Ultrasound

int trigger = 7;
int echo = 6;

void setup() {
  // put your setup code here, to run once:
  pinMode(trigger, OUTPUT);
  pinMode(echo, INPUT);
  Serial.begin(9600);
  pinMode(11, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trigger, LOW);
  delayMicroseconds(2);
  digitalWrite(trigger, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigger, LOW);

  long time = pulseIn(echo, HIGH);

  long distance = time * 0.034 / 2;

  Serial.println(distance, 3);
  Serial.println(distance % 256, 3);


  analogWrite(11, distance % 256);

  delay(300);

}