#include <TinyGPSPlus.h>
#include <SoftwareSerial.h>


//GPS stuff
const byte gps_RX = 7, gps_TX = 6;// TXPin must be a PWM pin
const uint32_t GPSBaud = 9600;
TinyGPSPlus gps;
SoftwareSerial NEO6M(gps_RX, gps_TX);

//Sensor Stuff
const float BETA = 3950; // should match the Beta Coefficient of the thermistor
const byte motionPin = 13;
const byte buzzPin = 12;

//button stuff
const byte button_Vin = 9; 
const byte button_Vout = 11;

//pressure resistor stuff
const byte pressurePin_Vin = 8; 


void setup() {
  Serial.begin(9600);// put your setup code here, to run once:
  
  NEO6M.begin(GPSBaud);

  //thermistor is connected to A0
  pinMode(motionPin, INPUT_PULLUP); //motion sensor
  pinMode(buzzPin, OUTPUT); //Buzzer


pinMode(button_Vin, OUTPUT);
pinMode(button_Vout, INPUT_PULLUP);


pinMode(pressurePin_Vin, OUTPUT);
//read pressure with pin A1;

}


void loop() {

 int analogValue = analogRead(A0); //thermistor uses analog pins
  float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  
  int motion = digitalRead(motionPin);
  int pressure = analogRead(A1);
  int buzzTime = 250; //buzzer rhythm
  static int trackingMode = 0; //remembers if someone was in the backseat

  static int trackingTime = 0;

if (digitalRead(button_Vout) == 0) {
  Serial.println("Button Test Successful");
tone(buzzPin,150,50);
delay(buzzTime);
tone(buzzPin,250,50);
}




  while (NEO6M.available() > 0)
    if (gps.encode(NEO6M.read()))
      displayInfo();

  if (millis() > 5000 && gps.charsProcessed() < 10)
  {
    Serial.println(F("No GPS detected: check wiring."));
    while(true);
  }


  //---------------------

  //pressure sensor 
  Serial.print(pressure); 
  Serial.print("   ");
  //motion sensor
  Serial.print(motion);
  Serial.print("   ");
  //thermistor
  Serial.print(celsius);
  Serial.print("   ");
  
  if (motion == 1 || pressure < 15){
    trackingMode = 1; //someone is in the backseat
    trackingTime = 10; //memory of someone in backseat
  }

if (trackingMode == 1) {
  Serial.print("Passenger?");
  Serial.print("   ");
}


//alert siren for heat stroke or hypothermia threat
if (trackingMode == 1 && (celsius >= 37.8 || celsius <= 0)) {
Serial.print("DANGER!");
  Serial.print("   ");
tone(buzzPin,150,50);
delay(buzzTime);
tone(buzzPin,250,50);
} else delay(buzzTime); //delay compensates for buzzer usage

Serial.println();


if (trackingMode == 1) trackingTime--; //passenger memory fades

if (trackingTime == 0) trackingMode = 0;

} 

//---------end of the main loop--------------


void displayInfo()
{
  Serial.print(F("Location: ")); 
  if (gps.location.isValid())
  {
    Serial.print(gps.location.lat(), 6);
    Serial.print(F(","));
    Serial.print(gps.location.lng(), 6);
  }
  else
  {
    Serial.print(F("INVALID"));
  }

  Serial.print(F("  Date "));
  if (gps.date.isValid())
  {
    Serial.print(gps.date.month());
    Serial.print(F("/"));
    Serial.print(gps.date.day());
    Serial.print(F("/"));
    Serial.print(gps.date.year());
  }
  else
  {
    Serial.print(F("INVALID"));
  }

  
  Serial.println();
}