#include <LiquidCrystal.h>
LiquidCrystal lcd(PA6, PA5, PA4, PA3, PA2, PA1);
const int trigP = PB8;
const int echoP = PB9;
const int ledPin = PC13; // STM32 internal LED
long duration;
int distanceCm;
float distanceM;

void setup() {
  lcd.begin(16, 2);
  lcd.print(" US Range Meter ");
  lcd.setCursor(0, 1);
  lcd.print("Cm:           "); // Reserve space for both units
  pinMode(trigP, OUTPUT);
  pinMode(echoP, INPUT);
  pinMode(ledPin, OUTPUT);
  delay(1000);
}

void loop() {
  digitalWrite(trigP, LOW);
  delayMicroseconds(2);
  digitalWrite(trigP, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigP, LOW);
  duration = pulseIn(echoP, HIGH);
  distanceCm = duration * 0.034 / 2;
  distanceM = distanceCm / 100.0; // Convert to meters

  // Check if distance is below 10 cm
  if (distanceCm < 10) {
    digitalWrite(ledPin, HIGH); // Turn on LED
    lcd.setCursor(0, 1);
    lcd.print("WARNING! <10cm ");
  } else {
    digitalWrite(ledPin, LOW); // Turn off LED
    // Clear and display distance
    lcd.setCursor(0, 1);
    lcd.print("Cm:");
    lcd.setCursor(3, 1);
    lcd.print("      "); // Clear old data
    lcd.setCursor(3, 1);
    lcd.print(distanceCm);
    lcd.print(" ");
    lcd.setCursor(11, 1);
    lcd.print("M:");
    lcd.print(distanceM, 2); // 2 decimal places
  }

  delay(1000);
}