Building Apps for Wearable and IoT devices using BLE Prachanda Muni Bajracharya • 01.15.2025

Bluetooth Low Energy (BLE) Overview ● Low Power Consumption ○ Bluetooth Low Energy is a wireless communication technology designed for low-power devices. ● Short Range Connectivity ● Secure Communication ● Widely Adopted ● Different from Bluetooth Classic.

BLE Core Concepts ● Central and Peripheral ○ Central: The device that initiates and maintains the connection (e.g., smartphone). ○ Peripheral: The device that advertises its availability (e.g., wearable). ● Services and Characteristics ○ Services: A collection of related data (e.g., heart rate service). ○ Characteristics: Specific pieces of data within a service (e.g., heart rate value). ● Advertising ○ Peripheral devices broadcast information to nearby devices. ● GATT (Generic Attribute Profile) ○ Defines how data is transferred between devices.

BLE Communication ● Advertising: Peripheral sends advertising packets. ● Scanning: Central scans for available peripherals. ● Connection: Central connects to a selected peripheral. ● Data Exchange: Data is read or written via GATT services and characteristics.

BLE Communication

Heart Rate Example This is the Heart Rate Profile specified by Bluetooth SIG (Bluetooth Special Interest Group): ● Heart Rate [Service] UUID: 0x180D Primary Service ● Heart Rate Measurement [Characteristic] UUID: 0x2A37 Properties: Notify Value: 70 bpm ● Body Sensor Location [Characteristic] UUID: 0x2A38 Properties: Read Value: Finger

BLE Architecture

Operations ● Requests (Central to Peripheral) ● Responses (Peripheral to Central) ● Commands (Central to Peripheral) ● Notifications (Peripheral to Central) ● Indications (Peripheral to Central) ● Confirmations (Central to Peripheral)

Tools and Frameworks ● Mobile Development ○ iOS: Core Bluetooth Framework. ○ Android: Android Bluetooth Low Energy API. ○ Flutter: FlutterBlue, reactive_ble. ○ React Native: react-native-ble-plx, react-native-ble-manager ● Testing Tools ○ nRF Connect: A BLE development and debugging tool. ○ BLE scanners: Analyze BLE advertising packets.

Challenges ● Connectivity Issues ● Platform-Specific Behavior ● Handling Multiple Devices ● Data Throughput and Latency ● Debugging Challenges ● GATT Complexity ● Data Syncing ● Power Consumption ● Device Compatibility ● Security Concerns ● Handling Firmware Updates

Usage ● Wearable Technology ● Healthcare Devices ● Smart Home System ● Asset Tracking ● Targeted ads

Thank You !!!