Arduino雷达测高度+lcd显示屏

#include <LiquidCrystal.h>
LiquidCrystal lcd(12,11,5,4,3,2);
int inputPin=7;
int outputPin=8;
void setup()
{
  Serial.begin(9600);//初始化
  pinMode(inputPin,INPUT);
  pinMode(outputPin,OUTPUT);
  lcd.begin(16,2);
  lcd.print("Welcome");
  delay(1000);  
  char val='9';
 }
 void loop()
 {
    digitalWrite(outputPin,LOW);
    delayMicroseconds(2);
    digitalWrite(outputPin,HIGH);
    delayMicroseconds(10);
    digitalWrite(outputPin,LOW);
    int distance=pulseIn(inputPin,HIGH);
    distance=distance/58;
    lcd.clear();
    lcd.print("Distance");
    lcd.setCursor(0,1);
    lcd.print(distance);
    lcd.print("CM");
    delay(2000);
    char val =Serial.read();
    if(val=="r")
    {
      Serial.println("Hello Arduino");
      Serial.println(val);
      }
  }