#include <LiquidCrystal.h>
#include <Servo.h>
#include <EEPROM.h>

const int rs = 33, en = 35, d4 = 25, d5 = 27, d6 = 29, d7 = 31;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

Servo door;

int trig = 34;
int echo = 32;
int threshold = 100;

float receiveSend() {

  delayMicroseconds(24000);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  float time = pulseIn(echo, HIGH);
  float distance = (0.5 * time  * 0.00034);
  return(distance);

}

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.setCursor(0, 0);
  door.attach(39);
  threshold = EEPROM.read(0);
}

void loop() {

  //threshold = EEPROM.read(0);
  if (Serial.available() > 0) {
    int enteredThreshold = Serial.readStringUntil("\n").toInt();
    EEPROM.write(0, enteredThreshold);
  }
  Serial.println(threshold);
  Serial.println("\n");

  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  float time = pulseIn(echo, HIGH);
  int distance = (0.5 * time  * 0.034);

  if (distance != 0.00) {
    int distancePrint = distance;
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Distance: ");
    lcd.print(distance);
    lcd.print("cm"); 

    if (distance < threshold) {
      door.write(90);
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Distance: ");
      lcd.print(distance);
      lcd.print("cm");
      lcd.setCursor(0, 1);
      lcd.print("Open");  
    }
    else if (distance >= 100) {
      door.write(0);
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Distance: ");
      lcd.print(distance);
      lcd.print("cm");
      lcd.setCursor(0, 1);
      lcd.print("Closed");  
    }
  }
}