arduino-football

//Pin for white gate laser
#define WHITE_LED_PIN 13
//Pin for blue gate laser
#define BLUE_LED_PIN 8
//Pin for white gate photoresistor
#define WHITE_LDR_PIN A0
//Pin for blue gate photoresistor
#define BLUE_LDR_PIN A1

//Commands to arduino:
// 1 - start game
const int START_COMMAND = 1;
// 2 - stop game
const int STOP_COMMAND = 2;

//Commands from arduino:
// 'GOAL:WHITE' - goal to white gate
// 'GOAL:BLUE' - goal to blue gate
const char GOAL_PREFIX[] = "GOAL:";
const char WHITE_TEAM_NAME[] = "WHITE";
const char BLUE_TEAM_NAME[] = "BLUE";
// 'LISTENING' - waiting for commands
const char LISTENING_MESSAGE[] = "LISTENING";
// 'START' - game is started
const char START_GAME_MESSAGE[] = "START";
// 'CALIBRATION' - sensors are in calibration
const char CALIBRATION_MESSAGE[] = "CALIBRATION";
// 'STOP' - game is stopped
const char STOP_GAME_MESSAGE[] = "STOP";

//Timeout after which game will be automatically stopped
//15 minutes - 900000 ms
const long INACTIVITY_TIMEOUT = 900000;

//Minumum deviation that is necessary to count a goal
//E.g if deviation is 1.1 it means that when value on photoresistor exceeds calibrated maximum at least on 10%, goal will be counted
const int MINIMUM_SENSOR_DEVIATION = 1.1;

//Time in milliseconds for photoresistors calibration
const long CALIBRATION_TIME = 1000;

//Delay in milliseconds after goals to avoid multiple counting of the same goal 
const long DELAY_AFTER_GOALS = 1000;

//Delay in milliseconds to avoid interference on LDR right after lasers are 'ON'
const long DELAY_BEFORE_CALIBRATION = 200;

//Maximum values on photoresistors after calibration.
int maxWhiteSensorValue = 0;
int maxBlueSensorValue = 0;

//Is game currently running
boolean running = false;
//Milliseconds from last activity (from game start or from last goal)
long lastActivityTime = 0;

void setup()
{
  Serial.begin(9600); 
  pinMode(WHITE_LED_PIN, OUTPUT);
  pinMode(BLUE_LED_PIN, OUTPUT);
  Serial.println(LISTENING_MESSAGE);
}

void loop()
{
  if (running)
  {
    if (millis() - lastActivityTime >= INACTIVITY_TIMEOUT)
    {
      //Stop the game because of inactivity
      stopTheGame();
    }
    else
    {
      checkFootballGate(WHITE_LDR_PIN, maxWhiteSensorValue, WHITE_TEAM_NAME);
      checkFootballGate(BLUE_LDR_PIN, maxBlueSensorValue, BLUE_TEAM_NAME); 
    }
  }
  else
  {
    //If game isn't running, check serial port for incoming commands
    int serialValue = Serial.parseInt();
    if (serialValue == START_COMMAND) 
    {
      startTheGame();
    }
  }
}


//Turn on lasers and calibrate the photoresistors
void startTheGame()
{
  digitalWrite(WHITE_LED_PIN, HIGH);
  digitalWrite(BLUE_LED_PIN, HIGH);
  //Delay to avoid interference on LDR right after lasers are 'ON'
  delay(DELAY_BEFORE_CALIBRATION);
  Serial.println(CALIBRATION_MESSAGE);  
  calibrateSensors();
  
  running = true;
  lastActivityTime = millis();
  Serial.println(START_GAME_MESSAGE);  
}

void stopTheGame()
{
  Serial.println(STOP_GAME_MESSAGE);
  digitalWrite(WHITE_LED_PIN, LOW);
  digitalWrite(BLUE_LED_PIN, LOW);
  running = false;
}

//Measuring of maximum values on photoresistors during calibrationTime period
void calibrateSensors()
{
  maxWhiteSensorValue = 0;
  maxBlueSensorValue = 0;
  long startMillis = millis();
  while (millis() - startMillis < CALIBRATION_TIME) 
  {
    int whiteSensorValue = analogRead(WHITE_LDR_PIN);
    int blueSensorValue = analogRead(BLUE_LDR_PIN);
    // record the maximum sensor value
    if (whiteSensorValue > maxWhiteSensorValue) 
    {
      maxWhiteSensorValue = whiteSensorValue;
    }
    if (blueSensorValue > maxBlueSensorValue) 
    {
      maxBlueSensorValue = blueSensorValue;
    }
  }
}

void checkFootballGate(int ldrPin, int maxSensorValue, const char *teamName)
{
  int sensorValue = analogRead(ldrPin);
  //If sensorValue is exceeds maxValue at least on configured minimum deviation (which means that light flow is interrupted)
  if (sensorValue >= (maxSensorValue * MINIMUM_SENSOR_DEVIATION)) 
  {      
      Serial.print(GOAL_PREFIX);
      Serial.println(teamName);
      lastActivityTime = millis();
      checkForStopCommand();
      delay(DELAY_AFTER_GOALS);
  }
}

//Check serial port for stop game command
void checkForStopCommand()
{
  int serialValue = Serial.parseInt();
  if (serialValue == STOP_COMMAND)
  {
    stopTheGame();
  }
}