leftSpeed = y + x; // Forward/backward + turn left/right
int rightSpeed = y - x; // Forward/backward - turn left/right
// Constrain speeds to valid range
leftSpeed = constrain(leftSpeed, -100, 100);
rightSpeed = constrain(rightSpeed, -100, 100);
// Control left motor
if (leftSpeed > 0) {
digitalWrite(MOTOR_LEFT_PIN1, HIGH);
digitalWrite(MOTOR_LEFT_PIN2, LOW);
analogWrite(MOTOR_LEFT_PWM, map(leftSpeed, 0, 100, 0, 255));
} else if (leftSpeed < 0) {
digitalWrite(MOTOR_LEFT_PIN1, LOW);
digitalWrite(MOTOR_LEFT_PIN2, HIGH);
analogWrite(MOTOR_LEFT_PWM, map(-leftSpeed, 0, 100, 0, 255));
} else {
digitalWrite(MOTOR_LEFT_PIN1, LOW);
digitalWrite(MOTOR_LEFT_PIN2, LOW);
analogWrite(MOTOR_LEFT_PWM, 0);
}
// Control right motor
if (rightSpeed > 0) {
digitalWrite(MOTOR_RIGHT_PIN1, HIGH);
digitalWrite(MOTOR_RIGHT_PIN2, LOW);
analogWrite(MOTOR_RIGHT_PWM, map(rightSpeed, 0, 100, 0, 255));
} else if (rightSpeed < 0) {
digitalWrite(MOTOR_RIGHT_PIN1, LOW);
digitalWrite(MOTOR_RIGHT_PIN2, HIGH);
analogWrite(MOTOR_RIGHT_PWM, map(-rightSpeed, 0, 100, 0, 255));
} else {
digitalWrite(MOTOR_RIGHT_PIN1, LOW);
digitalWrite(MOTOR_RIGHT_PIN2, LOW);
analogWrite(MOTOR_RIGHT_PWM, 0);
}
}
Servo Control Example
#include <Servo.h>
Servo panServo; // X-axis control (left/right)
Servo tiltServo; // Y-axis control (up/down)
void setup() {
// Attach servos to pins
panServo.attach(9);
tiltServo.attach(10);
// Center servos initially
panServo.write(90);
tiltServo.write(90);
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
controlServos(x, y);
});
}
void controlServos(int x, int y) {
// Map joystick coordinates to servo angles
int panAngle = map(x, -100, 100, 0, 180); // X controls pan (0-180°)
int tiltAngle = map(y, -100, 100, 180, 0); // Y controls tilt (inverted)
// Move servos to calculated positions
panServo.write(panAngle);
tiltServo.write(tiltAngle);
Serial.println("Pan: " + String(panAngle) + "°, Tilt: " + String(tiltAngle) + "°");
}
LED Position Indicator
// LED pins for position indication
const int LED_UP = 2;
const int LED_DOWN = 3;
const int LED_LEFT = 4;
const int LED_RIGHT = 5;
const int LED_CENTER = 13;
void setup() {
// Configure LED pins
pinMode(LED_UP, OUTPUT);
pinMode(LED_DOWN, OUTPUT);
pinMode(LED_LEFT, OUTPUT);
pinMode(LED_RIGHT, OUTPUT);
pinMode(LED_CENTER, OUTPUT);
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
updateLEDIndicators(x, y);
});
}
void updateLEDIndicators(int x, int y) {
// Turn off all LEDs first
digitalWrite(LED_UP, LOW);
digitalWrite(LED_DOWN, LOW);
digitalWrite(LED_LEFT, LOW);
digitalWrite(LED_RIGHT, LOW);
digitalWrite(LED_CENTER, LOW);
// Check if joystick is near center
if (abs(x) < 10 && abs(y) < 10) {
digitalWrite(LED_CENTER, HIGH);
return;
}
// Activate LEDs based on direction
if (y > 20) digitalWrite(LED_UP, HIGH);
if (y < -20) digitalWrite(LED_DOWN, HIGH);
if (x > 20) digitalWrite(LED_RIGHT, HIGH);
if (x < -20) digitalWrite(LED_LEFT, HIGH);
}
Advanced Configuration
Runtime Configuration Changes
void setup() {
// Initial setup with default values
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
handleJoystickInput(x, y);
});
// Change settings at runtime
webJoystickPage.setAutoReturn(false); // Disable auto-return
webJoystickPage.setSensitivity(10.0); // Reduce sensitivity
}
void handleJoystickInput(int x, int y) {
// Handle different modes based on current settings
static bool precisionMode = false;
// Toggle precision mode with extreme positions
if (abs(x) > 95 && abs(y) > 95) {
precisionMode = !precisionMode;
if (precisionMode) {
webJoystickPage.setSensitivity(1.0); // High sensitivity
Serial.println("Precision mode ON");
} else {
webJoystickPage.setSensitivity(10.0); // Low sensitivity
Serial.println("Precision mode OFF");
}
}
}
Dead Zone Implementation
void processJoystickWithDeadZone(int x, int y) {
const int DEAD_ZONE = 15; // 15% dead zone around center
// Apply dead zone filtering
int filteredX = (abs(x) < DEAD_ZONE) ? 0 : x;
int filteredY = (abs(y) < DEAD_ZONE) ? 0 : y;
// Scale values outside dead zone
if (filteredX != 0) {
filteredX = map(abs(filteredX), DEAD_ZONE, 100, 0, 100);
filteredX = (x < 0) ? -filteredX : filteredX;
}
if (filteredY != 0) {
filteredY = map(abs(filteredY), DEAD_ZONE, 100, 0, 100);
filteredY = (y < 0) ? -filteredY : filteredY;
}
// Use filtered values for control
controlDevice(filteredX, filteredY);
}
Speed Ramping
class SpeedController {
private:
int targetX = 0, targetY = 0;
int currentX = 0, currentY = 0;
unsigned long lastUpdate = 0;
const int RAMP_RATE = 5; // Change per update cycle
public:
void setTarget(int x, int y) {
targetX = x;
targetY = y;
}
void update() {
if (millis() - lastUpdate > 20) { // Update every 20ms
// Ramp X value
if (currentX < targetX) {
currentX = min(currentX + RAMP_RATE, targetX);
} else if (currentX > targetX) {
currentX = max(currentX - RAMP_RATE, targetX);
}
// Ramp Y value
if (currentY < targetY) {
currentY = min(currentY + RAMP_RATE, targetY);
} else if (currentY > targetY) {
currentY = max(currentY - RAMP_RATE, targetY);
}
// Apply ramped values
applyControlValues(currentX, currentY);
lastUpdate = millis();
}
}
void applyControlValues(int x, int y) {
// Your control logic here with smooth ramped values
Serial.println("Ramped - X: " + String(x) + ", Y: " + String(y));
}
};
SpeedController speedController;
void setup() {
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
speedController.setTarget(x, y);
});
}
void loop() {
server.loop();
speedController.update(); // Apply speed ramping
}
Hardware Integration Examples
Robot Car Control
void setupRobotCar() {
// Motor driver pins
pinMode(2, OUTPUT); // Left motor direction 1
pinMode(3, OUTPUT); // Left motor direction 2
pinMode(4, OUTPUT); // Right motor direction 1
pinMode(5, OUTPUT); // Right motor direction 2
pinMode(9, OUTPUT); // Left motor PWM
pinMode(10, OUTPUT); // Right motor PWM
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Tank drive calculation
int leftMotor = y + (x / 2); // Forward/back + steering
int rightMotor = y - (x / 2); // Forward/back - steering
// Constrain to valid range
leftMotor = constrain(leftMotor, -100, 100);
rightMotor = constrain(rightMotor, -100, 100);
// Control motors
setMotorSpeed(9, 2, 3, leftMotor); // Left motor
setMotorSpeed(10, 4, 5, rightMotor); // Right motor
});
}
void setMotorSpeed(int pwmPin, int dir1Pin, int dir2Pin, int speed) {
if (speed > 0) {
digitalWrite(dir1Pin, HIGH);
digitalWrite(dir2Pin, LOW);
analogWrite(pwmPin, map(speed, 0, 100, 0, 255));
} else if (speed < 0) {
digitalWrite(dir1Pin, LOW);
digitalWrite(dir2Pin, HIGH);
analogWrite(pwmPin, map(-speed, 0, 100, 0, 255));
} else {
digitalWrite(dir1Pin, LOW);
digitalWrite(dir2Pin, LOW);
analogWrite(pwmPin, 0);
}
}
Camera Gimbal Control
#include <Servo.h>
Servo panServo, tiltServo;
int panOffset = 90, tiltOffset = 90; // Center positions
void setupCameraGimbal() {
panServo.attach(9);
tiltServo.attach(10);
// Set initial center positions
panServo.write(panOffset);
tiltServo.write(tiltOffset);
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Calculate servo positions with offset
int panPos = panOffset + map(x, -100, 100, -45, 45); // ±45° range
int tiltPos = tiltOffset + map(y, -100, 100, -30, 30); // ±30° range
// Constrain to servo limits
panPos = constrain(panPos, 0, 180);
tiltPos = constrain(tiltPos, 0, 180);
// Move servos smoothly
panServo.write(panPos);
tiltServo.write(tiltPos);
});
}
RGB LED Color Control
const int RED_PIN = 9;
const int GREEN_PIN = 10;
const int BLUE_PIN = 11;
void setupRGBControl() {
pinMode(RED_PIN, OUTPUT);
pinMode(GREEN_PIN, OUTPUT);
pinMode(BLUE_PIN, OUTPUT);
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Convert joystick position to RGB values
int red = map(abs(x), 0, 100, 0, 255);
int green = map(abs(y), 0, 100, 0, 255);
int blue = map(abs(x + y), 0, 141, 0, 255); // Diagonal distance
// Apply quadrant-specific color mixing
if (x > 0 && y > 0) {
// Upper right: Red + Green = Yellow
blue = 0;
} else if (x < 0 && y > 0) {
// Upper left: Green + Blue = Cyan
red = 0;
} else if (x < 0 && y < 0) {
// Lower left: Blue + Red = Magenta
green = 0;
} else if (x > 0 && y < 0) {
// Lower right: Red only
green = blue = 0;
}
// Set RGB values
analogWrite(RED_PIN, red);
analogWrite(GREEN_PIN, green);
analogWrite(BLUE_PIN, blue);
});
}
Troubleshooting
Common Issues
1. Joystick not responding
- Check WebSocket connection status in browser console
- Verify network connectivity
- Refresh browser page
- Check Serial Monitor for errors
2. Jerky or inconsistent movement
- Increase sensitivity value to reduce update frequency
- Implement dead zone filtering
- Add speed ramping for smooth transitions
- Check for network latency issues
3. Auto-return not working
- Verify autoReturn setting: webJoystickPage.setAutoReturn(true)
- Check browser compatibility (some touch devices vary)
- Test with different input methods (mouse vs touch)
4. Values not reaching full range
- Check joystick calibration in web interface
- Verify coordinate calculations in callback
- Test with different browser/device combinations
Debug Tips
Add comprehensive debugging:
void debugJoystickState(int x, int y) {
Serial.println("=== Joystick Debug ===");
Serial.println("X: " + String(x) + " (" + String(map(x, -100, 100, 0, 100)) + "%)");
Serial.println("Y: " + String(y) + " (" + String(map(y, -100, 100, 0, 100)) + "%)");
Serial.println("Distance from center: " + String(sqrt(x*x + y*y)));
Serial.println("Angle: " + String(atan2(y, x) * 180 / PI) + "°");
Serial.println("=====================");
}
Project Ideas
Robotics Projects
- Remote-controlled robot car
- Robotic arm control
- Drone flight control (basic movements)
- Pet robot navigation
Home Automation
- Smart curtain control (open/close/position)
- Camera pan/tilt control
- Light brightness and color control
- Fan speed and direction control
Educational Projects
- Coordinate system teaching tool
- Motor control demonstrations
- Servo positioning experiments
- Gaming controller interfaces
Art and Creative Projects
- LED matrix pattern control
- Music visualization control
- Drawing robot control
- Interactive art installations
Integration with Other Examples
Combine with WebSlider
Use joystick for direction and sliders for speed/intensity:
// Use joystick for direction, sliders for speed limits
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
int maxSpeed = getSliderValue(); // From WebSlider
int scaledX = map(x, -100, 100, -maxSpeed, maxSpeed);
int scaledY = map(y, -100, 100, -maxSpeed, maxSpeed);
controlRobot(scaledX, scaledY);
});
Combine with WebDigitalPins
Use joystick positions to trigger digital pin states:
webJoystickPage.onJoystickValueFromWeb([](int x, int y) {
// Activate pins based on joystick quadrants
webDigitalPinsPage.setPinState(2, x > 50); // Right quadrant
webDigitalPinsPage.setPinState(3, x < -50); // Left quadrant
webDigitalPinsPage.setPinState(4, y > 50); // Upper quadrant
webDigitalPinsPage.setPinState(5, y < -50); // Lower quadrant
});
Next Steps
After mastering the WebJoystick example, try:
- WebSlider - For additional analog control
- WebDigitalPins - For discrete on/off control
- WebMonitor - For debugging joystick values
- MultipleWebApps - Combining joystick with other controls
Support
For additional help:
- Check the API Reference documentation
- Visit DIYables tutorials: https://newbiely.com/tutorials/arduino-uno-r4/arduino-uno-r4-diyables-webapps
- Arduino community forums