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AURA GUIDE

Smart Assistive Hat for Visually Impaired People
Саадыг түрүүлж мэдэрнэ. Замыг илүү аюулгүй болгоно.

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Overview

AURA GUIDE is a smart assistive wearable prototype designed to help visually impaired users detect nearby obstacles around the upper body and head level.

The system uses ultrasonic sensors mounted on a hat or helmet to detect obstacles in four directions:

Direction Монгол
Front Урд
Left Зүүн
Right Баруун
Back Ард

Sensor data is sent to a mobile app through Bluetooth. The app analyzes the nearest obstacle and gives Mongolian voice warnings such as:

Урд талд саад байна
Баруун талд ойр саад байна
Зүүн талд маш ойр саад байна

AURA GUIDE is a prototype and concept demonstration. It is not a certified medical or safety device and should not replace a white cane, guide dog, or human assistance.

Why I Built It

I wanted to build a project that connects engineering with a real human problem.

Many assistive devices are expensive, not localized, or not designed with Mongolian language support. AURA GUIDE explores whether a simple wearable system can give obstacle warnings through sensors, Bluetooth communication, and local-language voice feedback.

This project helped me think about more than code:

  • hardware and software working together
  • real-time sensor data
  • Bluetooth communication
  • warning prioritization
  • accessibility-focused UX
  • Mongolian voice feedback
  • safety limitations
  • demo-ready engineering

AURA GUIDE is one of my most important projects because it combines hardware, mobile software, accessibility, product thinking, and real-world impact.

The Problem

For visually impaired people, moving through unfamiliar or crowded spaces can be difficult and risky.

Common challenges include:

Challenge Why It Matters
Obstacles near head or upper body A white cane may not detect higher objects
Crowded environments Users may need faster directional awareness
Expensive assistive devices Many advanced devices are not affordable
Lack of local language support Voice feedback should be understandable
Complex devices Assistive tools should be simple and reliable

AURA GUIDE does not try to replace existing mobility tools.
It is designed as an extra awareness layer.

The Solution

AURA GUIDE is a smart assistive hat prototype.

It uses:

  • 4 ultrasonic sensors for obstacle detection
  • Arduino Uno or ESP32 as the controller
  • HC-05 Bluetooth or ESP32 BLE for communication
  • Mobile app dashboard for status and warning display
  • Mongolian voice warning through phone or Bluetooth earphones
  • Warning engine that chooses the nearest valid obstacle

Key Features

Feature Description
4-direction sensing Detects obstacles in front, left, right, and back
Bluetooth communication Arduino/ESP32 sends real-time distance data to the app
Mongolian voice warning App warns the user with local-language audio feedback
Mobile dashboard Shows distance values and current warning status
Warning engine Chooses nearest obstacle and severity level
Distance filtering Ignores invalid or unsafe sensor readings
Light/Dark theme UI supports both dark and light modes
Branded UI Healthcare-friendly AURA GUIDE visual identity
Demo-ready prototype Suitable for school, engineering, and innovation demos
iOS path ESP32 BLE version planned for iPhone compatibility

Butterfly System Scheme

This diagram shows the whole project as a “butterfly style” architecture: hardware on the left wing, mobile/audio feedback on the right wing, and the Bluetooth protocol as the center body.

flowchart LR
    subgraph LEFT_WING["Sensor Wing"]
        F["Front Sensor<br/>HC-SR04"]
        L["Left Sensor<br/>HC-SR04"]
        R["Right Sensor<br/>HC-SR04"]
        B["Back Sensor<br/>HC-SR04"]
    end

    subgraph BODY["Controller Body"]
        MCU["Arduino Uno / ESP32"]
        FILTER["Distance Filter<br/>Smoothing + Invalid Ignore"]
        FORMAT["Data Protocol<br/>F:80,L:150,R:45,B:200"]
    end

    subgraph RIGHT_WING["Feedback Wing"]
        APP["AURA GUIDE App"]
        ENGINE["Warning Engine<br/>Nearest Obstacle"]
        TTS["Mongolian Voice Warning"]
        USER["User + Bluetooth Earphones"]
    end

    F --> MCU
    L --> MCU
    R --> MCU
    B --> MCU

    MCU --> FILTER
    FILTER --> FORMAT
    FORMAT -->|"Bluetooth / BLE"| APP
    APP --> ENGINE
    ENGINE --> TTS
    TTS --> USER
Loading

System Architecture

flowchart TD
    A["4x HC-SR04 Ultrasonic Sensors"] --> B["Arduino Uno / ESP32"]
    B --> C["Bluetooth Module<br/>HC-05 or ESP32 BLE"]
    C --> D["AURA GUIDE Mobile App"]
    D --> E["Parser<br/>F,L,R,B distance values"]
    E --> F["Warning Engine"]
    F --> G["Text-to-Speech / Audio Warning"]
    G --> H["Bluetooth Earphones"]
Loading

Runtime Data Flow

sequenceDiagram
    participant S as Sensors
    participant M as Arduino / ESP32
    participant B as Bluetooth
    participant A as Mobile App
    participant P as Parser
    participant W as Warning Engine
    participant V as Voice Output
    participant U as User

    S->>M: Measure distances
    M->>M: Filter invalid values
    M->>B: Send F,L,R,B data
    B->>A: Bluetooth data stream
    A->>P: Parse distance values
    P->>W: Valid direction-distance map
    W->>W: Select nearest obstacle
    W->>V: Generate Mongolian warning
    V->>U: Play voice alert
Loading

Hardware Components

Component Quantity Purpose
Arduino Uno / ESP32 1 Main controller
HC-SR04 Ultrasonic Sensor 4 Detect obstacles in 4 directions
HC-05 Bluetooth Module 1 Android Bluetooth Classic connection
ESP32 BLE Optional iPhone/iOS BLE version
Jumper Wires 1 set Sensor wiring
Breadboard / Perfboard 1 Circuit assembly
Power Bank / Battery 1 Portable power supply
Switch 1 Power control
Hat / Helmet 1 Wearable mounting structure
Android Phone / iPhone 1 Mobile app
Bluetooth Earphones 1 Voice feedback output

Wiring Scheme — Arduino Uno + HC-05

This is the Android MVP version using HC-05 Bluetooth Classic.

Sensor Pin Table

Direction TRIG Pin ECHO Pin
Front / Урд D2 D3
Left / Зүүн D4 D5
Right / Баруун D6 D7
Back / Ард D8 D9

HC-05 Wiring

HC-05 Pin Arduino Pin
VCC 5V
GND GND
TXD Arduino RX
RXD Arduino TX through voltage divider

HC-05 RX pin is 3.3V logic. Use a voltage divider between Arduino TX and HC-05 RX.

ASCII Wiring Diagram

        ┌─────────────────────────────────────┐
        │             AURA GUIDE HAT           │
        └─────────────────────────────────────┘

     [Front HC-SR04]      [Left HC-SR04]      [Right HC-SR04]      [Back HC-SR04]
       TRIG → D2            TRIG → D4            TRIG → D6           TRIG → D8
       ECHO → D3            ECHO → D5            ECHO → D7           ECHO → D9
       VCC  → 5V            VCC  → 5V            VCC  → 5V           VCC  → 5V
       GND  → GND           GND  → GND           GND  → GND          GND  → GND

                                  │
                                  ▼
                           ┌─────────────┐
                           │ Arduino Uno │
                           └─────────────┘
                                  │ Serial
                                  ▼
                           ┌─────────────┐
                           │    HC-05    │
                           │ Bluetooth   │
                           └─────────────┘
                                  │
                                  ▼
                           Android App APK

iPhone / ESP32 BLE Version

iPhone apps cannot reliably use HC-05 Bluetooth Classic SPP like Android.

For iOS, the recommended setup is:

4x HC-SR04 → ESP32 → BLE → iPhone App

Recommended BLE device name:

AURA_GUIDE

BLE data remains the same:

F:80,L:150,R:45,B:200

Data Protocol

Arduino / ESP32 sends one line of text:

F:80,L:150,R:45,B:200

Direction Keys

Key Direction Монгол
F Front Урд
L Left Зүүн
R Right Баруун
B Back Ард

Example

F:80,L:150,R:45,B:200

This means:

Direction Distance
Front 80 cm
Left 150 cm
Right 45 cm
Back 200 cm

The nearest obstacle is:

Right = 45 cm

So the app should warn:

Баруун талд ойр саад байна

Warning Logic

AURA GUIDE selects the nearest valid obstacle and generates the warning message.

Distance Severity UI Status Voice Message
0–40 cm Very Close Маш ойр “маш ойр саад байна”
41–80 cm Critical Ойр “ойр саад байна”
81–120 cm Warning Саад “саад байна”
121+ cm Safe Аюулгүй No sound
Invalid / 0 Ignore Холболтгүй No sound

Priority Rule

If multiple sensors detect obstacles at the same time, AURA GUIDE chooses the nearest valid distance.

Input:
F:90,L:40,R:70,B:200

Nearest:
L = 40 cm

Output:
Зүүн талд маш ойр саад байна

Warning Engine Logic

flowchart TD
    INPUT["Bluetooth Data<br/>F:90,L:40,R:70,B:200"] --> PARSE["Parse Direction Values"]
    PARSE --> VALID["Remove Invalid / Zero Values"]
    VALID --> NEAREST["Find Nearest Distance"]
    NEAREST --> LEVEL["Decide Severity Level"]
    LEVEL --> MESSAGE["Build Mongolian Warning"]
    MESSAGE --> AUDIO["Play Voice Alert"]
Loading

Mobile App Screens

1. Splash / Loading Screen

Shows:

  • AURA GUIDE logo
  • tagline
  • healthcare-style loading experience
AURA GUIDE
Smart Assistive Hat
Саадыг түрүүлж мэдэрнэ

2. Main Dashboard

Shows:

  • Bluetooth status
  • current warning
  • 4 sensor cards
  • connect / disconnect
  • settings
AURA GUIDE                          LIVE
Smart Assistive Hat

Bluetooth
HC-05 холбогдсон

ОДООГИЙН АНХААРУУЛГА
Баруун талд ойр саад байна
45 см

┌─────────────┬─────────────┐
│ F Урд       │ L Зүүн      │
│ 80 см       │ 150 см      │
├─────────────┼─────────────┤
│ R Баруун    │ B Ард       │
│ 45 см       │ 200 см      │
└─────────────┴─────────────┘

3. Settings Screen

Includes:

  • light / dark theme
  • audio volume
  • warning sensitivity
  • Bluetooth status
  • app info

Brand Identity

Logo

Recommended logo path:

assets/logo.png

Recommended app icon:

assets/app_icon.png

Brand Colors

Name HEX Usage
Deep Navy #050B18 Dark background
Midnight #0D1B2A Cards and surfaces
Teal #0EA5A1 Primary action / safe status
Aqua #38BDF8 Accent / technology
Amber #FFC857 Warning
Coral #FF6B6B Critical alert
White #F8FAFC Text

Tech Stack

Area Tools / Concepts
Hardware Arduino Uno, ESP32, HC-SR04 sensors
Communication HC-05 Bluetooth Classic, ESP32 BLE
Mobile App Python, Kivy
Android Build Buildozer
Warning Logic Parser, warning engine, severity levels
Audio Mongolian voice feedback / TTS
UI Light/Dark dashboard, sensor cards
Prototype Type Assistive wearable technology

Project Structure

aura_guide_app/
├── main.py
├── app_config.py
├── parser.py
├── warning_engine.py
├── bluetooth_service.py
├── audio_service.py
├── permissions_helper.py
├── buildozer.spec
├── requirements.txt
├── logo.png
├── assets/
│   ├── logo.png
│   ├── icon.png
│   ├── app_icon.png
│   ├── splash.png
│   └── audio/
├── README.md
├── APK_BUILD_STEPS.md
└── ARDUINO_PROTOCOL.md

Quick Start

Run on PC

python main.py

Build Android APK

cd ~/projects/aura_guide_app
source ~/.venvs/buildozer/bin/activate
buildozer -v android debug

APK output:

bin/

Copy APK to Windows:

cp bin/*.apk /mnt/d/bebe_personal/

Arduino / ESP32 Output Test

Before using the app, confirm your board prints data like this:

F:80,L:150,R:45,B:200
F:82,L:149,R:44,B:201
F:85,L:150,R:45,B:200

If the app does not update, check:

  • Bluetooth pairing
  • correct data format
  • newline at the end of each line
  • app permissions
  • HC-05 baud rate
  • sensor power wiring
  • stable battery/power supply

Security Notes

AURA GUIDE does not require:

  • user login
  • cloud server
  • internet data upload
  • personal database

Security recommendations:

  • Change HC-05 default PIN from 1234 / 0000
  • Do not request unnecessary permissions
  • Remove INTERNET permission if not used
  • Use signed release APK for real distribution
  • Keep debug APK only for testing
  • Do not store personal user data without consent

Testing Checklist

Hardware

  • Arduino / ESP32 powers on
  • Front sensor works
  • Left sensor works
  • Right sensor works
  • Back sensor works
  • Bluetooth module powers on
  • Power supply is stable
  • Wires are firmly attached
  • Sensors are mounted securely

Firmware

  • Serial output format is correct
  • Invalid values are ignored
  • Sensors are read one by one
  • Sensor interference is reduced
  • Output updates smoothly

App

  • App opens successfully
  • Splash screen appears
  • Bluetooth connects
  • Sensor values update
  • Warning message is correct
  • Voice warning works
  • Light/dark theme works
  • App does not crash

Real Environment

  • Front wall detected
  • Left obstacle detected
  • Right obstacle detected
  • Back obstacle detected
  • Person approaching detected
  • Chair / box detected
  • Corridor test completed
  • False warnings are acceptable
  • Demo flow works

Safety Disclaimer

AURA GUIDE is a prototype assistive technology project.

It does not replace:

  • white cane
  • guide dog
  • human guide
  • medical/safety-certified mobility device

Limitations:

  • Ultrasonic sensors may fail on soft, angled, thin, or glass surfaces.
  • Stairs, holes, and low obstacles may not be detected reliably.
  • Sensor angle and mounting quality affect accuracy.
  • Bluetooth connection may disconnect.
  • Battery or power issues can stop the system.
  • The prototype should be used only for demos and controlled testing.

Recommended demo explanation:

Энэ бол харааны бэрхшээлтэй хүнд туслах зорилготой prototype бөгөөд одоогоор concept demonstration түвшинд байна.

Demo Flow

Recommended demo flow:

Step What to Show
1 Explain the accessibility problem
2 Show the hat / sensor concept
3 Show Arduino or ESP32 sending data
4 Show Bluetooth connection
5 Show mobile dashboard updating
6 Move obstacle near one direction
7 Trigger Mongolian voice warning
8 Explain safety limitation and future plan

Demo Script

Манай төслийн нэр AURA GUIDE.

Энэ нь харааны бэрхшээлтэй хүнд ойр орчны саадыг урьдчилан мэдрүүлж,
дуут анхааруулга өгөх smart assistive hat prototype юм.

Малгай дээр 4 ширхэг ultrasonic sensor байрласан:
урд, зүүн, баруун, ард.

Arduino эдгээр sensor-оос зай хэмжиж, Bluetooth module-оор Android app руу data илгээдэг.

App нь data-г real-time уншаад хамгийн ойр байгаа саадыг тодорхойлж,
Bluetooth чихэвчээр Монгол хэлээр анхааруулга өгнө.

Жишээлбэл, баруун талд ойр саад байвал:
“Баруун талд ойр саад байна” гэж хэлнэ.

Энэ prototype нь цагаан таягийг орлохгүй.
Харин ойр орчны саадыг нэмэлтээр мэдрүүлэх concept demonstration юм.

What I Learned

While building AURA GUIDE, I learned that assistive technology needs careful design.

The hardest parts were:

  • thinking about real user safety
  • deciding which obstacle should be prioritized
  • parsing real-time Bluetooth data
  • designing warning severity levels
  • making feedback simple and understandable
  • thinking about local language support
  • connecting hardware, software, and UX together
  • explaining limitations honestly

This project helped me understand that engineering is not only about building something impressive.
It is also about building something useful, understandable, and human.

Current Limitations

Limitation Future Fix
Prototype concept stage Build a stronger physical prototype
Limited hardware testing Test with real sensors more consistently
Basic warning logic Add better smoothing and calibration
Bluetooth may disconnect Add reconnect logic and status alerts
No full iOS app yet Build ESP32 BLE version
No vibration feedback yet Add haptic motor warnings
Limited user testing Get feedback from accessibility groups
Voice feedback can improve Add offline Mongolian voice pack

Roadmap

  • Better enclosure / 3D printed sensor holders
  • ESP32 BLE version for iPhone
  • Vibration feedback
  • Battery level indicator
  • Emergency button
  • GPS location sharing
  • Fall detection
  • Camera + AI object detection
  • Offline voice pack
  • Release signed APK
  • Real-world testing in controlled environments
  • Accessibility feedback from real users

Team Roles

Role Responsibility
Hardware Engineer Sensor wiring, mounting, power
Firmware Developer Arduino/ESP32 code, sensor logic
Mobile App Developer App UI, Bluetooth, warning engine
Testing Support Test log, demo, documentation

Portfolio Summary

AURA GUIDE is a smart assistive wearable prototype for visually impaired users.

It demonstrates:

  • hardware/software integration
  • Bluetooth communication
  • real-time sensor parsing
  • warning engine design
  • Mongolian voice feedback
  • accessibility-focused UX
  • mobile app dashboard design
  • safety-aware product thinking
  • real-world engineering documentation

This project represents my interest in building technology that is not only smart, but also useful, local, and human.

Support This Project

If you like this project:

AURA GUIDE
Саадыг түрүүлж мэдэрнэ. Замыг илүү аюулгүй болгоно.

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