#include <HX711.h>
#include <Servo.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define DT 3
#define SCK 2

HX711 scale;
Servo gate;

LiquidCrystal_I2C lcd(0x27, 16, 2);

// Calibration factor
float calibration_factor = -7050;

void setup()
{
  Serial.begin(9600);

  lcd.init();
  lcd.backlight();

  gate.attach(9);

  scale.begin(DT, SCK);

  scale.set_scale(calibration_factor);
  scale.tare();

  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Smart Bridge");
  delay(200);
}

void loop()
{
  float weight = scale.get_units(10);

  if(weight < 0)
    weight = 0;

  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Wt:");
  lcd.print(weight,1);
  lcd.print("kg");

  if(weight < 5.0)
  {
    gate.write(90); // Open gate

    lcd.setCursor(0,1);
    lcd.print("ACCESS GRANTED");
  }
  else
  {
    gate.write(0); // Close gate

    lcd.setCursor(0,1);
    lcd.print("ACCESS DENIED ");
  }

  Serial.print("Weight: ");
  Serial.println(weight);

  delay(10);
}