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

LiquidCrystal_I2C mylcd(0x27,16,2);
volatile int juli;

float checkdistance_3_2() {
  digitalWrite(3, LOW);
  delayMicroseconds(2);
  digitalWrite(3, HIGH);
  delayMicroseconds(10);
  digitalWrite(3, LOW);
  float distance = pulseIn(2, HIGH) / 58.00;
  delay(10);
  return distance;
}

void setup(){
  mylcd.init();
  mylcd.backlight();
  juli = 0;
  pinMode(3, OUTPUT);
  pinMode(2, INPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
}

void loop(){
  juli = checkdistance_3_2();
  if (juli <= 20) {
    mylcd.setCursor(0, 0);
    mylcd.print(String("juli") + String(juli));
    mylcd.setCursor(0, 1);
    mylcd.print("ting!ting!ting!!");
    tone(7,3951);
    digitalWrite(8,HIGH);
    delay(60);
    mylcd.clear();
    noTone(7);
    delay(60);

  } else if (juli <= 40) {
    mylcd.setCursor(0, 0);
    mylcd.print(String("juli") + String(juli));
    mylcd.setCursor(0, 1);
    mylcd.print("tingche");
    tone(7,3951);
    delay(100);
    noTone(7);
    digitalWrite(8,HIGH);
    delay(160);
    mylcd.clear();
    digitalWrite(8,LOW);
    delay(160);
  } else if (juli <= 60) {
    mylcd.setCursor(0, 0);
    mylcd.print(String("juli") + String(juli));
    mylcd.setCursor(0, 1);
    mylcd.print("xiaoxindian");
    tone(7,3951);
    delay(260);
    noTone(7);
    digitalWrite(8,HIGH);
    delay(330);
    digitalWrite(8,LOW);
    delay(330);
    mylcd.clear();
  }

}