🚀 BleLink - Bluetooth LE App

An Android app built with Jetpack Compose, Kotlin that enables Bluetooth Low Energy (BLE) communication. The app allows users to scan for BLE devices, connect, explore services, characteristics, and descriptors, and perform read/write operations.

🛠 Features

• 🔍 Scan for nearby Bluetooth LE devices
• 🔗 Connect and disconnect from BLE devices
• 📜 Discover services, characteristics, and descriptors
• 📡 Read and write data from BLE characteristics
• 🔄 Subscribe to characteristic notifications and indications
• 🔒 Uses Google Accompanist for runtime permissions
• 🏗 Modular architecture with Hilt for Dependency Injection
• 📱 Modern UI with Jetpack Compose

📸 Screenshots

📦 Tech Stack

• Language: Kotlin
• UI Framework: Jetpack Compose
• Dependency Injection: Hilt
• Permissions Handling: Google Accompanist
• Bluetooth Communication: Android BLE API
• Architecture: MVVM

🔍 UUIDs & Manufacturer Ids Resolution

• The app currently resolves some Xiaomi Mi Band 4C services, characteristics, and descriptor UUIDs to their related functions.
  • For example, UUID 00001800-0000-1000-8000-00805f9b34fb corresponds to the Generic Access service.
• The app also resolves a few manufacturer IDs to their respective names.

🛠️ How to Edit Known UUIDs

If you want to modify the known UUIDs for your BLE device:

1. Open the following file in the app’s source code:

   /core/ble/util/BleResolvers.kt
   

2. Edit the maps inside the file to update the UUID-function mappings or manufacturer ID resolutions.

🔹 Important Notes

• The app assumes that BluetoothGattCharacteristic UUIDs are unique.It does not perform additional checks for duplicate UUIDs.
• The app does not verify descriptor permissions before performing read or write operations.

⚠ Why?

The Android SDK’s getPermissions() method always returns false, meaning the permission flags often do not accurately reflect whether a descriptor is actually readable or writable. As a result, checking permissions before performing operations may lead to unnecessary restrictions or incorrect assumptions.

🛠️ How to Enable Descriptor Permission Checks

If you still want to enforce permission checks for descriptors:

1. Navigate to the following file in the app's source code:

   /core/ble/model/modelmapper/BluetoothGattDescriptorModelMapper.kt
   

2. Replace the current permission values with the commented-out code inside the file to enable proper permission checking.

🏗 Project Structure

graph TD;
    app["📱 App Module"]
    home["🏠 Home Module<br>Scan & Connect"]
    control["🎛️ Control Module<br>Connected Device Ops"]
    ble["📡 BLE Module<br>Handles BLE API"]

    app --> home
    app --> control
    home --> ble
    control --> ble

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