#include <PID_v1.h>

// Pin Definitions
const int stepPin = 14; 
const int dirPin = 12;
const int potPin = 34;  // Potentiometer connected to ADC pin on ESP32 (e.g., GPIO34)

// PID variables
double setpoint = 7200; // Target steps per minute (36 RPM)
double input = 0;       // Current step rate (from potentiometer feedback)
double output = 0;      // PID output (to adjust step timing)

// PID tuning parameters
double Kp = 2.0;        // Proportional gain
double Ki = 5.0;        // Integral gain
double Kd = 1.0;        // Derivative gain

// Create PID controller
PID myPID(&input, &output, &setpoint, Kp, Ki, Kd, DIRECT);

void setup() {
  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);

  // Initialize the PID controller
  myPID.SetMode(AUTOMATIC);
  myPID.SetOutputLimits(500, 2000);  // Limit PID output (delay in microseconds)
  
  // Initialize serial communication
  Serial.begin(115200);
}

void loop() {
  // Read the potentiometer value
  int potValue = analogRead(potPin);  // ESP32 ADC returns values from 0 to 4095
  input = map(potValue, 0, 4095, 0, 7200); // Map ADC value to steps per minute (0 to 7200)

  // Compute PID output
  myPID.Compute();

  // Set motor direction (forward or reverse)
  digitalWrite(dirPin, HIGH);

  // Generate steps with delay from PID output
  digitalWrite(stepPin, HIGH);
  delayMicroseconds(output);  // Delay controlled by PID output
  digitalWrite(stepPin, LOW);
  delayMicroseconds(output);

  // Print values for graphing
  Serial.print("Input: ");
  Serial.print(input);       // Current speed (steps per minute)
  Serial.print(" Setpoint: ");
  Serial.print(setpoint);    // Desired speed (36 RPM = 7200 steps/minute)
  Serial.print(" Output: ");
  Serial.println(output);    // PID output (delay for motor step timing)
}