how to use bluetooth® smart to control your embedded device with a mobile device
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Bluetooth SIGMember
Bluetooth SIGMember
Using Bluetooth® Smart to Control Embedded Systems
with a Mobile Device
[email protected]+44-2392-232392
Bluetooth SIGMember
Any device can send state/status
You forgot to Floss your teeth yesterday. Today you need to brush your
teeth for more time.
You didn’t complete your 10k steps goal yesterday. Spend more time at the
gym today.
I am behind the sofa cushion. Find me here..!!
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IOT: Base elements
Flow
On/Off
Light
PressureOpen/ Closed
Temperature (Hot/Cold)
Location
Bluetooth SIGMemberHow do we connect every device
to the internet?
Portability / mobility
Battery Life
Expensive + Battery life
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A gateway to the internet
Gateway
Bluetooth SIGMemberWhat does a smart phone offer
as a gateway?
Standard Wi-Fi Bluetooth NFC
Mobile can be master? Yes Yes Yes
End Device Broadcast Yes Yes No
Scanning No Yes No
Battery Life of End Devices /Slaves Few hours
[3.0] Few Hours
[LE] Few YearYears
Bandwidth provided Video State [LE] Voice [3.0] State
Asynchronous Data transfer by End Devices Not Supported Supported Not
Supported
Range of connection 75-120 m 10 – 100 m 10cm
Relative Cost of Implementation Low Lower Lowest
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What is BLE?
• Bluetooth low energy technology is an evolution in technology that enables new applications in wireless devices that are able to last months or even years off a small, button-cell battery
• Ultra-low power consumption• Low cost• Multi-vendor
interoperability• Enhanced range
relative to classic Bluetooth
* Graphic courtesy of Bluetooth® SIG
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BLE technical specifications
• Uses FHSS spread Spectrum technology to overcome interference• Operates at 2.4 GHz ISM band which is accepted worldwide• Very Low Duty Cycle:
– Radio spends very little time in TX/Rx mode– Radio shuts down very fast
• Asynchronous Connectionless MAC– Small Packets [MTU = 20 bytes]– Uses only 3 channels for advertising hence less time to establish link– Fast Connection and teardown in < 6ms *Graphic Courtesy of iebmedia.com
Bluetooth SIGMemberWhat can a Bluetooth Smart
connection do for you?
• Connect your embedded device to a smartphone:- monitor & collect data- control operation and adjust settings- field service interfaces- over-the-air software updates- and more …all touch-free & without opening a cabinet!
• Easy to change the HMI controls and gauges – it’s all software
• Secure: Control and limit access
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Product objectives
• Time to Launch to market = 1 month / 3 months / 6 months • Customer never needs to replace battery• Over the AIR update: no need to plug any wires
Marketing Objectives
• Lower Bill of Materials• Low NRE / Engineering Costs
Operations Objectives
• Sell the product worldwideSales Objectives
• Where do I start?Engineer objectives
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• Range and Data throughput• Battery Life and Sleep current• Over the AIR update
BLE Radio Objectives
• Design the Radio or go with a Module?• Application Firmware: Integrate with BLE stack or Separate
Applications Processor?
Application Objectives
• GATT Model• GATT Specification: Profiles, Characteristics, Services• Custom GATT profiles
Determine Data Flow Needs
• Testing product using Generic Applications• Generic Apps on PC / Mobile • Cross Platform mobile app development
Mobile App Objectives and Testing Product
• Regulatory Certification• Bluetooth SIG Qualification• Benefits of pre-certified and pre-qualified modules Go to Market
5-step checklist to start your design
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1: BLE radio objectives
BLE Range: up to 100 meters• 2.4 GHz is attenuated heavily by human body• Placing radio in metal enclosure or right on top of coin cell
battery will cause multipath/ reflections and packet loss
BLE Data throughput: Radio data : 1Mbps, BLE spec: .27Mbps • It is designed for sending small chunks of data or ‘state’ of
the device• Given the low duty cycle, it not optimized for large file transfer
or streaming
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1. BLE radio objectives (cont.)
Battery Life:Assuming a transaction of 3ms, Tx/Rx avg. current consumption: 17mA Std. CR2032 coin cell battery: ~220mAhCalculations: = 220mAh/17mA /.003s = ~ 13 hours = ~15.5 mil. Packet transactions
Important contributors to extend battery life• Sleep current modes: BLE radio are in Sleep mode for almost all the times
a. Sleep with OSC onb. Sleep with Timer Onc. Sleep with External Interrupts On \ Deep sleep
• Adding DC-DC converter helps reduce power consumption in TX/RX mode
No. of End Device packet transmission per minute
Estimated Battery Life on CR 2032
Estimated Battery Life on std. AA [~1Ah]
1 24 year 100 years
12 2 years 10 years
60 0.5 year 2.5 year
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OTA (Over the Air Update)- Supported by most radio vendors- While choosing Flash size
* double of the firmware size * future addition of features
1. BLE radio objectives (cont.)
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2: Embedded application objectives
Design your own radio or go with a module?
• RF expertise• Time consuming: PCB Design• Upfront Engineering cost • Easy to make changes • Module: Fast prototype and low annual
volumes where time to market is important
• DIY: Post proto and high volume production
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2: Source a BLE radio
Application and Stack on single BLE Chip
Separate Applications and BLE Processor
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3: Determine data flow needs
The BLE Stack: GATT Model• Based on attributes• Simple to use• Key terms:• Central / peripheral• GATT specifications
– Services– Characteristic– Profiles Physical Layer
[PHY]
Link Layer [LL]L2CAP
Host Controller Interface [HCI]
ATTGATTUser Applications
SMP
GAP
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GATT specificationsService: Human Readable specification of set of characteristics, eg. Glucose Monitoring, Blood Pressure Monitoring
Characteristics: Defined attribute types that contain a single logical value. These are machine readable only, eg. Battery voltage
Profiles: Define how services can be used to enable an application or use case. Profiles enable interoperability among products made by different manufacturers, eg. Healthcare, Proximity Sensing
3: Determine data flow needs (cont.)
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• Bluetooth SIG has adopted numerous profiles to make it easier for developers. Can be found at Bluetooth developer site
• But what if the existing profiles don’t work for you? You can create custom profiles
• How? Push / Pull / Broadcast– Product sends to smartphone (Push)– Smartphone Connects/Reads/Writes (Pull)– Product broadcasts data even when not connected [indicators /
notifications]
• Security : – Button pairing– Pin code– Unique key pairing
3: Determine data flow needs (cont.)
Bluetooth SIGMember4: Mobile app objectives & product
testConcurrent Code Development
Embedded code
Mobile app code
iOS & Android mobile; PC; etc.
App. c Main. c
Hardware prototype
Your embedded device
To market
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Embedded Device to Mobile DeviceEmbedded Device to PC
Image courtesy : TI and Punchthroughdesign.com
Test product using a generic interface
4: Mobile app objectives & product test (cont.)
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Packet sniffer
4: Mobile app objectives & product test (cont.)
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Packet sniffers
* Image courtesy of Frontline
4: Mobile app objectives & product test (cont.)
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Cross platform mobile apps
4: Mobile app objectives & product test (cont.)
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5: Go to market
Regulatory Certifications :
• Verification that the operation of a device meets set limits or performance expectations within a given country or geographical region
Americas
Canada
European Union
China
Japan
Australia
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5: Go to market (cont.)
Bluetooth SIG qualification Process:• all Bluetooth products must be qualified to use the Bluetooth trademark/logo• fully qualified product is listed as End Product Listing (EPL)
* Graphic courtesy of Bluetooth® SIG
Bluetooth SIGMember 5: Go to Market (cont.)
Benefits of using a pre-certified module
Discrete Design Pre-Certified / Pre-Qualified Modules
Fees for Regulatory Tests Approvals [FCC/ETSI/IC]
25000 9000
Software Dev. Costs for Test Firmware
20000 1000
Additional Countries 20000 (approximate)
1000
Bluetooth Qualification * (Associate member)
4000 4000 [only EPL]
Total Costs 70,000 15,000
* Bluetooth SIG Fees are based on membership levels Adopter: $8k / Associate : $4k / Innovation Incentive Program (companies with annual revenue <$1 m USD): $2.5k USD (2 products max.)
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Summary: How to get started
• Project objectives influence the product design & development process• Regulatory compliance can significantly delay product launch & raise
costs• Pre-certified module can reduce time to market, simplify prototyping,
streamline compliance & eliminate need for RF infrastructure• For complex applications, use the co-processor approach for proof of
concept and initial prototypes• For mobile development, use of generic cross-platform application
development compilers• Perform regulatory compliance tests and obtain Bluetooth EPL listing to
use the Bluetooth logo
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A word about Anaren’s BLE solution
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Bluetooth Smart Development Kit
• Works with Atmosphere web-based development platform– Simultaneously creates & compiles embedded code for
demo board and code for mobile app creation– Examples based around the AIR-for-WICED multi-
sensor development board with exposed GPIOs, UART, SPI and I2C connections
• Includes:• Unlimited access to the online Atmosphere
collaborative development platform • Multi-sensor dev board• USB cable (probably Type A to Micro B)• 2 single-row header pins• Quick Start Guide• Regulatory Guide Part #: A20737x-MSDK1
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Atmosphere online development platform
• Enables developer to simultaneously generate embedded code & mobile app code in one, environment
• Public site & community at: https://atmosphere.anaren.com
• Users accesses tool via freeaccount registration (agrees to T&C & use of AIR for WICED modules)
• Downloads & installs on PC/Mac/Linux device
• Mobile app to be available on App Store & Play Store
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Where you can learn more
References :• https://atmosphere.anaren.com• http://anaren.com/airforwiced• http://developer.bluetooth.org/• http://en.wikipedia.org/wiki/Bluetooth_low_energy• https://mentor.ieee.org/802.18/dcn/13/18-13-0049-00-0000-f
cc-modular-transmitter-guidance.pdf