#include <SoftwareSerial.h>
#define serial_in 2
#define serial_out 0
#define pinr 4
SoftwareSerial Serial(serial_in,serial_out);

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(pinr, INPUT);
  Serial.println("Testing digital sensor");
}

void loop() {
  // put your main code here, to run repeatedly:
    if(!digitalRead(pinr)){
      Serial.println("Here I am");
    }
}