#include <LiquidCrystal.h>
#define trg A0
#define ech A1
int dis =0;
int t=0;
int v=0;//vlocity 
int vx =0;//delta x
int a=200; //delay time 
int x [10]; // distance array or memmory
int time [10];// time array 
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
int s =0 ; //step
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
void setup() {
  lcd.begin(16, 2);
  lcd.print("distance: ");
  Serial.begin(9600);
  pinMode(trg, OUTPUT);
  pinMode(ech, INPUT);
}
void loop() {
  /*-------------*/
  digitalWrite(trg, LOW);
  delayMicroseconds(5);
  digitalWrite(trg, HIGH);
  delayMicroseconds(10);
  digitalWrite(trg, LOW);
  t=pulseIn(ech,HIGH);
  dis=t/57;
  dis=(dis*.975)+1;//معامل تصحيح الاشاره
  Serial.println(dis);
  x[s]=dis;
  //delay(200);
  vx=x[s]-x[s+1];//delta x
  v=abs(vx)/.1;
  delay(100);
  /*-------------*/
  s=s+1;
  lcd.setCursor(9,0);
  lcd.print(dis);
  lcd.print("  ");
  lcd.setCursor(10,1);
  lcd.print("v");
  lcd.print(v);
  lcd.print("       ");
  if (s==9){
    s=0;
  }
  if(dis<=10){
    lcd.setCursor(0,1);
    lcd.print("warnning");
  }else{
    lcd.setCursor(0,1);
    lcd.print("         ");
  }
  if (v==(dis*10)){//it is imposible state and only happen in error of code
    v=0;
    lcd.setCursor(10,1);
    lcd.print("v");
    lcd.print(v);
    lcd.print("       ");  
  }

  }