Arduino Project
Whac a Mole
Course Introduction
In this lesson, we’ll build a Whac-A-Mole game using LEDs, buttons, an LCD display, and a buzzer, where players hit lit targets to score points before time runs out.
Note
If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.
1.1 Install Arduino IDE(Important)
1.2 Introduction of Arduino IDE
Wiring
Common Connections:
I2C LCD 1602
SDA: Connect to A4 on the Arduino.
SCL: Connect to A5 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.
LEDS
Blue: Connect the LED anode to 7 on the Arduino, and the cathode to a 220Ω resistor, then to the negative power bus on the breadboard.
Green: Connect the LED anode to 9 on the Arduino, and the cathode to a 220Ω resistor, then to the negative power bus on the breadboard.
Yellow: Connect the LED anode to 5 on the Arduino , and the cathode to a 220Ω resistor, then to the negative power bus on the breadboard.
Red: Connect the LED anode to 11 on the Arduino, and the cathode to a 220Ω resistor, then to the negative power bus on the breadboard.
Passive Buzzer
＋: Connect to 3 on the Arduino.
－: Connect to breadboard’s negative power bus.
Buttons
Blue Button: Connect to the negative power bus on the breadboard, and the other end to 6 on the Arduino board.
Green Button: Connect to the negative power bus on the breadboard, and the other end to 8 on the Arduino board.
Yellow Button: Connect to the negative power bus on the breadboard, and the other end to 4 on the Arduino board.
Red Button: Connect to the negative power bus on the breadboard, and the other end to 10 on the Arduino board.
Writing the Code
Note
You can copy this code into the Arduino IDE.
To install the library, use the Arduino Library Manager and search for LiquidCrystal I2C and install it.
Don’t forget to select the board(Arduino UNO R4 Minima) and the correct port before clicking the Upload button.
#include
#include
#define BUZZER_PIN 3
#define NUM_HOLES 4
#define GAME_DURATION 30000 // 30 seconds
// Updated pin mapping
const int ledPins[NUM_HOLES] = {5, 7, 9, 11};
const int btnPins[NUM_HOLES] = {4, 6, 8, 10};
LiquidCrystal_I2C lcd(0x27, 16, 2);
bool gameRunning = false;
int score = 0;
int hits = 0;
unsigned long gameStartTime;
unsigned long lastMoleTime = 0;
unsigned long lastLcdUpdate = 0;
unsigned long moleInterval = 1000; // initial spawn interval
bool activeMoles[NUM_HOLES];
void setup() {
for (int i = 0; i < NUM_HOLES; i++) {
pinMode(ledPins[i], OUTPUT);
pinMode(btnPins[i], INPUT_PULLUP);
}
pinMode(BUZZER_PIN, OUTPUT);
lcd.init();
lcd.backlight();
showStartMessage();
}
void loop() {
if (!gameRunning) {
if (digitalRead(btnPins[0]) == LOW) { // long press to start
delay(500);
if (digitalRead(btnPins[0]) == LOW) startGame();
}
} else {
unsigned long now = millis();
unsigned long elapsed = now - gameStartTime;
// spawn moles
if (now - lastMoleTime > moleInterval) {
spawnMoles();
}
// check hits
checkHit();
// difficulty scaling
if (elapsed > 20000) moleInterval = 400;
else if (elapsed > 10000) moleInterval = 600;
// update LCD every 200ms
if (now - lastLcdUpdate > 200) {
updateGameLCD(elapsed);
lastLcdUpdate = now;
}
// game end
if (elapsed > GAME_DURATION) {
endGame();
}
}
}
void showStartMessage() {
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Hold Btn1");
lcd.setCursor(0, 1);
lcd.print("to start game");
}
void startGame() {
gameRunning = true;
score = 0;
hits = 0;
gameStartTime = millis();
moleInterval = 1000;
clearAllMoles();
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Game Started!");
delay(1000);
lcd.clear();
}
void updateGameLCD(unsigned long elapsed) {
int timeLeft = (GAME_DURATION - elapsed) / 1000;
lcd.setCursor(0, 0);
lcd.print("Score:");
lcd.print(score);
lcd.print(" ");
lcd.setCursor(0, 1);
lcd.print("Time:");
lcd.print(timeLeft);
lcd.print("s ");
}
void spawnMoles() {
clearAllMoles();
int numMoles = random(1, 3); // 1 or 2 moles
if (millis() - gameStartTime > 20000) numMoles = random(2, 4); // late game more moles
for (int i = 0; i < numMoles; i++) {
int hole;
do {
hole = random(NUM_HOLES);
} while (activeMoles[hole]);
activeMoles[hole] = true;
digitalWrite(ledPins[hole], HIGH);
}
lastMoleTime = millis();
}
void clearAllMoles() {
for (int i = 0; i < NUM_HOLES; i++) {
activeMoles[i] = false;
digitalWrite(ledPins[i], LOW);
}
}
void checkHit() {
for (int i = 0; i < NUM_HOLES; i++) {
if (digitalRead(btnPins[i]) == LOW) {
delay(20); // debounce
if (activeMoles[i]) {
score += 10;
hits++;
tone(BUZZER_PIN, 1500, 100);
activeMoles[i] = false;
digitalWrite(ledPins[i], LOW);
} else {
score -= 5;
tone(BUZZER_PIN, 500, 100);
}
delay(150);
}
}
}
void endGame() {
gameRunning = false;
clearAllMoles();
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Score:");
lcd.print(score);
lcd.setCursor(0, 1);
lcd.print("Hits:");
lcd.print(hits);
tone(BUZZER_PIN, 1000, 300);
delay(300);
tone(BUZZER_PIN, 1500, 300);
delay(300);
noTone(BUZZER_PIN);
delay(3000);
showStartMessage();
}