Design Considerations

Devices 

Too often development teams start with the technology, rather than the requirements or learning objectives. The learning outcome should always be the main focus, but familiarity with the capabilities of the different types of handheld devices that learners use may open new doors, or it may even require taking a step back.

When thinking about mobile device categories, remember that the mobile device is more than just a phone. Basic mobile phones are limited for mLearning. The following list provides a logical way to categorize mobile devices that have the most potential for mobile learning. 

Feature Phones Usually non-multitouch, but have advanced features (accelerometer, high MP camera, and Bluetooth) and good web browser support.
SmartphonesSystem-On-Chip (SoC), full browser / HTML support, Wi-Fi, 3G/4G, music player, GPS, video-capable, Bluetooth, touch support, accelerometer, 3D video acceleration, etc.
Non-phone DevicesWi-Fi support, browser, other features, etc. iPod, iPad, e-Book readers, etc. This could also include tablets, PDAs (personal digital assistants), handheld game consoles or portable media players.

Mobile device categories will continue to evolve both from a function and feature perspective and from vendor marketing messages. The main concern  and question for mobile learning developers is: what devices and/or features are supported for the intended learners?

The majority of mobile subscribers in the United Stated as of May 2012 own a smartphone (according to the latest numbers from Nielsen). The research firm found that 50.4% of all U.S. mobile subscribers owned smartphones in March, up from 47.8% in December 2011. Consumers purchasing new phones picked smartphones more often than featured phones, with Apple called the top manufacturer and Android as the top platform. During the first quarter of 2012, 48% of smartphone owners had an Android-powered device, while 32% of devices ran iOS and 11.6% were on the BlackBerry platform. The dated Windows Mobile OS owned a 4.1% share of the market, ahead of Windows Phone at 1.7%. 

Features

Devices are equipped with various features that could be used to enhance learning. Which features do your learners have? Please access the glossary if you need more details about any of these features.



  • Accelerometer
  • Audio recorder
  • Audio and video player
  • Battery life
  • Browser
  • CAC support
  • Camera (still or motion)
  • Compass
  • GPS
  • Gyroscope
  • Keyboard
  • Memory
  • Microphone
  • Processor
 
  •  Screen
    • Color
    • Resolution
    • Size
    • Stylus
    • Touch
  • Scanner
  • Security (e.g. biometrics)
  • Size
  • Software (E-book reader, etc.)
  • Storage
  • Text messaging
  • Video
  • Wi-Fi Connectivity

Tablets

Tablets
When defining mobile devices, we generally refer to devices which:
  • Turn on instantly (don’t require boot-up)
  • Are carried in a pocket or purse most all the time and are gaining ubiquity
  • Have sufficient power to last one day
  • Have input and output capabilities and a processor
Tablets are not normally carried at all times, but their use is growing rapidly in education and training. While iPad is the most well known tablet on the market, several others are now available on other platforms and in various screen sizes:
  • Excite Tablet (Google)
  • Galazy Tab (Samsung)
  • Iconia (Acer)
  • Kindle Fire (Amazon)
  • Nexus 7 (Google)
  • Nook (Barnes & Noble)
  • Playbook (BlackBerry)
  • Streak (Dell)
  • ThinkPad (Lenovo)
  • Thrive (Toshiba)
  • Touchpad (HP)
  • Transformer Pad (Asus)
  • Xoom (Motorola)
Some of the tablets listed above have actually been discontinued and are no longer available to purchase (e.g. HP Touchpad) while others are still trying to break into the lower-cost market to try and compete with iPad. Other than differences in screen sizes, learning content for tablets require development very similar to mobile phone development as they share many of the same powerful hardware capabilities. 

Display

Screen

screen displays comparison
A mobile device has a small screen when compared to a desktop screen. In the desktop world, the sizes range 13, 15, 17, 19, and 21-inch screen sizes (diagonally). In mobile development the screen size range is usually 1.5 to 3.7 inches for mobile phone devices.



Screen Resolution

Various screen sizes
In the desktop world the most common screen resolution is 1024x768 pixels.  How many pixels (width x height) are available on your target audience's device(s)? This is important to consider when creating graphics for mobile screens. 

The most widely available screen resolution is 240x320 pixels. Some devices might have a resolution of 128x128 pixels, and some 800x600. Up until 2010 most mobile devices fell into four basic groups:
  1. Low-end devices: 128x160 or 128x128 pixels
  2. Mid-end devices (group #1): 176x220 or 176x208 pixels
  3. Mid-end devices (group #2) and high-end devices: 240x320 pixels
  4. Touch-enabled high-end devices and smartphones: 240x480, 320x480, 360x480, 480x800, 480x854, or 640x960 pixels 
When Apple introduced the iPhone 4 in 2010 it boasted a new 960x640 resolution, and an 800:1 contrast ratio. The third generation of iPad revealed support for 2048 x 1536 resolution with its new retina display.  
  • iPhone: 320x480 | 3.5 in | 164ppi
  • Palm Pre | 320x480 | 3.1 in 186ppi
  • Palm Pixie | 320x400 | 2.63 in | 194ppi
  • T-Mobile G1 | 320x480 | 3.2 in | 180ppi
  • 
MyTouch 3G | 320x480 | 3.2 in | 180ppi
  • 
HTC Hero | 320x480 | 3.2 in | 180ppi
The next set of Android phones featured much higher PPI only to be bested by Nokia's next generation of smartphones and finally the iPhone 4.

  • Motorola Droid | 480x854 | 3.7 in | 264ppi
  • Nexus One | 480x800 | 3.7 in | 252ppi
  • 
HTC Desire | 480x800 | 3.7 in | 252ppi
  • Nokia N97 | 360x640 | 3.2 in | 229ppi
  • Nokia N900 | 800x480 | 3.5 in | 266ppi
  • Apple iPhone 4 | 960x640 | 3.5 in | 326ppi
As you can see, the mobile design landscape continues to evolve as these new technological advances in screen displays presents new challenges. The above information was provided by Luke Wroblewski as his site has an excellent list of resources on this topic here: http://www.lukew.com/ff/entry.asp?1142

Aspect Ratio

This is the ratio between the longer and shorter dimensions of a display.
  • Horizontal (landscape) devices have displays that are wider than they are tall
  • Vertical (portrait) devices have displays that are taller than they are wide
  • Square screens have the same width and height
Mobile content should be developed with an awareness of the rotation capability provided by accelerometers and should offer a consistent experience in any screen orientation.

Accessibility

Input Methods

screen showing gesture
A mobile device may support only one input method or it can support many options. Possibilities include:
  • Alphanumeric keypad
  • Screen keypad (Touch)
  • Multi-touch events
  • External keypad
  • Handwriting recognition (gesture search)
  • Voice recognition

Handwriting Recognition (Gesture Search)

Navigation

Every mobile browser uses one or many of these modes of navigation:
  • Focus navigation (e.g., using scroll wheel)
  • Cursor navigation (e.g., ball or scroll wheel)
  • Touch navigation
  • Multi-touch navigation (e.g., double tap)

Browsing

image of mobile web browser
There are several different approaches to opening more than one browser window at the same time. Here are some examples of the different behaviors on mobile browsers:
  • Only one page support
  • Multiple windows
  • Windows stacks
  • Tab navigation


iPhone Browsing (multiple windows)

Connectivity & Bandwidth

For most users, bandwidth is becoming less and less of an issue with the availability of 3G and 4G networks. However, connectivity will always be an important consideration for mobile development strategy. Issues to consider when addressing device connectivity and bandwidth:
  • Data Plan Cost / Usage
    • The days of unlimited data plans are phasing out. Most carriers now have placed 2-3GB caps on data usage. 
    • If you require your users to download sizeable apps or large amounts of content, then you may have to consider leveraging wifi network capabilities to offset the data usage costs that would be incurred by using your data plan.
  • Image Compression: Files must be optimized for quicker load times
  • Mobile Web Browser Transcoding: What is transcoding? A transcoder is a proxy that intercepts web content and reformats and compresses it with built-in or user-installed microbrowsers (e.g. Opera mini)
    • Sometimes cause problems and degrades content / breaks device detection
    • Alleviated by adding the Cache-Control: no-transform header to all your HTTP responses
    • Also by using mobile-specific MIME types and DTDs (XHTML Mobile Profile)
    • Setting up a hostname / domain with a pattern such as m.*, wap.*, or *.mobi will usually also help
    • Caching lowers download times and costs but can also cause unwanted behaviors when creating web content for mobile devices
  • Offline & Data Storage
    • Native applications offer several options for storing your data offline, but each OS provides a unique way to do this. If no connectivity is available, you should provide minimal user experience for an offline mode, and not create a constant dependency on a connected mode. Otherwise, you could quickly lose from your users.
    • If developing for the mobile web, HTML5 provides a means for persistent local storage of data (for times of little or no connectivity)
      • Similar to cookie concept, but not auto transmitted back to the server
      • The data remains local as keyed name / value pairs to be stored within the browser
      • Limited to 5MB

Performance

System on a Chip graphic
Here are some of the top considerations when thinking in terms of performance. These can vary significantly from one device to another.
  • Battery life
  • Memory and storage
  • Processor (SoC – System on a Chip)

Advanced Capabilities

Gyroscope and advanced chips
Smartphone competition has increased the number of sensors and other advanced capabilities made available to consumers. The iPhone 4 was the first to offer a built-in, 3-axis gyroscope. Advanced capabilities such as this can offer an enhanced experience if it is supported on the device of your target audience.
 

Caveat

All mobile devices are not created equal. Consider the following issues when deciding on a mobile development and design strategy:
  • An emulator is not always consistent with the actual device
  • Adobe has discontinued support of the mobile version of their Flash Player
  • Poor / inconsistent support for pop up windows and framesets
  • Limited video support (Varying formats supported)

Video Formats

Examples of the preferred formats supported on some mobile device platforms are identified below. Using video will likely require some form of device detection for delivering mobile web content. The most common video formats supported across most devices are MP4 and 3GP. However, video content packaged with a native mobile app may require a specific encoding type for each platform and playback may or may not be supported.
  • RIM BBOS: MP4, 3GP
  • Apple iOS: M4V, MP4
  • Microsoft Win Mob/Win Phone7: WMV, 3GP
  • Google Android: MP4, SWF
  • Nokia Symbian: MP4, WMV
  • PalmOS/WebOS: MP4/H263
For the best results of supporting video across multiple platforms, take a look at the Universal Video Encoding for MP4 article here: http://blog.zencoder.com/2010/09/30/how-to-encode-video-for-mobile-use/

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