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

#define ENCODER_A 32  // CLK pin
#define ENCODER_B 33  // DT pin
#define PULSES_PER_REV 20  // Adjust based on your encoder specs

volatile int pulse_count = 0;
unsigned long last_time = 0;
float rpm = 0;

// LCD initialization (address 0x27, 16 columns, 2 rows)
LiquidCrystal_I2C lcd(0x27, 16, 2); 

void IRAM_ATTR countPulses() {
  pulse_count++;
}

void setup() {
  Serial.begin(115200);
  pinMode(ENCODER_A, INPUT_PULLUP);
  pinMode(ENCODER_B, INPUT_PULLUP);
  
  // Attach interrupt to count pulses on rising edge
  attachInterrupt(digitalPinToInterrupt(ENCODER_A), countPulses, RISING);
  
  // Initialize the LCD
  lcd.begin(16, 2);
  lcd.setBacklight(1);  // Turn on the backlight (if available)
  lcd.print("RPM Monitor");
  delay(2000);  // Display "RPM Monitor" for 2 seconds
  lcd.clear();
}

void loop() {
  unsigned long current_time = millis();
  
  if (current_time - last_time >= 1000) {  // Update RPM every 1 second
    rpm = (pulse_count / (float)PULSES_PER_REV) * 60.0;  // Convert to RPM
    pulse_count = 0;  // Reset pulse count
    last_time = current_time;
    
    // Display RPM on Serial Monitor
    Serial.print("RPM: ");
    Serial.println(rpm);
    
    // Display RPM on LCD
    lcd.clear();  // Clear the display
    lcd.setCursor(0, 0);  // Set cursor to the first row
    lcd.print("RPM: ");
    lcd.print(rpm);  // Display the RPM value
  }
}