Joystick Status Display Using LCD

Last revision • 25/06/2025

HARDWARE REQUIRED:

PICUNO Microcontroller board
1 × 16x2 I2C LCD Display
1 × HW-504 Joystick Module
Jumper wires
USB cable
9V Battery with a snap connector (to power the board via the DC Jack)

DESCRIPTION:

This project creates a simple but powerful user interface by reading all the inputs from a Joystick XY module and displaying them in real-time. The program continuously reads the Analog values from the X and Y axes to get a 2D coordinate, as well as the digital state of the built-in push-button. This data is then formatted and sent to a 16x2 I2C LCD screen for immediate feedback. This project serves as a fundamental building block for any system that requires user control, such as games, navigation menus, or robot controllers.

CIRCUIT DIAGRAM:

Connect the LCD Module's GND pin to a GND pin on board.
Connect the LCD Module's VCC pin to the 5V pin on board.
Connect the LCD Module's SDA pin GPIO 4 (SDA Pin on PICUNO).
Connect the LCD Module's SCL pin GPIO 5 (SCL Pin on PICUNO).
JOYSTICK MODULE:

Connect the VCC pin to 5V pin on the board.
Connect the GND pin to GND pin on board.
Connect the VRx pin to Analog Pin A0 (GPIO 26).
Connect the VRy pin to Analog Pin A1 (GPIO 27).
Connect the SW (Switch) pin to GPIO 8.

SCHEMATIC:

LCD VCC → 5V

LCD GND → GND

LCD SDA → GPIO 4 (Board SDA Pin)

LCD SCL → GPIO 5 (Board SCL Pin)

Joystick Module:

VCC → 5V

GND → GND

VRx → A0

VRy → A1

SW → GPIO 8

CODE -- C:

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Pin Definitions
const int JOY_X_PIN = A0;
const int JOY_Y_PIN = A1;
const int JOY_SW_PIN = 8;

// LCD Setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  pinMode(JOY_SW_PIN, INPUT_PULLUP);

  lcd.init();
  lcd.backlight();
  lcd.print("Joystick Test");
  delay(1000);
}

void loop() {
  // Read the values from the joystick
  int xValue = analogRead(JOY_X_PIN);
  int yValue = analogRead(JOY_Y_PIN);
  int swValue = digitalRead(JOY_SW_PIN);

  // Clear the screen and display values
  lcd.clear();

  // Display X and Y values on the top line
  lcd.setCursor(0, 0);
  lcd.print("X:");
  lcd.print(xValue);

  lcd.setCursor(8, 0);
  lcd.print("Y:");
  lcd.print(yValue);

  // Display the button state on the bottom line
  lcd.setCursor(0, 1);
  lcd.print("Switch: ");
  if (swValue == LOW) { // LOW means pressed because of INPUT_PULLUP
    lcd.print("Pressed");
  } else {
    lcd.print("Off");
  }

  delay(200);
}

pinMode(JOY_SW_PIN, INPUT_PULLUP); - Configures the joystick's button pin as an input and enables an internal resistor to keep the signal stable.

analogRead(JOY_X_PIN) - Reads the joystick's position on one axis as a value from 0-1023.

digitalRead(JOY_SW_PIN) - Reads the state of the button. Because we are using INPUT_PULLUP, the value will be LOW when pressed.

lcd.setCursor(col, row) - This command is used to precisely position the text on the screen before printing.

CODE -- PYTHON:

from machine import Pin, ADC, I2C
from i2c_lcd import I2cLcd
from time import sleep

adc_x = ADC(Pin(26)) # A0
adc_y = ADC(Pin(27)) # A1

# Setup Digital pin for Joystick Switch
button = Pin(8, Pin.IN, Pin.PULL_UP)

i2c = I2C(0, scl=Pin(5), sda=Pin(4))
lcd = I2cLcd(i2c, 0x27, 2, 16)

lcd.putstr("Joystick Test")
sleep(1)
lcd.clear()

while True:
  # Read all the values
  x_val = adc_x.read_u16()
  y_val = adc_y.read_u16()
  sw_val = button.value()

  # Format the text for display
  x_text = f"X:{x_val:<5}" # Format X value
  y_text = f"Y:{y_val:<5}" # Format Y value
  sw_text = f"Switch: {'Pressed' if sw_val == 0 else 'Off'}"

  # Display on the LCD
  lcd.move_to(0, 0)
  lcd.putstr(f"{x_text} {y_text}")

  lcd.move_to(0, 1)
  lcd.putstr(f"{sw_text:<16}")

  sleep(0.2)

adc_x = ADC(Pin(26)) - Creates an Analog-to-Digital Converter object for the X-axis pin.

button = Pin(8, Pin.IN, Pin.PULL_UP) - Configures the button pin as an input with an internal pull-up resistor.

x_val = adc_x.read_u16() - Reads the joystick's X-axis position as a 16-bit value (0-65535).

sw_text = f"Switch: {'Pressed' if sw_val == 0 else 'Off'}" - This is a conditional expression (ternary operator) inside an f-string. It neatly formats the button status into the correct string in one line.

lcd.putstr(...) - Prints the final formatted strings to the LCD screen.