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

#define DT_PIN  4
#define SCK_PIN  5
#define TRIG_PIN 7
#define ECHO_PIN 6
HX711 scale;

NewPing sonar(TRIG_PIN, ECHO_PIN);

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  scale.begin(DT_PIN, SCK_PIN);
  scale.set_scale(420);
  scale.tare();
  sonar.ping();
  lcd.begin(16, 2);
  lcd.backlight();
  delay(1000);
}

void loop() {
  float weight = scale.get_units(10);
  unsigned int uS = sonar.ping();
  float height = uS / US_ROUNDTRIP_CM / 100.0;

  if (height > 0) {
    float bmi = weight / (height * height);
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Weight: ");
    lcd.print(weight, 2);
    lcd.print(" kg");
    lcd.setCursor(0, 1);
    lcd.print("Height: ");
    lcd.print(height, 2);
    lcd.print(" m");
    delay(3000);

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("BMI:");
    lcd.setCursor(0, 1);
    lcd.print(bmi, 1);
    lcd.print(" kg/m^2");
    delay(3000);
  } else {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Height error");
    delay(3000);
  }
  delay(5000);
}