#include <PID_v2.h>

#define LDR_INPUT 2 //LDR to A0

#define LED_OUTPUT 5 //LED to D3


//Variables
double Setpoint, Input, Output;
//PID Parameters
double Kp = 2, Ki = 10, Kd = 1;

//Start PID Instance

PID myPID(&Input, &Output, &Setpoint, Kp, Ki, Kd, DIRECT);
void setup()

{
  //Start Serial
    Serial.begin(9600);
      //pinMode(LED_OUTPUT, OUTPUT);
        //Set point (brightness target)
          Input = analogRead(LDR_INPUT);
            Setpoint = 100;
              //Turn the PID on
                myPID.SetMode(AUTOMATIC);
                  //Adjust PID values
                    myPID.SetTunings(Kp, Ki, Kd);
                    }
                    void loop()
                    {
                      //Read photoresistor value

                        Input = map(analogRead(LDR_INPUT), 0, 1024, 0, 255);

                          //PID calculation

                            myPID.Compute();

                              //Write the output as calculated by the PID function

                                analogWrite(LED_OUTPUT, Output);


                                  //Send data for serial monitoring

                                    Serial.print(Input);

                                      Serial.print(" ");

                                        Serial.println(Output);

                                        }