The document provides an overview of building iOS apps using Bluetooth Low Energy (BLE), highlighting its advantages like low energy consumption and no need for infrastructure. It discusses the Core Bluetooth API, practical tips for app development, and various hardware products that utilize BLE. Additionally, it covers the definition and usage of GATT attributes, limitations of background operations, and recommendations for app testing without hardware prototypes.

1. Building iOS apps using
"Bluetooth Low Energy"
Shuichi Tsutsumi @shu223
July 25, 2016 Azrieli College, Jerusalem
July 26, 2016 Google Campus - Tel Aviv, Israel
July 27, 2016 SigmaLabs - Tel Aviv, Israel
July 28, 2016 Birzeit University - Palestine

4. Overview
• Basics of BLE
• Practical Tips to build apps using BLE
with Japanse Products

5. Bluetooth Low Energy?

6. Bluetooth Low Energy (BLE)
• Wireless technology
- no network infrastructure required
Wi-FiBLE

7. • Low energy
• NOT compatible with Classic BT
• Uses 2.4 GHz radio frequencies
• Marketed by the Bluetooth SIG
• etc…

8. The most important thing
(for iOS developers)

9. The iOS API ‘Core Bluetooth’
is open for developers
• API for Classic BT is NOT open.
- Requires MFi certification.

10. BLE is almost the ONLY way
to enable iOS apps to communicate
with external hardware
without infrastructure or MFi.

11. konashi moff band sensortag
External HW
• Simple
→ Small, Low cost & Long life
Smart Phone
• High Performance
• Internet Connection
• Easy to program
• etc…
Communicate
with BLE

12. Basics of BLE

14. (Demo)

15. Moff Band Moff App
Sensor Data
BLE Connection
Sensors
- Gyroscope
- Accelerometer
Analyze sensor data
Recognize
- Gesture
- Posture
Play sounds

16. Sensor Data
BLE Connection
How is sensor data sent to the app?

17. Scan
Step 1. Scan
Advertise
: Search for nearby BLE devices
centralManager.scanForPeripheralsWithServices(nil, options: nil)
Peripheral Central

18. Connect
Step 2. Connect
centralManager.connectPeripheral(peripheral, options: nil)

19. Moff Service
xx Service
Button Characteristic
xx Characteristic
Sensor Characteristic
Subscribe
(Request to be notified)
Step 3. Subscribe: Ready to receive data
GATT = Generic Attribute Profile
peripheral.setNotifyValue(true, forCharacteristic: c)

20. Step 4. Notify
Notify
subscribers
Moff Service
Sensor Characteristic
xxxx Characteristic
Update the value
func peripheral(peripheral: CBPeripheral,
didUpdateValueForCharacteristic characteristic: CBCharacteristic,
error: NSError?)
{
print(“Received sensor data!”)
}

21. Hardware Side?
I’m sorry, I don’t know…

22. BLE
Firmware Engineer iOS Engineer

23. Japanese
Hardware Products
I’ve worked on

33. Group conversation system with VoIP
- Detects the human voice
- Cuts out all background noise
→ Can be used even in areas with poor coverage!

34. BLE for BONX

35. IoT for Cars ‘SmartDrive’

36. Printable Open-Source Humanoid “PLEN2”

37. Music for the Deaf
Daito Manabe/Motoi Ishibashi/Teruoka Masaki/Shuichi Tsutsumi x SOUL FAMILY

38. Music for the Deaf
Daito Manabe/Motoi Ishibashi/Teruoka Masaki/Shuichi Tsutsumi x SOUL FAMILY
Commands
Electronic Stimulation DeviceiPhone

40. Practical Tips
to build apps using BLE

41. Defining GATT

42. GATT to send sensor data
Foo Service
Sensor Data Characteristic
UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
Bar Service
xx Characteristic
UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
Properties: Notify
Value: acc x, acc y, acc z, gyro x, gyro y, gyro z (2bytes for each)
xx Characteristic

43. GATT to send button interactions
Foo Service
Button Control Characteristic
UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
Properties: Notify
Value: 0x01 or 0x00
Button interactions
0x01: Pushed
0x00: Released

44. GATT for remote control
Foo Service
Remote Control Characteristic
UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
Properties: Write
Value: Horizontal (-100 ~ 100), Vertical (-100 ~ 100)
values

45. How to define GATT
1. Create UUID for the service & characteristic
2. Define the properties (Read, Notify, Write, etc.)
Peripheral → Central: Notify
Central → Peripheral: Write
3. Define the value format
Usually limited to 20 bytes
$ uuidgen
CEEA31BC-BEAC-4A78-B7ED-FC96B6254D4C

46. Reference:
GATT profiles by Bluetooth SIG

47. Defining background
behaviors

48. Background behaviors on iOS
• Very limited
- Listening to music
- Getting location data
- Downloading data

49. Imagine

50. If BLE didn’t work in the
background…

51. You would have to always keep the app
in the foreground, while snowboarding!

52. You would have to launch the app
whenever you go driving!

53. What functions can be used
in the background in iOS?
• Scanning peripherals
• Connecting with peripherals
• Reading characteristics’ value
• Writing characteristics’ value
• Receiving notifications
Almost all functions can be used
even in the background!

54. Limitations
• Longer intervals for scanning
• Must explicitly specify one or more services to scan
• CBCentralManagerOptionShowPowerAlertKey option is
ignored
Resources
- Core Bluetooth Programming Guide
- Core Bluetooth Framework Reference (also in headers)

55. If the app in the background
is killed by the system…

57. State Preservation and Restoration
The system takes over the BLE tasks
even after the app is killed.
- Preserves the state of the app’s central managers and
continues the BLE tasks on their behalf.
- Relaunches the app into the background and calls the
corresponding callback method.
→ The app can handle BLE events!

58. func peripheral(peripheral: CBPeripheral,
didUpdateValueForCharacteristic characteristic: CBCharacteristic,
error: NSError?)
{
print(“Received the characteristic data!”)
}
• The app is killed by the system
• The user pushes the button on the
peripheral device
• The system receives the notification
• The app is relaunched in the BG and the
delegate method is called.
The app can process the button interaction!

59. How to test
without HW prototypes

60. Did the HW prototypes exist when develop the apps?
Projects HW prototypes existed?
Moff YES
WHILL NO
BONX NO
SmartDrive YES
PLEN2 NO
Music for the Deaf NO

61. Development Kit
Can start development without
creating a circuit ourselves
BLE Module
Display
USB interface
Battery box

62. Horizontal (-100~100) / Vertical (-100~100)
Development Kit App
BLE

64. Emulator App
• Develop another iOS app as the
alternative to the peripheral
device
• Easier for iOS engineers

65. Multi-Function Control
• Single Tap
• Double Tap
• Long Press
• Very Long Press
=

66. App Review

67. Costing too much
MSRP $13,995
Not enough devices when submitting

68. Videos for review
• Show how the app works with the peripheral device
• Not need to be cool!

69. • Shoot with iPhone
• Edit with iMovie

70. Recap
• What is Bluetooth Low Energy?
• Basics of BLE with ‘Moff’.
• Japanese Hardware Products I’ve worked on
• Practical Tips to build apps using BLE
- Defining GATT
- Defining background behaviors
- Testing without HW prototypes
- App Review

71. Thank you!
Shuichi Tsutsumi - iOS Freelancer
• Twitter: @shu223
• GitHub: shu223
• Email: shuichi0526@gmail.com