#include <PID_v1.h>

#define PIN_INPUT A0

//Define Variables we'll be connecting to
double Setpoint, Input, Output;

//Define the aggressive and conservative Tuning Parameters
double aggKp=4, aggKi=0.2, aggKd=1;
double consKp=1, consKi=0.05, consKd=0.25;

//Specify the links and initial tuning parameters
PID myPID(&Input, &Output, &Setpoint, consKp, consKi, consKd, DIRECT);

void setup()
{
  //initialize the variables we're linked to
Serial.begin(9600); //Start a serial session
Input = analogRead(PIN_INPUT);
Setpoint = 336;

//turn the PID on
myPID.SetMode(AUTOMATIC);
}

void loop()
{
Input = analogRead(PIN_INPUT);

double gap = abs(Setpoint-Input); //distance away from setpoint
if (gap < 10)
{  //we're close to setpoint, use conservative tuning parameters
 myPID.SetTunings(consKp, consKi, consKd);
}
else
{
  //we're far from setpoint, use aggressive tuning parameters
  myPID.SetTunings(aggKp, aggKi, aggKd);
}

myPID.Compute();

Serial.print("Setpoint = ");
Serial.print(Setpoint);
Serial.print(" Input = ");
Serial.print(Input);
Serial.print(" Output = ");
Serial.print(Output);
Serial.print("n");
// analogWrite(PIN_OUTPUT, Output);
}