Simple 2d Arcade Space Shooter

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Simple 2d Arcade Space Shooter

I have created a simple machine that recreates the function of a classic 2D arcade spaceshooter. The player turns a ship left and right with a joystick, fires a laser with a button that has a cooldown if fired for too long, and must hit one of two enemies that periodically become poised to attack.

Supplies

3 SG90 Mini Servo: https://www.tinytronics.nl/en/mechanics-and-actuators/motors/servomotors/sg90-mini-servo

4 Leds (any color)

4 220 Ohm Resistors

1 5V Laser emitter: https://www.tinytronics.nl/en/lighting/lasers/red-laser-5v-650nm-wire

2-3 PCB Plates: https://www.tinytronics.nl/en/tools-and-mounting/prototyping-supplies/experiment-pcbs/experiment-pcb-5cm*7cm-lanes-and-islands

1 Arduino Uno R3 (different model may work as well): https://www.tinytronics.nl/en/development-boards/microcontroller-boards/arduino-compatible/arduino-uno-r3

1 Joystick: https://www.tinytronics.nl/en/switches/manual-switches/joysticks/ps2-joystick

1 Tactile Button (4 pins): https://www.tinytronics.nl/en/switches/manual-switches/pcb-switches/tactile-push-button-switch-momentary-4pin-6*6*5mm

Alpha Wire (1 meter is enough, 2 meters if you wish to be sure): https://www.tinytronics.nl/en/cables-and-connectors/cables-and-adapters/prototyping-wires/loose-wires/alpha-wire-single-core-solid-%C3%B81.5mm-0.33mm2-red-1m

Casing (I used a woodcutter and wood for it, but you can use cardboard or any other material that is handy for you)

The Code

#include <Servo.h>

#include <Button.h>

Servo playerServo;

Servo enemyServo1;

Servo enemyServo2;

Button onOffButton(A3);

int laserPower; //Ammunition for the laser

int enemy1AttackTimer; //Enemy becomes active when it reaches 500 - 20*difficulty, and attacks when it reaches 0

int enemy2AttackTimer; //Enemy becomes active when it reaches 500 - 20*difficulty, and attacks when it reaches 0

int enemy1MoveTimer;

int enemy2MoveTimer;

bool shieldUp;

bool enemy1Primed;

bool enemy2Primed;

int difficultyTimer; //Increases difficulty when reached, starts at 3000 and decreases with difficulty

int difficulty; //Starts at 1, decreases the thresholds for enemies attacking and their cooldown for attacking again. Max of 5

bool turnedOn;

int enemySensor1;

int enemySensor2;

int joystickValue;

int laserButtonValue;

int playerSoundPin = 3;

int gameSoundPin = 5;

void setup()

{

Serial.begin(9600); //Required to print serial stuff

pinMode(A0, INPUT); //Joystick X-As

pinMode(A1, INPUT); //Enemy light sensor #1

pinMode(A2, INPUT); //Enemy light sensor #2

onOffButton.begin(); // ON/OFF Button

pinMode(2, INPUT); //Laser Button

pinMode(playerSoundPin, OUTPUT); //Buzzer (sound emitter, PLAYER) ~

pinMode(4, OUTPUT); //Laser Emitter

pinMode(gameSoundPin, OUTPUT); //Buzzer (sound emitter, ENEMIES/GAME) ~

pinMode(6, OUTPUT); //Led (Laser power) ~

pinMode(7, OUTPUT); //Led (Player shield)

playerServo.attach(9); //Player movement servo ~

enemyServo1.attach(10); //Enemy #1 movement servo ~

enemyServo2.attach(11); //Enemy #2 movement servo ~

pinMode(12, OUTPUT); //Led (enemy #1 target hit)

pinMode(13, OUTPUT); //Led (enemy #2 target hit)

//onOffButtonHeld = false;

turnedOn = true;

laserPower = 255;

shieldUp = true;

enemy1AttackTimer = 700;

enemy2AttackTimer = 825;

enemy1MoveTimer = 50;

enemy2MoveTimer = 70;

enemy1Primed = false;

enemy2Primed = false;

difficultyTimer = 3000;

difficulty = 1;

}

void loop()

{

enemySensor1 = analogRead(A1);

enemySensor2 = analogRead(A2);

joystickValue = analogRead(A0);

laserButtonValue = analogRead(2);

Serial.println(enemySensor2);

if (turnedOn)

{

adjustDifficulty();

updateEnemyStatus();

updateEnemyMovement();

laserEmitting();

if (shieldUp) digitalWrite(7,HIGH);

else digitalWrite(7,LOW);

int playerServoPos = map(joystickValue, 0, 1023, 0, 180);

playerServo.write(180 - playerServoPos);

delay(50);

}

void updateEnemyStatus()

{

//Check on enemies and their attack status

enemy1AttackTimer -= 1;

if (enemy1AttackTimer <= 0)

{

if (shieldUp)

{

shieldUp = false;

enemy1Primed = false;

enemy1AttackTimer = 1000 - (difficulty * 75) + random(-100,100);

}

else

{

gameOver();

enemy1Primed = false;

enemy1AttackTimer = 1000 - (difficulty * 75) + random(-100,100);

}

//Now enemy 2

enemy2AttackTimer -= 1;

if (enemy2AttackTimer <= 0)

{

if (shieldUp)

{

shieldUp = false;

enemy2Primed = false;

enemy2AttackTimer = 1000 - (difficulty * 75) + random(-100,100);

}

else

{

gameOver();

enemy2Primed = false;

enemy2AttackTimer = 1000 - (difficulty * 75) + random(-100,100);

}

//Checking the enemies sensors' input and their leds

if (enemySensor1 >= 1000 && enemy1AttackTimer <= (500 - (difficulty * 20)))

{

digitalWrite(12,LOW);

enemy1Primed = false;

enemy1AttackTimer = 1000 - (difficulty * 75) + random(-100,100);

}

else if (enemy1AttackTimer <= (500 - (difficulty * 20)))

{

digitalWrite(12,HIGH);

if (enemy1Primed == false)

{

enemy1Primed = true;

}

if (enemy1AttackTimer <= 200)

{

if (enemy1AttackTimer % 4 == 0) digitalWrite(12,LOW);

else digitalWrite(12,HIGH);

}

else digitalWrite(12,LOW);

//Now for enemy 2

if (enemySensor2 >= 1000 && enemy2AttackTimer <= (500 - (difficulty * 20))) //ADJUST THIS BASED ON AMBIENT LIGHT

{

digitalWrite(13,LOW);

enemy2Primed = false;

enemy2AttackTimer = 1000 - (difficulty * 75) + random(-100,100);

}

else if (enemy2AttackTimer <= (500 - (difficulty * 20)))

{

if (enemy2Primed == false)

{

enemy2Primed = true;

}

if (enemy2AttackTimer <= 200)

{

if (enemy2AttackTimer % 3 == 0) digitalWrite(13,LOW);

else digitalWrite(13,HIGH);

}

else digitalWrite(13,HIGH);

}

else digitalWrite(13,LOW);

}

void updateEnemyMovement()

{

enemy1MoveTimer -= 1;

if (enemy1MoveTimer <= 0)

{

enemyServo1.write((enemy1AttackTimer % 90) + 45);

enemy1MoveTimer = 30 + random(0,20);

}

enemy2MoveTimer -= 1;

if (enemy2MoveTimer <= 0)

{

enemyServo2.write(random(45,135));

enemy2MoveTimer = 100 + random(0,50);

}

void laserEmitting()

{

//Laser button input and laser emitter output

if (laserButtonValue > 900)

{

if (laserPower > 0)

{

digitalWrite(4, HIGH);

laserPower -= 9;

}

else digitalWrite(4, LOW);

}

else

{

digitalWrite(4, LOW);

if (laserPower < 255) laserPower += 7;

}

//Led that displays laser power

if (laserPower <= 0) analogWrite(11, 0);

else if (laserPower >= 255) analogWrite(6, 255);

else analogWrite(6, laserPower);

}

void adjustDifficulty()

{

//Adjust difficulty timers

difficultyTimer -= 1;

if (difficultyTimer <= 0)

{

if (difficulty < 5)

{

difficulty += 1;

}

difficultyTimer = 3000 - (200 * difficulty);

}

void gameOver()

{

turnedOn = false;

laserPower = 0;

digitalWrite(4, LOW);

digitalWrite(6,LOW);

digitalWrite(7,LOW);

digitalWrite(12,LOW);

digitalWrite(13,LOW);

playerServo.write(90);

enemyServo1.write(90);

enemyServo2.write(90);

}

Initial Prototype

I begun creating this concept by testing the separate aspects of it on their own on my breadboard. First I tested the player movement and shooting, shown on the first video clip. Then I added the enemy behavior, and I combined both of those features into one cardboard prototype (shown on the second clip). The mechanics for this prototype are as follows:

The game starts when you press the start button. You can turn the player ship within a 180 degree angle using the joystick, and fire by holding the fire button. The ammo led (the green one in my case) shows how much "ammo" you have left, which depletes while you fire the laser and recovers when you don't fire it. The shield led (the blue one in my case) is lit up while you have your shield still.

The two enemies will move in small angles randomly, and periodically the red led next to them will light up. This means the enemy is ready to attack. You have a short amount of time, shown by the led blinking faster and faster, to hit the enemy's light sensor with your laser, or it will attack you. If you are attacked, you lose your shield. If you didn't have your shield, you lose the game.

I ended up removing the start button since I had problems with getting it to work. I also tried using sound effects with a buzzer in this prototype (audible in the clip), but I removed this from the final version too to simplify the wiring and design.

Putting the Circuits Together

Included is a diagram of the circuits and how to put them together, minus the joystick and the laser emitter. Using the provided code, the joystick's X-as pin needs to be connected to pin A0, and the laser emitter needs to be connected to pin 4.

I highly recommend soldering, as using jumper cables will likely result in the coming loose given the scope of the wiring. Using separate PCB plates for the enemy servos and for other components helps keep the wiring more separate.

The Casing

I made the casing using a laser cutter, with a pattern I made on this site https://en.makercase.com/#/

The exact size of the box depends on how large you wish to make the game. I recommend at least 30cm of length to have enough space to fit all the wiring inside.

I assembled the box using a hot glue gun, and with some tape to reinforce it. I used both hot glue and tape to fix the wires to the walls of the casing, and keep the components in place. I made holes on the top to put the joystick and the fire button there for the player to control. I made holes on the playable side of the game too for the servos and leds.

I also 3d printed some simple shapes to cover the player and enemy servos, though this is a purely visual touch and is not required for functionality.

End Results

I painted the casing as a final touch, to look more colorful. I also added a flap on top to block the laser from going beyond the reaches of the game.

In my final version, I made a mistake while putting the circuits together creating a short-circuit, which caused some of the functions (namely, the enemies) to not work. As they functioned normally in the cardboard prototype, they should work with the provided code and circuits. This video shows how the player ship and laser do work.

The way the game works is as follows:

The game starts when the arduino is connected. You can turn the player ship within a 180 degree angle using the joystick, and fire by holding the button. The ammo led (the green one in my case) shows how much "ammo" you have left, which depletes while you fire the laser and recovers when you don't fire it. The shield led (the blue one in my case) is lit up while you have your shield still.