#include <SoftwareSerial.h>
#define rxPin 0
#define txPin 1
SoftwareSerial my_serial(rxPin, txPin);

int light_pulse = 0;
int photo_transistor = PA2;
int reading = 0;

void setup() {
  pinMode(photo_transistor,INPUT);
  my_serial.begin(9600);
}

void loop(){
  reading = analogRead(photo_transistor);
  my_serial.println("Sensing light:");
  my_serial.println(reading);
  
  delay(100);                            
}