Control in Your Hands: ESP32 with 2-Axis Joystick

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🔧 What is an Analog Joystick?

An analog joystick typically has:

2 potentiometers (one for X-axis, one for Y-axis)
1 push button (built-in, press down on the joystick)

📤 Joystick Outputs:

X-axis → Analog voltage (0V to Vcc) depending on horizontal tilt.
Y-axis → Analog voltage depending on vertical tilt.
SW (Switch) → Digital LOW when pressed, HIGH when idle (pull-up resistor inside).

🧰 Components Required:

ESP32 (DevKit v1 or any compatible board)
Analog Joystick Module (usually with 5 pins)
Jumper wires
Breadboard (optional)
USB cable to program ESP32

⚙️ Pinout of Joystick:

Joystick Pin	Function	Connect to ESP32
GND	Ground	GND
+5V / VCC	Power Supply	3.3V or 5V
VRx	X-axis analog	GPIO 34 (or any ADC pin)
VRy	Y-axis analog	GPIO 35 (or any ADC pin)
SW	Button	GPIO 25 (or any digital input)

⚠️ Use ADC-only pins for analog (e.g., GPIO34–GPIO39). These are input-only.

🎯 What Do the Values Mean?
Analog range: 0 to 4095 (ESP32 is 12-bit ADC)

Center position: ~2048

Tilt Left/Down: Closer to 0

Tilt Right/Up: Closer to 4095

Button: Reads LOW (0) when pressed, HIGH (1) when idle

🛠️ Applications:
Controlling robot car direction/speed

Manual control of servo motors

Gamepad for ESP32 projects

Navigating on OLED displays

Triggering actions (via push button)

🚀 Bonus: Using map() Function
You can convert X/Y readings into -100 to +100 range like this:

 
int xMapped = map(xValue, 0, 4095, -100, 100);
int yMapped = map(yValue, 0, 4095, -100, 100);
Useful for:

Speed control

Servo angles

UI navigation

   HOW TO OPERATE

 

const int xPin = 12;         // VRx
const int yPin = 13;         // VRy
const int buttonPin = 14;    // SW (built-in joystick button)

void setup() {
  Serial.begin(115200);
  pinMode(buttonPin, INPUT_PULLUP); // Use internal pull-up resistor for button
}

void loop() {
  int xValue = analogRead(xPin);
  int yValue = analogRead(yPin);
  bool buttonPressed = digitalRead(buttonPin) == LOW; // Pressed = LOW

  // Convert analog values to voltage (ESP32 has 12-bit ADC = 4095 max)
  float xVolt = (xValue * 3.3) / 4095.0;
  float yVolt = (yValue * 3.3) / 4095.0;

  // Print joystick values
  Serial.print("X: ");
  Serial.print(xVolt, 2);
  Serial.print(" V\tY: ");
  Serial.print(yVolt, 2);
  Serial.print(" V\tButton: ");
  Serial.println(buttonPressed ? "Pressed" : "Released");

  delay(200);
}

⚠️ Use ADC-only pins for analog (e.g., GPIO34–GPIO39). These are input-only.

🎯 What Do the Values Mean?
Analog range: 0 to 4095 (ESP32 is 12-bit ADC)

Center position: ~2048

Tilt Left/Down: Closer to 0

Tilt Right/Up: Closer to 4095

Button: Reads LOW (0) when pressed, HIGH (1) when idle

🛠️ Applications:
Controlling robot car direction/speed

Manual control of servo motors

Gamepad for ESP32 projects

Navigating on OLED displays

Triggering actions (via push button)

🚀 Bonus: Using map() Function
You can convert X/Y readings into -100 to +100 range like this:

 
int xMapped = map(xValue, 0, 4095, -100, 100);
int yMapped = map(yValue, 0, 4095, -100, 100);
Useful for:

Speed control

Servo angles

UI navigation

   HOW TO OPERATE

 

const int xPin = 12;         // VRx
const int yPin = 13;         // VRy
const int buttonPin = 14;    // SW (built-in joystick button)

void setup() {
  Serial.begin(115200);
  pinMode(buttonPin, INPUT_PULLUP); // Use internal pull-up resistor for button
}

void loop() {
  int xValue = analogRead(xPin);
  int yValue = analogRead(yPin);
  bool buttonPressed = digitalRead(buttonPin) == LOW; // Pressed = LOW

  // Convert analog values to voltage (ESP32 has 12-bit ADC = 4095 max)
  float xVolt = (xValue * 3.3) / 4095.0;
  float yVolt = (yValue * 3.3) / 4095.0;

  // Print joystick values
  Serial.print("X: ");
  Serial.print(xVolt, 2);
  Serial.print(" V\tY: ");
  Serial.print(yVolt, 2);
  Serial.print(" V\tButton: ");
  Serial.println(buttonPressed ? "Pressed" : "Released");

  delay(200);
}