NerdyTimer.h

class NerdyTimer
{
  //declare pins for solar panels that are part of laser trip wire 
  int startPin;
  int stopPin;  

  //values that determine if the laser has been tripped or not 
  int startPinThreshhold;
  int stopPinThreshhold;
  
  //race time trackers
  unsigned long raceStartTime;
  unsigned long raceElapsedTime;
  boolean timerRunStatus;
  
  //7-segment display variables
  byte matrix_addr;
  int displayBlinkRate;
  Adafruit_7segment matrix = Adafruit_7segment();

  public:
  NerdyTimer(int _startPin, int _stopPin, byte _matrix_addr)
  {
    startPin = _startPin;
    stopPin = _stopPin;
    matrix_addr = _matrix_addr;
       
    raceElapsedTime=0.0;
    
    displayBlinkRate=0;	
    timerRunStatus=false;  
   
    startPinThreshhold=0;
    stopPinThreshhold=0; 
  }
  
  void calibrateSolarPanels(){
    //assuming that the solar panels are "seeing" the laser when this routine takes place
    // calibrate with 10 samples
    int samples=0;
    while (samples < 10) { 
      startPinThreshhold+=analogRead(startPin);
      stopPinThreshhold+=analogRead(stopPin);
      samples++;
      delay(1);
    }
    startPinThreshhold=startPinThreshhold/samples;
    stopPinThreshhold=stopPinThreshhold/samples;
  }

  void start_display(){
    matrix.begin(matrix_addr);
  }
  
  void update_display(){
    matrix.blinkRate(displayBlinkRate);
    matrix.print(raceElapsedTime);
    matrix.writeDisplay();
    delay(1);
  }
  
  void update_time(){
  raceElapsedTime = (millis()-raceStartTime)/10.0;//convert to seconds
  }
  
  void check_start_pin_status(){ 
    int pinStatus = analogRead(startPin);
    Serial.print(startPinThreshhold);
    Serial.print(pinStatus);
    if(pinStatus < (startPinThreshhold*.90)){ //race start laser has been tripped
      raceStartTime = millis();
      timerRunStatus = true; //start race
      displayBlinkRate=0;
 
    }
  }
  
  
  void check_stop_pin_status(){
    int pinStatus = analogRead(stopPin);
    if(pinStatus < (stopPinThreshhold*.80)){ //race finish laser has been tripped
      timerRunStatus = false;
      displayBlinkRate = 2;
    }
  }
  
  void reset_status(){
    timerRunStatus = false;
    displayBlinkRate = 0;
    raceElapsedTime = 0.0; 
  }
  
  void update_race_status(){
    if (timerRunStatus == false){ //if race hasn't started, keep polling the start pin 
      check_start_pin_status();
    }
    else{ //race has started
      check_stop_pin_status(); 
      update_time();
    }
    
      update_display();
  }
};