#include <SoftwareSerial.h>
int Tx=2; //블루투스 전송
int Rx=3; //블루투스 수신
SoftwareSerial btSerial(Tx, Rx);
void setup() {
Serial.begin(9600);
btSerial.begin(9600);
//오르막길 센서(distance4)
pinMode(9, OUTPUT);
pinMode(8, INPUT);
//발바닥 센서(distance1)
pinMode(7,OUTPUT);
pinMode(6,INPUT);
//전방 센서(distance2)
pinMode(5, OUTPUT);
pinMode(4, INPUT);
//내리막길 센서(distance3)
pinMode(13,OUTPUT);
pinMode(12, INPUT);
}
void loop() {
//발바닥 센서 측정 시작한 후, 거리값 계산
digitalWrite(7, LOW);
digitalWrite(6, LOW);
delayMicroseconds(2);
digitalWrite(7,HIGH);
delayMicroseconds(10);
digitalWrite(7,LOW);
unsigned long duration1 = pulseIn(6, HIGH);
float distance1 = ((float)(340L*duration1)/10000)/2.0;

//발바닥 센서에서 측정한 값이 3.8cm 이하일 때, 나머지 센서(전방 센서, 오르막길 센서, 내리막길 센서) 측정 시작한 후 거리값 계산
if(distance1<3.8f){
Serial.println(“Under 10cm”);
digitalWrite(9, LOW);
digitalWrite(8, LOW);
delayMicroseconds(2);
digitalWrite(9, HIGH);
delayMicroseconds(10);
digitalWrite(8,LOW);
unsigned long duration4 = pulseIn(8, HIGH);
float distance4 = ((float)(340L*duration4)/10000)/2.0;

digitalWrite(5, LOW);
digitalWrite(4, LOW);
delayMicroseconds(2);
digitalWrite(5, HIGH);
delayMicroseconds(10);
digitalWrite(5,LOW);
unsigned long duration2 = pulseIn(4, HIGH);
float distance2 = ((float)(340L*duration2)/10000)/2.0;

digitalWrite(13, LOW);
digitalWrite(12, LOW);
delayMicroseconds(2);
digitalWrite(13, HIGH);
delayMicroseconds(10);
digitalWrite(13,LOW);
unsigned long duration3 = pulseIn(12, HIGH);
float distance3 = ((float)(340L*duration3)/10000)/2.0;
Serial.println(distance2);
Serial.println(distance3);
Serial.println(distance4);
//센서가 측정 가능한 거리값을 과도하게 벗어나는 오류값을 받지 않기 위해 3500cm 이하의 값만 안드로이드 스튜디오로 전송
if (distance2<3500&&distance3<3500&&distance4<3500){
btSerial.print(distance2);
btSerial.print(‘,’);
btSerial.print(distance3);
btSerial.print(‘,’);
btSerial.print(distance4);
btSerial.println();
}
}
else{

}
delay(1000);
}

Mainactivity.java
package com.example.sinbal;
import android.app.Activity;
import android.content.Intent;
import android.widget.TextView;
import android.widget.Toast;
import app.akexorcist.bluetotohspp.library.BluetoothSPP;
import app.akexorcist.bluetotohspp.library.BluetoothState;
import app.akexorcist.bluetotohspp.library.DeviceList;
import android.media.MediaPlayer;
import android.bluetooth.BluetoothAdapter;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
private BluetoothSPP bt;
int size;
boolean blockDetected = false;
boolean wallDetected = false;
boolean downhillDetected = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = getIntent(); //변수 받아오기 추가 부분
size = intent.getIntExtra(“size”,0);
bt = new BluetoothSPP(this); //Initializing
if (!bt.isBluetoothAvailable()) { //블루투스 사용 불가
Toast.makeText(getApplicationContext()
, “Bluetooth is not available”
, Toast.LENGTH_SHORT).show();
finish();
}
bt.setOnDataReceivedListener(new BluetoothSPP.OnDataReceivedListener() {
TextView distance22 = findViewById(R.id.distance2); //텍스트뷰를 통해 초음파 센서 값 받아오기
TextView distance33 = findViewById(R.id.distance3);
TextView distance44 = findViewById(R.id.distance4);
double finalSize = MainActivity.this.size/10*2.5*3; // final size를 사용자의 보폭 기준 3걸음으로 설정
public void onDataReceived(byte[] data, String message) { //데이터 수신용 코드 추가
String[] array = message.split(“,”);
distance22.setText(array[0].concat(“cm”));
distance33.setText(array[1].concat(“cm”));
distance44.setText(array[2].concat(“cm”));
double distance2 = Double.parseDouble(array[0]); //초음파센서값 3개 array 형식으로 안드로이드 스튜디오에 받아오기
double distance3 = Double.parseDouble(array[1]);
double distance4 = Double.parseDouble(array[2]);
double hypotenuse = distance2/0.93969; //오르막센서 각도를 20도로 설정. 밑변 길이를 cos20으로 나눈 값, 대각선 길이
//벽 & 오르막
if(distance4<400){
if(distance4>hypotenuse){ //오르막 센서값과 전방센서값이 직각삼각형 형성하지 않을 경우 오르막으로 인식
//오르막
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.uphill);
mp.start();
}
else{ // 오르막 센서값과 전방센서값이 직각삼각형 형성할 경우 벽으로 인식
//벽
if(distance2 < finalSize){
if(!wallDetected) { //벽 중복 알람 방지
wallDetected = true;
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.wall);
mp.start();
}
if(distance2 < 15) { //근접 경보
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.close);
mp.start();
}
}
else {
wallDetected = false;
}
}
}
//장애물
else{ // 오르막 센서가 감지되지 않을 경우, 전방센서값은 측정되는 경우.
if(distance2< finalSize){
if(!blockDetected) { //장애물 중복 알람 방지
blockDetected = true;
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.block);
mp.start();
}
if(distance2<15) { //근접 경보
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.close);
mp.start();
}
}
else {
blockDetected = false;
}
}
//내리막센서가 일정 값 이상이 나올 경우
//내리막
if(distance3>100) {
if (!downhillDetected) {
downhillDetected = true; //내리막길 중복 알람 방지
final MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.downhill);
// mp.start();
}
else {
downhillDetected = false;
}
}
});
bt.setBluetoothConnectionListener(new BluetoothSPP.BluetoothConnectionListener() { //연결됐을 때
public void onDeviceConnected(String name, String address) {
Toast.makeText(getApplicationContext()
, “Connected to ” + name + “\n” + address
, Toast.LENGTH_SHORT).show();
}
public void onDeviceDisconnected() { //연결해제
Toast.makeText(getApplicationContext()
, “Connection lost”, Toast.LENGTH_SHORT).show();
}
public void onDeviceConnectionFailed() { //연결실패
Toast.makeText(getApplicationContext()
, “Unable to connect”, Toast.LENGTH_SHORT).show();
}
});
Button btnConnect = findViewById(R.id.btnConnect); //연결시도
btnConnect.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (bt.getServiceState() == BluetoothState.STATE_CONNECTED) {
bt.disconnect();
} else {
Intent intent = new Intent(getApplicationContext(), DeviceList.class);
startActivityForResult(intent, BluetoothState.REQUEST_CONNECT_DEVICE);
}
}
});
}
public void onDestroy() {
super.onDestroy();
bt.stopService(); //블루투스 중지
}
public void onStart() {
super.onStart();
if (!bt.isBluetoothEnabled()) { //
Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(intent, BluetoothState.REQUEST_ENABLE_BT);
} else {
if (!bt.isServiceAvailable()) {
bt.setupService();
bt.startService(BluetoothState.DEVICE_OTHER); //DEVICE_ANDROID는 안드로이드 기기 끼리
setup();
}
}
}
public void setup() {
Button btnSend = findViewById(R.id.btnSend); //데이터 전송
btnSend.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
bt.send(“Text”, true);
}
});
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == BluetoothState.REQUEST_CONNECT_DEVICE) {
if (resultCode == Activity.RESULT_OK)
bt.connect(data);
} else if (requestCode == BluetoothState.REQUEST_ENABLE_BT) {
if (resultCode == Activity.RESULT_OK) {
bt.setupService();
bt.startService(BluetoothState.DEVICE_OTHER);
setup();
} else {
Toast.makeText(getApplicationContext()
, “Bluetooth was not enabled.”
, Toast.LENGTH_SHORT).show();
finish();
}
}
super.onActivityResult(requestCode, resultCode, data);
} }

Initial.java
package com.example.sinbal;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import androidx.appcompat.app.AppCompatActivity;
public class initial extends AppCompatActivity {
Button button;
EditText userSize;
CheckBox checkSize;
SharedPreferences UserInfo;
SharedPreferences.Editor editor;
public static final int sub = 1001; /*다른 액티비티를 띄우기 위한 요청코드(상수)*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_initial);
button = (Button) findViewById(R.id.alert);
userSize = (EditText) findViewById(R.id.inputSize);
checkSize = (CheckBox) findViewById(R.id.checkSize);
checkSize.setChecked(true);
UserInfo = getSharedPreferences(“UserInfo”, 0);
editor = UserInfo.edit();
//사용자에게 발사이즈 입력받는 변수 설정
final int inputSizeValue = UserInfo.getInt(“inputSize”, 0);
if (inputSizeValue > 0) {
userSize.setText(Integer.toString(inputSizeValue));
}
Button button = findViewById(R.id.start); /*페이지 전환버튼*/
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(), MainActivity.class); //변수 받아오기 추가 부분
// Intent intent = new Intent(this, MainActivity.class);
String SizeValue = userSize.getText().toString();
if (!SizeValue.isEmpty()) {//Empty 아닐 때만 실행
int inputSizeValue = Integer.parseInt(SizeValue);
intent.putExtra(“size”, inputSizeValue);
startActivity(intent);//액티비티 띄우기
}
}
});
}
public void onPause() {
super.onPause();
if (checkSize.isChecked()) {
String sSize = userSize.getText().toString();
if (!sSize.isEmpty()) {
editor.putInt(“inputSize”, Integer.parseInt(sSize));
}
} else {
editor.putInt(“inputSize”, 0);
}
editor.commit();
}
public void onStart(){
super.onStart();
button.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v) {
Intent intent = new Intent(initial.this, PopupActivity.class);
startActivity(intent);
}
});
}
}