#include <SoftwareSerial.h>

SoftwareSerial Serial_sw(0, 1); // tx, rx

#define echoPin 9 // echo conencted to pb1
#define trigPin 10 // trigger connected to pb0

int duration;
byte distance;

void setup()
{
Serial_sw.begin(9600);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
}

void loop()
{
digitalWrite(trigPin, LOW);
delayMicroseconds(1);

digitalWrite(trigPin, HIGH);
delayMicroseconds(10);

digitalWrite(trigPin, LOW);

duration = pulseIn(echoPin, HIGH);
distance = duration / 58;
Serial_sw.write(distance);

delay(100);
}