LCD turning on but not displaying things

Other Hardware Displays
1

Is there a problem with this code? The LCD seems to turn on but nothing is displayed.

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

// I2C address for the LCD
#define LCD_ADDRESS 0x27 // Change this to your LCD's I2C address

// Constants
const int redLEDs[6] = {8, 9, 10, 11, 12, 13};
const int buttonPins[6] = {2, 3, 4, 5, 6, 7};
const int timeButton30 = A1; // Button to set game time to 30 seconds (using pin A6, not available on Uno, choose another)
const int timeButton60 = A2; // Button to set game time to 60 seconds (using pin A7, not available on Uno, choose another)

// Initialize the LCD with I2C address
LiquidCrystal_I2C lcd(LCD_ADDRESS, 16, 2); // Change 16x2 if your LCD is a different size

void setup() {
  // Initialize Wire library for I2C
  Wire.begin();

  // Initialize LED pins
  for (int i = 0; i < 6; i++) {
    pinMode(redLEDs[i], OUTPUT);
    digitalWrite(redLEDs[i], LOW);
  }

  // Initialize button pins
  for (int i = 0; i < 6; i++) {
    pinMode(buttonPins[i], INPUT_PULLUP);
  }

  // Initialize time control button pins
  pinMode(timeButton30, INPUT_PULLUP);
  pinMode(timeButton60, INPUT_PULLUP);

  // Initialize the LCD
  lcd.init();
  lcd.backlight(); // Turn on the backlight
  lcd.setCursor(0, 0);
  lcd.print("Select Time:");
  lcd.setCursor(0, 1);
  lcd.print("30s or 60s");

  // Wait for time selection
  unsigned long gameTime = 30000; // Default 30 seconds
  while (true) {
    if (digitalRead(timeButton30) == LOW) {
      gameTime = 30000;
      break;
    }
    if (digitalRead(timeButton60) == LOW) {
      gameTime = 60000;
      break;
    }
  }

  // Clear the LCD
  lcd.clear();

  // Display game time selection
  lcd.setCursor(0, 0);
  lcd.print("Time Selected:");
  lcd.setCursor(0, 1);
  lcd.print(gameTime / 1000);
  lcd.print(" seconds");

  // Wait for 2 seconds before starting
  delay(2000);

  // Initialize score
  int score = 0;

  // Initialize start time
  unsigned long startTime = millis();

  // Start game loop
  while (millis() - startTime < gameTime) {
    // Choose random LED
    int ledIndex = random(6);
    int ledPin = redLEDs[ledIndex];

    // Light up red LED
    digitalWrite(ledPin, HIGH);

    // Wait for button press
    int buttonPressed = -1;
    unsigned long buttonStartTime = millis();
    while (buttonPressed == -1 && millis() - buttonStartTime < 2000) {
      for (int i = 0; i < 6; i++) {
        if (digitalRead(buttonPins[i]) == LOW) {
          buttonPressed = i;
          break;
        }
      }
    }

    // Check if button was pressed
    if (buttonPressed == ledIndex) {
      // Add point to score
      score++;
    } else if (buttonPressed != -1) {
      // Deduct point for wrong button press
      score--;
    }

    // Turn off red LED
    digitalWrite(ledPin, LOW);

    // Update score on LCD
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Score:");
    lcd.print(score);
    lcd.setCursor(0, 1);
    lcd.print("Time:");
    lcd.print((gameTime - (millis() - startTime)) / 1000);
    lcd.print("s");
  }

  // Display final score
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Final Score:");
  lcd.setCursor(0, 1);
  lcd.print(score);

  // Wait for 10 seconds before resetting
  delay(10000);

  // Reset LED states
  for (int i = 0; i < 6; i++) {
    digitalWrite(redLEDs[i], LOW);
  }
}

void loop() {
  // No need for any code here as the game logic is handled in setup()
}
2

Did you run the i2c scanner example to see if the LCD screen shows up there as address 0x27?

Edit: Did you try the LCD Display example included with the LCD library?

3

check with an I2C Scanner Sketch (you will find it in the Wire examples) if your LCD Expander is responding to 0x27 or to another address.

4

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