Can I set pins 27, 28 to digital INPUT OUTPUT ?

Having troubles settings 27, 28 to digital INPUT OUTPUT. I want to attach ultrasound sensor, but it just doesnt work.

int dypOutputPin = 28; // TRIG
int dypInputPin = 27;  // ECHO


void setup() {
  pinMode(dypOutputPin, OUTPUT);
  pinMode(dypInputPin, INPUT);

void loop() {

  //scan forward USS (ultrasonic sensor)
  digitalWrite(dypOutputPin, LOW);
  digitalWrite(dypOutputPin, HIGH);
  digitalWrite(dypOutputPin, LOW);   
  // the distance is proportional to the time interval
  // between HIGH and LOW
  distance = pulseIn(dypInputPin, HIGH,50);
  cm = distance/58;  

Arduino UNO R3

As I understand it, you should either label those pins 18 and 19, or A1 and A0. They are pins 27 and 28 on the microprocessor, but the Arduino terminology prevails.

Why not name the pin variables "ECHO" and "TRIG"? Wouldn't that make more sense than the variable names you are using now?

Which Arduino board are you using?

Never mind, it was not obvious that physical pins 28,27 are actually IDE pins 19, 18