1. Design Patterns for Connected Specialized Devices
George Roussos
Program manager

2. Agenda What is a Specialized Device?
Connected Specialized Device scenarios
Acquisitions Scenarios
Building a Metro style app for a Connected Specialized Device
Specialized Device design patterns
Choosing the right design pattern for your device
Takeaways

3. What is a Specialized Device??
Devices with
Extensible Built-in Experiences
Printers
Webcam
MB SIM
Specialized
Devices
Portable
Storage
Networked
Other

4. Connected Specialized Device Scenarios
Target Scenarios
An app for a digital video recorder (DVR) that a user can use to remotely schedule recording shows.  
An app for home automation system which controls the lighting in your house and is automatically acquired when it is paired with your PC.
An app that looks for new images on a camera and uploads to local storage or photo service in the cloud.
A phone app that allows user to synchronize calendar, contacts, tasks, and manage media content on phone. The app may also connect to provider service to provide billing information, data rates, and remaining minutes/texts.
A blood pressure monitor app that uploads information to a website so users can track their blood pressure over time and share that information with their family or health care provider.
A payment authorization app for a USB credit-card reader that is automatically acquired when a user attaches the reader to a USB port.

5. Acquisition Scenarios
User’s view
Automatic Acquisition
Physically connected: When the user attaches a USB device to the PC, all device software is automatically acquired, including the Metro style device app that is installed on the Start screen.
-- OR --
Wirelessly connected: When the user joins a UPnP device to a home network, the device is either discovered automatically and directly paired to the PC, or the user goes to the Devices page of PC Settings and clicks on  “Add a device”. All device software is automatically acquired including the Metro style device app that is installed on the Start screen.
Windows Store Download User goes to Windows Store, manually searches for app, and installs it.

6. Building a Metro style app for a Connected Specialized Device

7. Create your own experience
Approach to building a metro style device app for your connected specialized device
1) Re-imagine your device experience as a Metro style device app
Be consistent with the philosophy and principles of Metro style apps
Be inspired by smartphone and tablet apps
Identify appropriate Metro style scenarios for your device
2) Research if there are sufficient Metro style APIs to implement your scenarios
Research the Metro SDK to see if there are sufficient APIs to achieve your scenarios.
Do not plan to port your Desktop app – the Metro style platform is very different. See Primer for current Windows developers
3) Identify the right “design pattern” for your app to communicate with your device

8. Components of a Specialized Device App
Device driver
Device metadata
Metro style app
meta +
app

9. Specialized Device Design Patterns
A Design Pattern represents the programming model a Metro style app can use to communicate with a Specialized Connected Device.
Choose the best Design Pattern for your device based upon the underlying protocol you use to communicate with it.
Design Pattern
Connectivity
Description
API
Networked
Connected over a Wi-Fi network.
Sends and receives data over TCP-IP.
Windows.Networking
Removable Storage
Externally connected over USB.
Can send and receive files from a device.
Windows.Storage
Portable Device
Externally connected over USB Connected over a Wi-Fi or Bluetooth network.
Intelligent device that transfers objects with properties and methods.
Windows Portable Device
WDF Custom Driver Access
Externally connected over USB. Or connected over a Bluetooth network.
Transfers commands and data using device IO control.
Device Access IDeviceIoContrlol

10. Networked Patterns: UPnP
A networked device with UPnP that presents its functionality on a home or work network behind a firewall.
Services presented using XML and information transferred to and from Windows using TCP/IP sockets.
Protocols: UPnP, PnP-X, TCP-IP
Transport: TCP-IP
API: Windows.Networking
Advantages
Disadvantages
Supports ‘Automatically acquired’ scenario
Requires PnP-X support in hardware
Certain networked device classes are automatically paired by Windows. No user interactions are required.
Can’t programmatically pair a networked device from a Metro style app
Supported on ‘Windows RT’
Can’t easily enumerate a networked device before it is paired.

11. Networked Patterns: UPnP
Example
A network connected home automation controller used to program and manage home lighting.
Acquisition Scenarios: Automatic Acquisition, Windows Store Download
Device may be automatically paired depending on Category in Device Metadata
App will be automatically acquired
Device Discovery: Devices.Enumeration + UPnP/SSDP
Device Access: Windows.Networking .
Device
Device metadata
Metro style app +
meta
app

12. Networked Patterns: Private Discovery
Networked device with its own rendezvous mechanism that is Internet-accessible by an online service – such as a DVR programmable over the internet.
Information is transferred to and from Windows using TCP/IP sockets
Protocols: TCP-IP
Transport: TCP-IP
API: Windows.Networking
Advantages
Disadvantages
Easy to implement for existing device
‘Automatic Acquisition’ not supported
Supported on ‘Windows RT’

13. Networked Patterns: Private Discovery
Example
An app for pre-existing digital video recorder (DVR) that a user can use to remotely schedule recording shows.
Acquisition Scenarios: Windows Store Download
Device Discovery: Your own private mechanism – e.g. user logs into account on device
Device Access: Windows.Networking
Device
Metro style app +
app

14. Removable Storage Pattern
Functionality presented as files in a file system
Information transferred to and from Windows with simple file access.
Protocols: USB Mass Storage Class
Transport: USB
API: Windows.Storage
Advantages
Disadvantages
Low cost, standard hardware
Vendor can’t control which apps access device
Supported on ‘Windows RT’
Supports AutoPlay

15. Removable Storage Pattern
Example
Navigation Device:  Device with maps and trails data that can be updated from the cloud by PC and app uploads hike metrics to the cloud
Acquisition Scenarios: Automatic Acquisition, Windows Store Download
Device Discovery: Devices.Enumeration
Device Access: Windows.Storage
Device
Device metadata
Metro style app +
meta
app

16. Portable Device Patterns: MTP
Device content is represented as a virtual storage managed by the device.
Object exchange is handled in Windows by WMP, Windows Explorer, and other 3rd party applications that are written on top of the WPD APIs.
Protocol: Media Transport Protocol (MTP), Picture Transport Protocol (PTP) ver(s) 1.0, 2.0
Transports: USB, Bluetooth, TCP-IP
Restricted Interface
API: Windows Portable Device
Advantages
Disadvantages
Existing MTP devices can immediately use.
Implementing MTP in device firmware from scratch can be costly
Supported on ‘Windows RT’
Protocol is not ideal for devices that primarily stream media to other devices
Supports AutoPlay
C# requires WinRT Component DLL

17. Portable Device Patterns: MTP
Example
A phone app that allows user to synchronize calendar, contacts, and tasks.
Acquisition Scenarios: Automatic Acquisition, Windows Store Download
Device Discovery: Devices.Enumeration
Device Access: Windows Portable Device APIs
Device
Device metadata
Metro style app +
meta
app

18. Portable Device Patterns: WPD Custom Driver
Intelligent device with functionality that fits into a well-defined object model with properties.
Device functionality can be represented as collection of hierarchical storage and/or device services.
Protocols: Needs additional protocol layers beyond what is included in Windows 8.
Restricted Interface
Advantages
Disadvantages
Low cost, standard hardware
Requires a custom driver
Supports AutoPlay
C# requires WinRT Component DLL

19. Portable Device Patterns: WPD Custom Driver
Example
Custom Fitness Device : Bluetooth LE Heart Rate Monitor
Acquisition Scenarios: Automatic Acquisition, Windows Store Download
Device Discovery: Devices.Enumeration
Device Access: Windows Portable Device
Device
Device driver
Device metadata
Metro style app +
meta
app

20. WDF Custom Driver Pattern
A device, such as a USB attached device, that doesn't fit into any of the prior patterns.
A custom device driver is required and a privileged application transfers information to and from the hardware via that device driver by sending IOCTL commands and receiving data..
Protocols: Other
Restricted Interface
API: Device Access: (CreateDeviceAccessInstance(), IDeviceIoControl())
Advantages
Disadvantages
Can meet needs of the broadest range of devices
Costly Requires development and maintenance of a custom 3rd party driver
For devices which already have Windows support, the corresponding custom device drivers are most easily adapted to this pattern
Limited Only vertical solutions are supported, and only a small # of apps can have privileged access to the device
Only designed for custom drivers installed against a specific physical hardware device.
Vendor controls which Metro style apps access their device
Complex This is the most complicated pattern with the most components and moving parts.

21. WDF Custom Driver Pattern
Example
A payment authorization app for a USB credit-card reader that is automatically acquired when a user attaches the reader to a USB port.
Acquisition Scenarios: Automatic Acquisition, Windows Store Download
Device Discovery: Devices.Enumeration
Device Access: CreateDeviceAccessInstance(), IDeviceIoControl
Device
Device driver
Device metadata
Metro style app +
meta
app

22. Choosing design patterns
Choose the design pattern best naturally suited to the protocol and transport your device uses.
See handout for help selecting design patterns based upon technology

23. Resources API Samples Networked Private Discovery <none>
Network UPnP
UPnP
Removable Storage
removable Storage Custom Storage
Portable Device MTP
Portable Device API
WPD Custom Driver
Bluetooth Low Energy Health Profiles sample
Bluetooth Low Energy (LE) Generic Attribute (GATT) Profile Drivers sample
WDF Custom Driver
Custom Device Access
samples

24. Resources
Watch 8 traits of great Metro style apps and Platform for Metro style apps
Specialized Devices Sessions this week
UPnP
Removable Storage
WDF Custom Drivers
Whitepapers
Connected Devices
Whitepaper in progress: Metro style Device App Design Guide for Connected Specialized Devices
PC Internal Devices
Metro style Device App Design Guide for Specialized Devices Internal to the PC

25. Take-aways
Re-imagine what your app should be for the Metro environment - in a fashion that is consistent with the philosophy and principles of Metro style apps.
Be inspired by smartphone and tablet apps
Don’t think about just porting your desktop apps
Evaluate your scenarios to see if there are sufficient Metro APIs to accomplish them.
Choose the right design pattern for your device based upon protocol you use to communicate with it.
See follow-on talks for details about design patterns, samples, and whitepapers

26. Thank you.

27. 11/15/ :10 AM
© 2011 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2009 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

28. 11/15/ :10 AM
© 2011 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2009 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.