Meet the Joystick — Reading X and Y

By the end of this mission, you will be able to:

• Explain how a joystick module measures two directions at once

• Describe what the joystick's center (rest) value represents

• Wire a joystick module to the ESP32 correctly

• Read and display X and Y values in the Serial Monitor

Game controllers, drone remotes, and RC car transmitters all use one component to control two directions at once: the joystick. In this lesson, you'll wire one up and read exactly what it's telling your ESP32.

Robo says: “A joystick is really two sensors hiding inside one stick. Let's wire it up and see both directions at once.”

A joystick module is really just two potentiometers built into one stick — one measures how far you've pushed left or right (the X axis), and the other measures how far you've pushed up or down (the Y axis). It also usually has a built-in push button (SW), triggered by pressing straight down on the stick.

When you're not touching the joystick, it doesn't rest at 0 — it rests near the middle of its range, around 2048 on the ESP32's 0-4095 scale. This “center value” is important because it tells your code the stick isn't being pushed in any direction.

This lesson's circuit connects the joystick like this:

• VCC → 3.3V

• GND → GND

• VRX → GPIO 34

• VRY → GPIO 35

• SW → GPIO 4 (button)

Read X and Y values in the Serial Monitor.

int xPin = 34;
int yPin = 35;
void setup() {
Serial.begin(115200);
}
void loop() {
int xValue = analogRead(xPin);
int yValue = analogRead(yPin);
Serial.print("X: ");
Serial.print(xValue);
Serial.print(" Y: ");
Serial.println(yValue);
delay(200);
}

🔧 Try It Yourself

Leave the joystick untouched, then push it in each direction, recording the readings each time:

Example: Resting — X: 2043 Y: 2051

• Resting (untouched)

• Pushed fully left

• Pushed fully up

🤔 Discuss With a Partner or Write Your Answer

Why do you think the joystick's resting value is around 2048 instead of 0? What would change about your code if the resting value were 0 instead?

1. A joystick module is really ________ potentiometers built into one stick.

2. The X axis measures ________/right movement, while the Y axis measures up/down movement.

3. When left untouched, a joystick rests near its ________ value, not 0.

4. The joystick's built-in button is usually connected to a pin labeled ________.

Draw a line (or write the matching letter in the blank) to connect each word to its meaning.

• I can explain how a joystick module measures two directions at once

• I can describe what the joystick's center (rest) value represents

• I can wire a joystick module to the ESP32 correctly

• I can read and display X and Y values in the Serial Monitor

Question 1: How many potentiometers are inside a typical joystick module?

🔍 Reveal answer (drag-select the blank space): B

Question 2: What does the joystick's Y axis measure?

🔍 Reveal answer (drag-select the blank space): B

Question 3: Approximately what value does the joystick rest at on the ESP32's 0-4095 scale?

🔍 Reveal answer (drag-select the blank space): B

🏆 Level Up

Can you make your code print “Centered”, “Left”, “Right”, “Up”, or “Down” based on the X and Y readings, instead of just the raw numbers?

Name one real device that uses a joystick, and explain what it's used to control.

🤖 Robo Says

Your joystick is reading both directions at once! Next up: Lesson 2 — you'll use those readings to light up LEDs based on direction.