#include <PID_v2.h>

#define LED_Pin 3
#define ADC A0

double Setpoint ; // will be the desired value
double Input; // photo sensor
double Output ; //LED

//PID parameters
double Kp=10, Ki=5, Kd=1; 
 
//create PID instance 
PID myPID(&Input, &Output, &Setpoint, Kp, Ki, Kd, DIRECT);
 
const float GAMMA = 1.2;
const float RL10 = 20.0;

void setup() 
{
  Serial.begin(115200);
  Serial.println("LDR infinity test");

    //Hardcode the brigdness value
  Setpoint = 75;
  //Turn the PID on
  myPID.SetMode(AUTOMATIC);
  //Adjust PID values
  myPID.SetTunings(Kp, Ki, Kd);

}

void loop() 
{
    //Read the value from the light sensor. Analog input : 0 to 1024. We map is to a value from 0 to 255 as it's used for our PWM function.
  Input = map(analogRead(ADC), 0, 1024, 0, 255);  // photo senor is set on analog pin 5
  //PID calculation
  myPID.Compute();
  //Write the output as calculated by the PID function
  analogWrite(LED_Pin,Output); //LED is set to digital 3 this is a pwm pin. 
  //Send data by serial for plotting 
  
  Serial.print(Input);
  Serial.print(" ");
  Serial.print(Output);
  Serial.print(" ");  
  Serial.print(Setpoint);
  Serial.println(" ");  

  //delay(100); 

  // Convert the analog value into lux value:
  int analogValue = analogRead(A0);
  float voltage = float(analogValue) / 1024.0 * 5.0;
  float resistance = 2000.0 * voltage / (1.0 - voltage / 5.0);
  float lux = pow(RL10 * 1e3 * pow(10.0, GAMMA) / resistance, (1.0 / GAMMA));

 // if(isfinite(lux))
 // {
  //  Serial.print("The brightness is ");
 //   Serial.print(lux);
 //   Serial.println(" lx");
 // }
 // else
 // {
 //   Serial.println("Too bright to measure");
 // }
 //   Serial.print(voltage);
 //   Serial.println(" V.");
  delay(100);
}