• Author: Georgescu Eugen-Robert
• Email: eugen.georgescu2202@stud.mec.upb.ro
• Master: AAC
• Academic year: 2023-2024
• Source files: snake.rar
• snake.pptx

The purpose of this project is to be able to play a snake game with a joystick. The game is displayed on the JDMO.96A-1 display and can be played using a joystick to set the direction in which the snake will move. If the snake eats himself a “GAME OVER” text will be displayed, otherwise, the snake grows after each food that it ate.

I used the following components for this project:

• WEMOS LOLIN32 based on the ESP32 microprocessor: a low-power system with integrated Wi-Fi and dual-mode Bluetooth;
• OLED 0.96” Screen: an OLED screen which has a reduced energy consumption, only 0.08W. The interface type is IIC;
• Black Biaxial Joystick module with 5 pins: a normal joystick

This function was used to start the display and clear it, and after that to initialize the snake and set its color to white.

void setup() {
  Serial.begin(115200);

  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;)
      ;
  }

  display.clearDisplay(); // Clear the display buffer

  // Initialize the snake
  for (int i = snakeSize - 1; i >= 0; i--) {
    snakeX[i] = snakeSize - 1 - i;
    snakeY[i] = 0;
  }

  // Set text color and size
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(1);

  // Start the game loop
  gameLoop();
}

Here I update the snake position then I draw it. After the snake is on the screen, I spawn a pixel random on the screen that can be eaten by the snake.

void gameLoop() {
  while (true) {
    // Update the snake position
    updateSnake();

    // Draw the snake
    drawSnake();

    // Check for joystick input
    checkJoystick();

    // Check if the snake eats the pixel
    if (snakeX[0] == pixelX && snakeY[0] == pixelY) {
      snakeSize++;
      spawnPixel(); // Spawn a new pixel after eating the current one
    }
    
    delay(200);
  }
}

On this function I update the entire snake positions (each of the pixels that make the body of the snake). Then I move the head on the direction of the pixel, I get this direction from a function called: checkJoystick. After that, I check if the snake hit the boundaries of the screen to teleport on the other side of the screen.

void updateSnake() {
    // Update the entire snake's position
  for (int i = snakeSize - 1; i > 0; i--) {
    snakeX[i] = snakeX[i - 1];
    snakeY[i] = snakeY[i - 1];
  }
  
  // Move the head of the snake based on the direction
  switch (direction) {
    case 0: // Right
      snakeX[0]++;
      break;
    case 1: // Down
      snakeY[0]++;
      break;
    case 2: // Left
      snakeX[0]--;
      break;
    case 3: // Up
      snakeY[0]--;
      break;
  }
  
  // Check for collisions with the screen boundaries
  if (snakeX[0] >= SCREEN_WIDTH / 8) {
    snakeX[0] = 0;
  } else if (snakeX[0] < 0) {
    snakeX[0] = SCREEN_WIDTH / 8 - 1;
  }

  if (snakeY[0] >= SCREEN_HEIGHT / 8) {
    snakeY[0] = 0;
  } else if (snakeY[0] < 0) {
    snakeY[0] = SCREEN_HEIGHT / 8 - 1;
  }
  for (int i = 0; i < snakeSize; i++) {
    Serial.println("Before collision (" + String(snakeX[i]) + "," + String(snakeY[i]) + ")");
  }
     // Check for collisions with the snake's body, excluding the head
  for (int i = 1; i < snakeSize; i++) {
    if (snakeX[0] == snakeX[i] && snakeY[0] == snakeY[i]) {
      // Snake head collided with its body, end the game
      endGame();
    }
  }
}

Used to draw the snake on the screen.

void drawSnake() {
  // Clear the display
  display.clearDisplay();

  // Draw the snake
  for (int i = 0; i < snakeSize; i++) {
    display.fillRect(snakeX[i] * 8, snakeY[i] * 8, 8, 8, SSD1306_WHITE);
  }

  // Draw the pixel
  display.fillRect(pixelX * 8, pixelY * 8, 8, 8, SSD1306_WHITE);

  // Display the buffer
  display.display();
}

I used this function to check the position of the joystick so I can give the snake the direction that I want it to move to. In this code I also made impossible for the snake to go in the opposite direction of the current one

void checkJoystick() {
  int xValue = analogRead(JOYSTICK_X);
  int yValue = analogRead(JOYSTICK_Y);
  int OK = 0;

  if (xValue < JOYSTICK_THRESHOLD && lastXValue <= JOYSTICK_THRESHOLD) {
    // Move right
    if (direction != 0 && direction != 2) {
      direction = 0;
      OK = 1;
    }
  } else if (xValue > JOYSTICK_THRESHOLD2 && lastXValue >= -JOYSTICK_THRESHOLD) {
    // Move left
    if (direction != 2 && direction != 0) {
      direction = 2;
      OK = 1;
    }
  }

  if (yValue < JOYSTICK_THRESHOLD && lastYValue <= JOYSTICK_THRESHOLD && OK == 0) {
    // Move up
    if (direction != 3 && direction != 1) {
      direction = 3;
    }
  } else if (yValue > JOYSTICK_THRESHOLD2 && lastYValue >= -JOYSTICK_THRESHOLD && OK == 0) {
    // Move down
    if (direction != 1 && direction != 3) {
      direction = 1;

    }
  }

  lastXValue = xValue;
  lastYValue = yValue;
}

I spawn the food of the snake as a pixel random on the screen.

void spawnPixel() {
  // Generate random coordinates for the pixel
  pixelX = random(SCREEN_WIDTH / 8);
  pixelY = random(SCREEN_HEIGHT / 8);

  // Ensure the pixel does not spawn on the snake
  for (int i = 0; i < snakeSize; i++) {
    while (pixelX == snakeX[i] && pixelY == snakeY[i]) {
      pixelX = random(SCREEN_WIDTH / 8);
      pixelY = random(SCREEN_HEIGHT / 8);
    }
  }

  // Draw the pixel on the display
  display.fillRect(pixelX * 8, pixelY * 8, 8, 8, SSD1306_WHITE);
  display.display();
}

Print on the screen the GAME OVER message if the snake hit himself.

void endGame() {
  // Add your game-over logic here
      display.clearDisplay();
      display.setCursor(8,8);
      display.print("GAME OVER!");
      display.display();
      delay(5000);  // Display "You Lose" for 5 seconds

  // Print snake coordinates for debugging
  Serial.println("Snake Coordinates:");
  for (int i = 0; i < snakeSize; i++) {
    Serial.println("(" + String(snakeX[i]) + "," + String(snakeY[i]) + ")");
  }

  while (true) {
    // Do nothing
  }
}

Here I declared the screen and the pins that I used. I also declared 2 THRESHOLDS because when the joystick was on the middle, I constantly get values between 1850 and 1900 and I don’t want that those values to influent the movement. On the end I declared snake characteristics.

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 32

// Define the I2C address for the display
#define OLED_ADDR 0x3C

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_ADDR);

#define JOYSTICK_X A5
#define JOYSTICK_Y A6
#define JOYSTICK_THRESHOLD 1800
#define JOYSTICK_THRESHOLD2 2000

int snakeSize = 3;
int snakeX[100], snakeY[100];
int direction = 0; // 0: right, 1: down, 2: left, 3: up

The library that I used are:

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

And mostly I used the for the LCD.

As a conclusion for the project, I realized a snake game that can be controlled using a joystick. The purpose of the game is to eat as many food as possible and to not touch the rest of the body.

https://www.optimusdigital.ro/ro/senzori-senzori-de-atingere/742-modul-joystick-ps2-biaxial-negru-cu-5-pini.html?search_query=joystick&results=42
https://cleste.ro/ecra-oled-0-96-inch.html
https://cleste.ro/placa-dezvoltare-nodemcu-wifi-bluetooth-esp32.html
https://randomnerdtutorials.com/esp32-pinout-reference-gpios/
https://esp32io.com/tutorials/esp32-joystick