BLE Explorer

This is a refresher exploration of BLE utilizing patterns I have used in the past, but adding new types for managing received data such as Kotlin Flows. I have been tinkering with this on and off for a few years. This is currently a work-in-progress. I have been updating the codebase as libraries have been updated.

NOTE This is definitely not a hardened app.

NOTE This is not to demonstrate best practices of UI/UX design nor a model app for Jetpack Compose usage; just enough to demonstrate the BLE functionality.

NOTE There is no road map for this project.

As of right now it:

• Scans for devices using BleScan
• GATT Status Codes
  • Known GATT Status Codes
• Advertisements
  • Advertising Data Types
    • Flags
    • Manufacturer Data
• Connects to devices using BleConnection
  • Supports MTU negotiation
  • Handles connection state changes
  • Handles disconnections
  • Handles connection timeouts
  • Discovers services and characteristics
    • Service
    • Characteristic
    • Descriptor
    • BLE Attributes
  • BLE Requests
    • Manages a queue of requests to the device, processing them one at a time
    • Synchronous blocking requests see
      • BleConnection.readCharacteristic
      • BleConnection.readDescriptor
      • BleConnection.writeCharacteristic
      • BleConnection.writeDescriptor
    • Asynchronous requests processed via callbacks. See BleConnection.submitBleRequest
    • BleRequest
    • BleRequestResult
    • Reads characteristics
      • CharacteristicReadRequest
    • Writes characteristics
      • CharacteristicWriteRequest
      • Supports chunking for large writes
      • Supports resending on failure up to a configurable max retry count
    • Reads descriptors
      • DescriptorReadRequest
    • Writes descriptors
      • DescriptorWriteRequest
      • Supports chunking for large writes
      • Supports resending on failure up to a configurable max retry count
    • Subscribes to notifications
      • EnableNotifyCharacteristicRequest
• BLE Device representation (BleDevice) - the Central's representation of a Peripheral; this is the place to start exploring as any interaction with a Peripheral should be done through a subclass of BleDevice.
• BLE Peripheral support - allows Android device to act as a BLE Peripheral (GATT Server)
  • BaseBlePeripheral - Abstract base class for creating a BLE Peripheral
    • Handles BLE advertising with customizable settings
    • Manages GATT server setup and lifecycle
    • Supports multiple client connections
    • Handles characteristic read/write requests
    • Supports notifications/indications to subscribed clients
    • Performs MTU negotiation
    • Permission checking
  • PeripheralService - Service definition for peripherals
  • PeripheralCharacteristic - Characteristic with managed state
  • PeripheralLog - Tracks peripheral operations for debugging
  • SendDataRequest - Handles chunking for large notification payloads
• Provides some common BLE Attributes (see attributes)
• A test app UI to interact with devices that demonstrates the following functionality:
  • Scanning
  • Scan results
  • Connecting to a device
  • Connection state changes
  • MTU changes
  • Services discovered
  • Sample Communication between a SampleBlePeripheral (extends BaseBlePeripheral) via the Peripheral screen and a SampleBleDevice (extends BleDevice) via the Central screen. This demonstrates:
    • Scanning for a specific device type using a service UUID filter
    • Connection
    • Read Characteristics
    • Write Characteristics
    • Notifications using the SamplePeripheralProtocol
    • Disconnecting

ANOTHER NOTE Development is slow moving here, not everything is perfect