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Android Gadgets,Bluetooth Low Energy,
and the
Gadgets: From Wired...
USB peripherals are no good
● No brand-to-brand standard protocols● Bad hardware, yucky APIs● No consistent form factor● Cords are the worst
...To Wireless
● AKA: The Reason Your Phone’s Battery Lasts For 2 Hours
● High throughput data streaming
● Wireless audio, video, etc
● Many protocols
Bluetooth Classic
● AKA: Bluetooth Low Energy
● ...Lower energy
● Low throughput / periodic data transfer
● Sensors, beacons, Internet of Things, etc
● One general protocol
Bluetooth Smart™
The BLE Stack
Physical (Single/Dual)
Link Layer
L2CAP
GATT
The GATT Protocol
Characteristic
Attribute
Attribute
Heart Rate
BPM
Transmit Rate
The GATT Protocol
Service
Characteristic
Attribute
Attribute
Characteristic
Heart Rate Monitoring
Heart Rate
Location on Body
Peripheral
Service
Attribute
Attribute
Characteristic
Service
The GATT Protocol
Cardiac Health Device
Heart Rate
Blood Pressure
Characteristic
The GATT Protocol
Peripheral
Service
Characteristic
Characteristic
Service
Server Client
Respond/Push
Read/Write/SubAttributeAttribute
Scan21
Advertise
3Connect and Subscribe
Push New Data4
Slave Master
Connecting
● Operates on 2.4 MHz band ○ Same as WiFi, Bluetooth Classic
● No protocol limit on number of connections○ Only limited by hardware / software stack
Numbers
Examples
How do I make cool things with BLE?
Your starter kit for the Internet of Things!
Hardware
Look: No Hands!
Sensor Data
BLE
Android Device
Master Module
relayrCloud
Real-World Applications
CODE (finally)!
InsulinAngel Code and BLE best practices
Demo: InsulinAngel
● Issues reconnecting to device○ Solution: reset the stack if a problem
● Different device-to-device quality○ Solution: thorough testing / set user expectations
BLE is… Temperamental
● Data transfer is encrypted / jumps channels
● Initial connection packets are UNENCRYPTED
● Take great care with sensitive data
Security
Contact
Peter Dwersteg
@relayr_cloud
GATT Protocol: http://bit.ly/1yW8Bn3
Security Concerns: http://bitly.com/1sycM4G
