#include <SoftwareSerial.h>

#define RX 2
#define TX 1

#define LED_OUT A3

SoftwareSerial CustomSerial(2,1);
const long A = 1000;     //Resistencia en oscuridad en KΩ
const int B = 27;        //Resistencia a la luz (10 Lux) en KΩ
const int Rc = 10;       //Resistencia calibracion en KΩ

int value;
int ilum;
bool overrideON = false;

void setup()
{
  CLKPR = (1<<CLKPCE);
  CLKPR = (0<<CLKPS3)|(0<<CLKPS2)|(0<<CLKPS1)|(0<<CLKPS0);
  pinMode(A2, INPUT);
  pinMode(LED_OUT, OUTPUT);
  digitalWrite(LED_OUT,LOW);
  CustomSerial.begin(9600);
}
void loop()
{
  value = analogRead(A2);
  CustomSerial.print(value);
  ilum = ((long)value*A*10)/((long)B*Rc*(1024-value));
  CustomSerial.print(" Light value ");
  CustomSerial.print(ilum);
  CustomSerial.println(" lux");

  if(value>1020){
    CustomSerial.println("Button pressed");
    overrideON = !overrideON;
  }
  
  if((ilum>100 && ilum<1000)|| overrideON){
    // Light needed, turn light ON
    digitalWrite(LED_OUT,HIGH);
  }
  else {
    //Too dark (night) or too bright (Direct sunshine)
    //light not needed, turn light OFF
    digitalWrite(LED_OUT,LOW);
  }

  delay(1000); // Wait for 250 millisecond(s)
}