#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#include <PID_v1.h>

// Define the pins for the temperature sensor
const int tempSensorPin = A0;

// Define the OLED display object
Adafruit_SSD1306 display(128, 64, &Wire, -1);

// Define PID parameters
double Setpoint = 25.0;  // Setpoint temperature in degrees Celsius
double Input, Output;
double Kp = 2.0;         // Proportional term
double Ki = 5.0;         // Integral term
double Kd = 1.0;         // Derivative term

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

void setup() {
  // Initialize the OLED display
  display.begin(SSD1306_I2C_ADDRESS, &Wire);
  display.display();
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);

  // Initialize the PID controller
  myPID.SetMode(AUTOMATIC);
  myPID.SetSampleTime(1000);  // 1 second sample time
  myPID.SetOutputLimits(0, 255);  // Adjust as needed for your setup
}

void loop() {
  // Read the temperature from the sensor
  int rawValue = analogRead(tempSensorPin);
  double voltage = (rawValue / 1023.0) * 5.0; // Assuming a 5V reference voltage
  Input = (voltage - 0.5) * 100.0; // Convert to degrees Celsius

  // Compute PID control output
  myPID.Compute();

  // Display temperature and control information on OLED
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Temp: ");
  display.print(Input, 2);
  display.println(" C");
  display.print("Setpoint: ");
  display.print(Setpoint, 2);
  display.println(" C");
  display.setCursor(0, 40);
  display.print("Output: ");
  display.print(Output, 2);
  display.display();

  delay(1000); // Update the display every 1 second
}