#include "PID_v1.h"

// Konstanta
#define SENSOR_NTC A0
#define LED_RED 11
#define LED_GREEN 10
const double SET_POINT = 27; //Suhu Nominal & Setpoint
const double NTC_NOMINAL = 10800; //Nilai Termistor pada 27 derajat C
const double BETA_COEF = 3950; //Koefisien beta termistor NTC
 
// Variabel PID
double setpoint = 27; // Suhu target dalam derajat Celsius
double input, output;
double Kp = 2, Ki = 3, Kd = 1; // Proposional = 2, Integral = 5, Derivative = 1

PID pidcs(&input, &output, &setpoint, Kp, Ki, Kd,P_ON_E, DIRECT);

void setup() {
  Serial.begin(115200);
  Serial.println(__FILE__);

  //menetukan Outpul Limit PID
  pidcs.SetOutputLimits(0, 100);

  // Nyalakan PID
  pidcs.SetMode(AUTOMATIC);

  pinMode(LED_RED, OUTPUT);
  digitalWrite(LED_RED, LOW);

  pinMode(LED_GREEN, OUTPUT);
  digitalWrite(LED_GREEN, LOW);
}

// Print ke serial monitor
void report(void) {
  static uint32_t last = 0;
  const int interval = 1000; // interval proses pembacaan suhu (Sample Time) = 1000 ms = 1 s

  if (millis() - last > interval) {
    last += interval;

    Serial.print("SP:");
    Serial.print(setpoint);
    Serial.print(" Suhu:");
    Serial.print(input);
    Serial.print(" Output PID:");
    Serial.print(output);
    Serial.print(' ');
    Serial.println();
  }
}

void loop() {

  input = bacaSuhu();
  pidcs.Compute();

  // Kendalikan LED RGB berdasarkan output PID
  analogWrite(LED_RED, abs(output));
  analogWrite(LED_GREEN, 255 - abs(output)); 

  report();
}

double bacaSuhu() {
  //baca nilai analog sensor
  int adcValue = analogRead(SENSOR_NTC);
  //menghitung nilai resistansi NTC berdasarkan ADC (Analog to Digital Converter) dengan hukum Ohm
  double resistance = NTC_NOMINAL / ((1023.0 / adcValue) - 1.0);
  //menghitung suhu menggunakan rumus Steinhart-Hart (mengonversi resistansi ke suhu)
  double temperature = 1.0 / ((log(resistance / NTC_NOMINAL) / BETA_COEF) + (1.0 / (SET_POINT + 273.15)));
  //suhu di konversi dari kelvin ke celsius
  temperature -= 273.15;
  return temperature;
}