/************************ TrafficLights3 **********************

Purpose: 
Emulates 2 sets of traffic lights at an intersection including green for go, 
yellow for clear intersection and red for stop. 
This is an example of a timing sequence (sequential program).

Additional information: 
Utilizes the LEDs on the Mobile Modular board
Red LEDs are at the top row (if not, have the instructor switch the cap colors)
Connections:
Light       Arduino pin     Terminal Block
NSgreen      pin 2            #46
NSyellow     pin 3            #42
NSred        pin 4            #38
EWgreen      pin 5            #49
EWyellow     pin 6            #45
EWred        pin 7            #41
NSwalk       pin 8
EWwalk       pin9
potInputPin  pin A0
             Ground           Ground
 
Created on July 7, 2020
 By Ron Ropson             
 */  
 
 const byte NSgreen=2; // naming the pins with familiar names makes programming easier
 const byte NSyellow=3;
 const byte NSred=4;
 const byte EWgreen=5; // we could use longer names like NorthSouthGreen55thStreet25 too!
 const byte EWyellow=6; // but it would be too much typing.
 const byte EWred=7;
 const byte EWwalkLight=8;
 const byte NSwalkLight=9;
 int potValue; 
 float potVoltage; 
 const byte potInputPin=0;



void setup() 
{  
   for(byte a=2;a<10;a++) // another cool programming tool to make pins 2-7 outputs all at once
   {
    pinMode(a,OUTPUT);
   }
  // Setup initial conditions
  digitalWrite(NSgreen,LOW);// When the lights are first on, we can't have them all lit
  digitalWrite(NSyellow,HIGH); // nor can we have them all off. we could start with red, though!
  digitalWrite(NSred,LOW);
  digitalWrite(EWgreen,LOW);
  digitalWrite(EWyellow,LOW);
  digitalWrite(EWred,HIGH);
  flashLights(5); // This is something new: a call to a function.
                     // the number 5 is passed onto the function so 
                     // it knows how many times to blink
} 

void loop()
{
  allRed();// function call to make sure both sets are red before starting
  northSouthSequence();// perform the NS sequence green, then yellow, then red
  allRed();
  eastWestSequence();// perform the EW sequence green, then yellow, then red
  {
    potValue=analogRead(potInputPin);
    potVoltage=5.0*potValue/1023.0;
  }
}   

/*
 * flashinglights(int)
 * This function flashes the NS yellow lights
 * and flashes the EW red lights
 */
  
void flashLights(int times) // this is the function flashinglights.
                               // It blinks the lights the specified number of times then returns
{ 
  for(int a = 0; a<times ; a++)
   {
    delay(500);
    digitalWrite(NSyellow,LOW);
    digitalWrite (EWred,LOW);
    delay(500);
    digitalWrite(NSyellow,HIGH);
   digitalWrite (EWred,HIGH);
  }
}

/*
 * allRed()
 * This function turns both the NS and EW lights red
 * It also makes sure all the others are off
 * It simplifies programming sequence and is safe
 * if the program freezes
 * It us used before any green light turns on
 * so there is no confusion
 */

void allRed()
{
  digitalWrite(NSgreen,LOW);
  digitalWrite(NSyellow,LOW);
  digitalWrite(NSred,HIGH);
  digitalWrite(EWgreen,LOW);
  digitalWrite(EWyellow,LOW);
  digitalWrite(EWred,HIGH);
  delay(250);//so it's not instant from red on one street to green on the other
}

// turn the NS light from green to yellow to red
void northSouthSequence()
  {
  digitalWrite(NSred,LOW);// turn off red first
  digitalWrite(NSgreen,HIGH);
  digitalWrite(NSwalkLight,HIGH);
  delay(2000 + 4*analogRead(0));
  digitalWrite(NSwalkLight,LOW);
  delay(2000);
  digitalWrite(NSgreen,LOW); //make sure it's turned off first!
  digitalWrite(NSyellow,HIGH); // switch to yellow
  delay(2000);//for two seconds
  digitalWrite(NSyellow,LOW);// important! even though it takes only a few microseconds to
  digitalWrite(NSred,HIGH);  // complete this task, the order is  vital, because if the 
  // microcontroller freezes up, we don't want confusing signals,
  }

 // turn the EW light from green to yellow to red 
void eastWestSequence()
  {
  digitalWrite(EWred,LOW);// turn off red first
  digitalWrite(EWgreen,HIGH);
  digitalWrite(EWwalkLight, HIGH);
  delay(2000);
  digitalWrite(EWwalkLight, LOW);
  delay(2000);
  digitalWrite(EWgreen,LOW); //make sure it's turned off first!
  digitalWrite(EWyellow,HIGH); // switch to yellow
  delay(2000);//for two seconds
  digitalWrite(EWyellow,LOW);// important! even though it takes only a few microseconds to
  digitalWrite(EWred,HIGH);  // complete this task, the order is  vital, because if the 
  // microcontroller freezes up, we don't want confusing signals,
  }