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Get a Grip on Wireless... Selecting the Right Device - Part One
Volume 1 Issue 2 -- This special contribution is the second installment in a series of discussions centered on the wireless
application development process. Interested recipients can
subscribe at http://www.outr.net/news.htm and receive the articles via the outr.net newsletter.
The article was first published April 27, 2001.
The world is going wireless crazy.
If you believe some
companies and analysts we’ll all be running our lives and
businesses through wireless devices and applications in the not too
distant future. Much of it is hype. Yet it’s all grounded in some
degree of reality.
Differentiating between the two can be difficult. But keeping focused on your wireless goals, applying
sound business principles and avoiding potential development pitfalls should keep your wireless
application on the right track - and in the reality column.
Which brings us to the topic of selecting the appropriate wireless device, the first of our “Top Ten”
Pitfalls. It’s one of the most crucial choices you’ll make, particularly because it comes at the front end
of the wireless application development process.
To a large extent, the capabilities of your wireless application are determined by the features and
functions of the wireless device. Is there an absolute right or wrong device for your application?
Probably not, but keep in mind that some devices will be better than others. Making the best choice
possible should be your goal. And in many instances, the best choice will be multiple devices.
A good place to start in device selection is a clear statement of the wireless problem you’re trying to
solve. Then consider existing constraints that could limit your wireless project or device choice.
Examples include network airtime “deals” or a user who can’t live without a particular PDA. Equally
important is knowing the range of devices available in the market place - both today and in the future.
That said, the following discussion centers on a number of device selection/evaluation criteria. They
may not all apply to your wireless application and development process but consider them a convenient
check and balance against what you may have discovered already.
Form Factor
Sometimes it’s best to begin with the obvious. Form factor issues are primary considerations in any
device selection and something you’re not likely to overlook. But just like a great magic trick, there is
often more to wireless devices than what meets the eye.
Screens are a good example. For instance, you may have a minimum display size in mind for your
application. Or maybe you know a touch screen works best for the level of navigation required. But have
you considered how the application will actually look on the screen or whether backlighting is
important? Would you know if weather conditions could affect the display?
Display technology varies from device to device as does screen resolution. Having more screen real
estate doesn’t necessarily ensure higher resolution or better-looking graphics. Sometimes higher screen
resolution results in smaller fonts, which affect readability. And just because a screen is readable indoors
doesn’t guarantee similar results outdoors where screen glare is to be expected.
Backlighting is just as important if dimly lit environments or nighttime use factor into the application
equation. Even environmental conditions, like heat from the sun or a cold winter blast can affect screen
appearance so it’s good to know if the device has adjustable contrast. Then again, are you willing to
subject your users to the wide fluctuations some screens are prone to?
Device size and keyboards are other obvious form factor considerations that deserve extra attention.
While everyone seems to want the smallest, lightest and most compact device possible, there are times
when these characteristics present application impediments. Could your preferred device be too small or
the keyboard too compact for the hands of your users?
Form factor issues may appear simple but they’re not always obvious. If you’re going to make a wireless
device an integral part of someone’s job be sure you look at the choices and options from their
perspective. Gloss over some critical factors and - presto changeo - you may just turn a successful
application into a dog.
Batteries
Everyone knows wireless devices can’t run without them but odds are you haven’t given batteries more
than a passing thought in your device selection process. Surprisingly, batteries can be make-or-break
device considerations. And the pink bunny implications of battery life and issues of disposable versus
rechargeable/embedded will play an important role in your application’s success.
Devices offer a variety of application “lives” based on their batteries. For example, wireless PDAs may
get a few weeks worth of use, cell phones a few days and two-way data devices somewhere in between.
How these average battery lives complement your application is something to evaluate but what happens
when batteries die is the more pertinent question.
Field service representatives can’t afford to have an application quit on them during the course of their
day. But it’s a tolerable risk if popping two new alkalines puts them back in business. Rechargeable
batteries offer similar survival benefits - as long as they retain their charge until required for duty.
In contrast, embedded rechargeable batteries present some unique challenges. They can’t always be
swapped easily and often require time on a charging cradle. Depending on the application and user
circumstances, the latter scenario might not be appropriate.
Some wireless devices complicate the predictable “life” issue with separate battery types for the device
and its wireless modem. And under these mixed environment circumstances it’s very probable for one
battery to die while the other has hours of useful life.
Integrated devices pose unique challenges as well. Some incorporate separate internal batteries to build
the extra “wireless” transmission power that standard disposable batteries can’t provide. It’s a clever
solution but can lead to limited wireless up-time - and even delays - as the internal battery recharges.
Batteries power the wireless devices and in turn your application. Make sure you give yours every
opportunity to keep going and going.
Durability
Like batteries, device durability is another physical issue to consider when evaluating your hardware
options. How will the device stand up to the rigors of everyday use?
It wouldn’t matter much if you had atomic-powered devices, offering unlimited hours of application
time, if the device falls apart the first time its dropped. And lest there be any doubt, it is going to get
dropped: on the ground, on the asphalt, in the sink. You name it and somebody’s probably dropped it
there.
In this instance your best defense against clumsy users is a good offense: purchase some devices and
start dropping them. Or better yet, have someone else drop them - just in case the boss is watching.
Pushing a device to its breaking point can provide valuable information. You may discover that the
battery door comes off a little too easily or that clamshell shapes provide an extra cushion of protection.
Just how much weight can an LCD screen handle before it cracks?
It’s important to understand your users and their application environment. Devices with tiny keyboards
might not be appropriate if construction site dirt and grime can get lodged between the keys. And touch
screens can be rendered useless if users keep losing the stylus.
One final word of advice: you can probably skip the water test. Few electronic devices will withstand a
good dunking and live on to transmit another day. They may work for a while - after completely drying
out - but corrosion will kill them eventually.
You can’t control your users or their environment but you can give them wireless devices that are up to
the challenges.
Transport and Access
Size is a form factor issue affecting the practicality and fit between device and application. But
sometimes you need to look a little further. How users carry and access their wireless devices plays a
bigger role in application success than you might imagine.
Devices fall into three broad “transport” categories: wearable, pocketable and luggable. Wearable means
you can attach the device to your person. That includes built-in belt clips or attachable carrying pouches.
Pocketable suggests a slightly larger form factor but one that easily slides into a shirt or pants pocket.
But if the device is too big and/or bulky it falls into the luggable category - and a set of constraints all its
own.
With the first two categories there’s a good chance the wireless device will remain with your users - all
or at least most of the time. That’s an important consideration if notification, immediacy or “pushing”
data plays an important part of the application. Examples include notification sent to delivery persons,
canceling or confirming their next appointment or sending pertinent contact information to a salesperson
on the go.
Pocketable devices are less of a notification “sure thing” than wearable devices, because users can
inadvertently leave them behind. And obviously, notification services work only if the device is capable
- not all of them are.
If timeliness is not a major issue then luggable devices can make great wireless companions. But it’s
trickier to predict how users will take to them or incorporate them into a daily routine. A device that’s
too bulky or inconvenient to use could find itself at the bottom of a briefcase, purse or toolbox, along
with your application.
That’s why there are special challenges involved with luggable devices. They may be the most full-
featured wireless companions out there, but if those features don’t improve, simplify or empower
someone on the job it doesn’t much matter.
Give your users a great application on a device that’s convenient to use and carry and you may never
hear about it. But give them one that’s awkward and cumbersome and you may never hear the end of it.
Peripherals & Expansion Slots
Many wireless devices are fixed products; what you see is what you get. But others can be expanded
through peripherals and add-on modules. If there’s any chance your application could be enhanced with
optional hardware - today or in the future - you should consider the benefits of expansion capabilities in
your device selection.
Peripherals and expansion modules allow devices to morph into other things. PDAs can become cell
phones. Cell phones can become cameras or bar code readers. And a new piece of hardware opens up
the application opportunities considerably.
For example, a PDA with a wireless interface makes for a great inventory tracking system but the
application could be ten times as efficient and accurate with a bar code reader. Digital cameras present
some unique application and service opportunities as well, and they don’t all center on sending pictures
to grandma.
Not all wireless devices directly incorporate peripherals or include add-on strategies. In some instances,
third parties have fashioned peripheral solutions around them anyway. In fact, some devices wouldn’t
be “wireless” without a peripheral. In the long run, technologies like Bluetooth leave the door open for
almost any device to become a peripheral of another - with the right software.
If there’s a place for peripherals in your application’s future, research what’s available when and from
whom - waiting for a manufacturer to deliver a peripheral could be a risky move. Be mindful of the
cost implications as well, since peripherals can add significantly to the solution’s price tag.
If expansion slots and peripherals are not germane to your application’s present or future needs then you
may want to steer clear. Expansion capabilities are not ideal or required for every wireless application.
And you may be giving something else up for a luxury you’d best do without.
Peer-to-Peer
Peer-to-peer capability seems a bit more fun than functional but it’s a device feature not to overlook in
your selection process. Better known as “beaming,” the infra red (IR) port on many wireless devices
adds a layer of capability with considerable value. And peer-to-peer is a feature that all wireless devices
will likely have in the not-too-distant future.
IR capability is much more than a way to beam your business “card” to another individual - although
that’s still pretty cool. With peer-to-peer capability, your device can create its own personal network,
communicating and exchanging information, data or even complete applications with whoever comes
within a few feet.
The implications are considerable when it comes to wireless applications. Peer-to-peer could serve as a
way of virally distributing your applications, patches or updates without relying on the wireless or wired
network. And while it may seem counterintuitive to bypass the wireless network for a wireless
application, just think about all the places wireless doesn’t yet penetrate.
Of course, there are limitations. Most importantly the devices need to be compatible or even run the
same OS. Palms can talk to other Palms or Handspring devices but they’d have little to say to a
Pagewriter or Pocket PC. They could exchange “data” if the applications supported it, but beaming
applications across OS types isn’t usually an option.
A bigger limitation is that many devices don’t have peer-to-peer capability, so if it’s a feature you’d like
to incorporate your device options dwindle. PDAs are the most common devices with IR ports although
there are also a few cell phones with the technology.
Bluetooth should change all that. The expectations - and hype factor - are pretty high for Bluetooth and
its personal area network (PAN) concept. We’re still a couple of years away from the proliferation of
this type of technology - at a reasonable cost - but it’s a good bet that it is going to happen.
Peer-to-peer capability hasn’t lived up to its original expectations but “beaming” has plenty of
application potential. Could it be in the cards for yours?
Beyond the Physical
All of the above are worth considering as you evaluate and select the right devices for your particular
wireless application. Some may be relevant, others not. But these “physical” characteristics aren’t all
there is to consider.
Equally as important are the device software issues such as operating systems, middleware, other
applications and development tools. And as much as we’d like to think it shouldn’t matter, there is the
question of device start-up and lifecycle cost. We’ll tackle these next time.
Next Up: Selecting the Right Device - Part 2
About Outr.Net
Outr.Net (www.outr.net) specializes in the design and implementation of customized, end-to-end wireless applications. The company’s experience with a variety of devices, networks, middleware and infrastructure expedites the delivery of production-quality wireless solutions. Outr.Net applications maximize end-user productivity and reduce operating costs by leveraging the capabilities of programmable wireless devices.
Outr.Net provides assistance at any stage of the application development process and delivers turnkey wireless solutions as well as individual system components. The company has real-world experience in many vertical markets, including finance, travel, medical, dispatch, sales force automation, enterprise solutions and more.
Next - Get a Grip on Wireless
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The entire contents of this article are owned and copyright (c)2001, Outr.net. Any redistribution or retransmission in whole or in part without contacting WDN and Outr.net is strictly prohibited.
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