#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// LCD Configuration
LiquidCrystal_I2C lcd(0x27, 16, 2); // Change address if needed

// Rotary Encoder Pins
const int encoderPinA = 18;  
const int encoderPinB = 19;

// Potentiometer Pin
const int potPin = 34;  // Analog input

// Encoder Variables
volatile int pulseCount = 0; 
unsigned long lastTime = 0;
float rpm = 0;

// Encoder specification
const int pulsesPerRevolution = 20; 

// Interrupt Service Routine for Encoder
void IRAM_ATTR encoderISR() {
  pulseCount++;
}

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

  // LCD Setup
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("RPM + POT Monitor");

  // Encoder Pins
  pinMode(encoderPinA, INPUT_PULLUP);
  pinMode(encoderPinB, INPUT_PULLUP);

  // Attach interrupt to encoder A pin
  attachInterrupt(digitalPinToInterrupt(encoderPinA), encoderISR, RISING);

  lastTime = millis();
}

void loop() {
  unsigned long currentTime = millis();

  // Read potentiometer value (0 - 4095)
  int potValue = analogRead(potPin);

  // Map potentiometer to simulated RPM range
  int simulatedRPM = map(potValue, 0, 4095, 0, 5000); 

  // Calculate actual encoder RPM every second
  if (currentTime - lastTime >= 1000) {
    rpm = (pulseCount / (float)pulsesPerRevolution) * 60.0;
    pulseCount = 0;
    lastTime = currentTime;

    // Print to Serial Monitor
    Serial.print("Encoder RPM: ");
    Serial.print(rpm);
    Serial.print(" | Pot Value: ");
    Serial.print(potValue);
    Serial.print(" | Simulated RPM: ");
    Serial.println(simulatedRPM);

    // Display on LCD
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("EncRPM:");
    lcd.print(rpm, 0);

    lcd.setCursor(0, 1);
    lcd.print("PotRPM:");
    lcd.print(simulatedRPM);
  }
}