#include <LiquidCrystal.h>
#include "HX711.h"

// HX711 pins
#define DT A0
#define SCK A1

// LCD: RS, E, D4, D5, D6, D7
LiquidCrystal lcd(PB0, PB1, PB10, PB11, PB12, PB13);

// Pins for input/output
const int tareButtonPin = PA2;
const int ledPin = PA3;

// HX711 object
HX711 scale;

// ✅ Updated calibration factor
float calibration_factor = 1.0;

void setup() {
  Serial.begin(9600);
  pinMode(tareButtonPin, INPUT_PULLUP);  // Button uses pull-up
  pinMode(ledPin, OUTPUT);

  lcd.begin(16, 2);
  lcd.print("Weighing Scale");
  delay(1500);
  lcd.clear();

  // Start HX711 with calibration
  scale.begin(DT, SCK);
  scale.set_scale(calibration_factor);
  scale.tare(); // Zero out the scale

  lcd.setCursor(0, 0);
  lcd.print("Taring...");
  delay(1500);
  lcd.clear();

  Serial.println("Scale ready.");
  Serial.print("Calibration factor: ");
  Serial.println(calibration_factor);
}

void loop() {
  // Tare on button press
  if (digitalRead(tareButtonPin) == LOW) {
    lcd.setCursor(0, 0);
    lcd.print("Taring...");
    scale.tare();
    delay(1500);
    lcd.clear();
  }

  // Get average weight reading
  float weight = scale.get_units(5); // average of 5 readings

  // Show weight on LCD
  lcd.setCursor(0, 0);
  lcd.print("Weight:       ");
  lcd.setCursor(8, 0);
  lcd.print(weight, 1); // 1 decimal point
  lcd.print(" g");

  // LED: ON if weight present
  if (abs(weight) < 1.0) {
    digitalWrite(ledPin, LOW); // weight is near zero
  } else {
    digitalWrite(ledPin, HIGH); // weight detected
  }

  delay(500);
}