Control in Your Hands: ESP32 with 2-Axis Joystick

🔧 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:

⚠️ 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

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🛠️ Applications:

• Controlling robot car direction/speed

• Manual control of servo motors

• Gamepad for ESP32 projects

• Navigating on OLED displays

• Triggering actions (via push button)

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🚀 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);

}