Handling BLE & Bluetooth in Mobile Apps development
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Bluetooth and Bluetooth Low Energy (BLE) allow devices to communicate wirelessly over short distances. Both operate in the 2.4GHz frequency band but BLE is designed for lower power consumption and longer battery life. On mobile devices, Core Bluetooth framework (iOS) and BluetoothAdapter (Android) allow connecting to and communicating with BLE devices. Services and characteristics define the data structure that can be read from and written to BLE devices. Background processing differs between iOS which has limited support, and Android which uses services for long-running asynchronous tasks.
Handling BLE & Bluetooth in Mobile Apps development
- 1. S Handling BLE & Bluetooth in mobile devices SVV Satyanarayana
- 3. What is Bluetooth S Bluetooth is short range wire-less communication technology that allows devices to transmit & receive data without connection, to short distance S Originally designed for continuous & streaming data applications. S Wireless headsets, keyboards, mouse, printers are few examples that use bluetooth
- 4. S BLE
- 5. What is BLE S Acronym: Bluetooth Low Energy S As name suggests, its for low power consumption & devices run on small battery for longer duration S Connection between devices is not continuous. BLE remains in sleep mode except when connection is initiated. S Widely used for M2M communication
- 6. Common in Bluetooth & BLE S Both operate in same frequency 2.4GHz ISM band and similar RF power output S Both operate with same pairing technology, authentication & encryption S Both operate in master-slave model. First pairing happens and later data transmission happen
- 7. Difference between Bluetooth & BLE Factors Bluetooth BLE Amount of Data More data Less data Battery life Low High Cost High Low Communication Uni directional Bi-directional Data transfer rate 2-3 Mbps 200 kbps Latency < 6s Time for sending data Typically 100ms Typically 3ms Power consumption 1 (as reference) 1% to 50% of Bluetooth Products suited for Continuous data transfer such as streaming video/audio, IOT etc Products that involve in-frequent data transfers and need to operate on low power consumption Range Roughly 100m Roughly 100m
- 8. S Comparison of Bluetooth & BLE in iOS & Android
- 9. Usage of Bluetooth Factors iOS Android Framework External Accessory framework Bluetooth Adapter Connect from App Not possible Possible Communicatio n in background Possible Possible Automatic re- connection (if lost) Not possible Possible
- 10. Usage of BLE Factors iOS Android Framework Core Bluetooth framework Bluetooth Adapter Connect from App Possible Possible Permissions from User Required Required Read & Write Possible Possible
- 11. S BLE Access from IOS & Android Devices
- 12. S Basics
- 13. Profiles – Connect & Communicate S GAP & GATT are 2 profiles that are used to establish connection and communicate with devices S Generic Access Profile (GAP): For scanning & connecting to devices S Generic Attribute Profile (GATT): Access attributes from devices through services & characteristics
- 14. GAP - Roles S Broadcasting: Not necessary to connect to one another to transfer data S Broadcaster: A device that broadcasts data to all S Observer: A device that listens for data being sent by broadcaster Continued…
- 15. GAP - Roles S Connecting: Must handshake to communicate with each other (most commonly used role) S Peripheral: A device that advertises its presence. They are small, usually low powered as they have to send beacons periodically. S Central: A device that initiates connection with peripheral.
- 16. GATT - Profile S GATT Client: Sends request to GATT server. Client can read and/or write attributes found in the server S GATT Server: Provides the stored attributes/values.
- 17. Services & Characteristics S GATT transactions are based on high-level objects called Services & Characteristics S Services: Collection of data and associated behaviors to perform particular function or handle a feature. A service can have one or more characteristics. UUID represents a service. S Characteristics: Single data point/value used in a service. It includes configuration info about accessing its value. Its also represented by UUID
- 19. BLE setup S Scan devices that advertise specific services S Initiate connection & Connect to device S Discover services S Discover characteristics S Register for notifications S Read & Write
- 21. Access Bluetooth in iOS S Accessing Bluetooth is done with the help of ‘External Accessory’ framework S Enable background mode in app capabilities so that app can receive the the data from Bluetooth device. S Note: Bluetooth device must be paired from iOS System Bluetooth settings, where as with BLE we are able to add the devices from the app side.
- 22. S Handling BLE in iOS
- 23. iOS Implementation S Communication with BLE devices in iOS is handled using ‘Core Bluetooth’ framework S Use CBCentralManager object to scan and connect to devices. S CBPeripheral represents the device to which its connected, use its delegate to discover services & characteristics S Read, Write data & Notify using above object and its delegates.
- 24. S Handling Bluetooth & BLE in Android
- 25. Android Implementation S BluetoothAdapter provides BLE integration functionality S Same has ability to handle Bluetooth & BLE in Android devices S Use above to scan and connect to BLE device S BluetoothDevice object represents the device to which its connected S BluetoothGatt instance represents the service & BluetoothGattCharacteristic represents the characteristic of the device. S Use above objects for read, write data & notify observers
- 26. S Additional info: Background Functionality in iOS & Android
- 27. Background mode in iOS S iOS Apps have limited functionality to perform in background. S BG modes supported: Play audio, Receive location updates, Perform finite-length tasks, BG fetch, VOIP tasks, News stand, BLE accessory functionality, remote notifications. S Background app fetch mode provides the ability to fetch data from server, but posting more data frequently to server might have restriction from Apple
- 28. Background mode in Android S A service is an application component that can perform long-running operations in background S No UI needed for running service. Service will be initiated along with first launch of the app and it runs asynchronously. S Best suited for data sync in background received from BLE devices