int echo_pin = 2;
int trig_pin = 3;
int time;
int distance;

void setup() {
  // put your setup code here, to run once:
  pinMode(trig_pin, OUTPUT);
  pinMode(echo_pin, INPUT);
  Serial.begin(9600);
  Serial.print("ultrasonic distance:");
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trig_pin, LOW);
  digitalWrite(trig_pin, HIGH);
  time = pulseIn(echo_pin, HIGH);
  distance = time*0.0172;
  Serial.print("time:");
  Serial.print(time);
  Serial.print("microseconds");
  delay(1000);
  Serial.print("distance:");
  Serial.print(distance);
  Serial.print("cm");
  delay(1000);
}