/*
  Ultrasonic_sensor.ino
  by Lucas Lim 
  created on 22/4/2020
  Purpose: To activate Ultrasonic sensor and send data to computer

  Ultrasonic sensor Pins:
     VCC: +5V DC
     Trig : Trigger (INPUT) - Arduino Pin9 (PB1)
     Echo: Echo (OUTPUT)    - Arduino Pin10 (PB0)
     GND: GND

  Original code created by Rui Santos, https://randomnerdtutorials.com
 */

#include <SoftwareSerial.h>
SoftwareSerial mySerial(1, 0); // RX, TX

 
const int trigPin = 9;    // Trigger pin
const int echoPin = 10;   // Echo pin
long duration, cm;
int c = 1;
 
void setup() {
  //Initialising Serial Port Communication
  mySerial.begin (9600);

  //Define inputs and outputs
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}
 
void loop() {
  // read from serial for stop character
  if (mySerial.available()>0){
    // read from serial
    c = mySerial.read();
  }
  while (c != 0){    
    // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
    // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    // set the trip pin high high for 10 smicroseconds
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
 
    // Read the signal from the sensor: a HIGH pulse whose
    // duration is the time (in microseconds) from the sending
    // of the ping to the reception of its echo off of an object.
    duration = pulseIn(echoPin, HIGH);
 
    // Convert the time into a distance
    cm = duration *0.034/2;

    mySerial.print(cm);
    mySerial.println();
  
    delay(100); //delay 1 tenth of a sec
  }
}