irtxrx.c

int recv = 13;
int trans = 3;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(recv, INPUT);
  pinMode(trans, OUTPUT);

  digitalWrite(trans, HIGH);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(!digitalRead(recv)) {
    Serial.println("Read");
    delay(100);
  }
}