Choosing the right P.D.A

With my preferred choice of digital device being a PDA, I couldn’t exactly just choose any type of PDA and expect it to fulfil my requirements from a designer point of view, and obviously the most important a user point of view.
An advantage of introducing a PDA to a new audience, is that’s is general interface works just like a household PC. Navigation around the device is same as we move around our windows XP application. Expect from the start button is positioned in the top right hand corner.
As you can see from these pictures below:
Picture courtesy of http://www.flickr.com/photos/16596182@N00/281089701/

Its common convention of that start button is positoned in the top left hand corner, as this is a familiar with most of the users, they natural instinct could be to start here, and begin navigating around the device just like they would do at home.
So users knoweldge of interaction will be greater and their ability to utilize the device will be much more evident when its presented in front of them.
Its just its screen size is slightly smaller!

Although this way of ‘Windows based navigation’ wouldn’t be so dominant in my interface, I could incorporate a similar interface design and layout in to my idea. The options they are presented with such as ‘Beginning new recipe’ “proceed to checkout’ ‘quit application’ (hope this never happens!) Could all be positioned at the bottom, just like a standard desktop PC, therefore giving the user much more confident as these conventions are what they are used to, and which they perform almost everyday.
This may confuse users who already use a PDA, but with the function of my devices being accessible by all types of users, I think it will be more reasonable to suit common computer users. To be honest with the prices of PDA’s being over £250 not many middle class people would, or could afford this.
It could be an idea to incorporate the Windows ‘START’ interface as a menu structure for my device.
This process of interaction from the user, wont take any time at all to get used to, and wont need much explaining, but some for that cognitive model of mine.

"Conventions, they are very useful, As a rule conventions only become conventions if they work. Well applied conventions make it easier for users to go from site to site without expending a lot of effort figuring out how things work"
(Steve Krug 'Dont make me think' p.35)

Enough of that it think for now, more information will be presented in my interface design research later on.
Before my research I thought there was only one type of PDA, but in fact there are two, well you learn something everyday don’t you! Any way here are the two types of PDA:

• Handheld PDA
• Palm PDA

And from this website
http://www.findarticles.com/p/articles/mi_m0ICC/is_7_69/ai_69239315

I can begin to draw a comparison between the two, and find out which one best suits my function for visual display.
If i am going to implement these on the shopping carts within the store, the money side is only a slight concern of mine, if the users had to buy one, then this would of course be much different. But as i am about to explain 'You Get What You Pay For' and PDA's are no different.
As my device is going to run a single visual application, the resolutions and screen szies are going to be the main factor. The handheld (pocket PC) offers a high resolution, ideal for me as a designer as the space, all be it limited starts at 320 x 240 pixel resolution, compared to a 160 x 160 palm PDA. this means a the qaulity of the image within a given size, the greater the pixels the sharper the image.

This explaination and picture is courtesy of http://en.wikipedia.org/wiki/Image_resolution

Pixel resolution

"The term resolution is often used as a pixel count in digital imaging, even though American, Japanese, and international standards specify that it should not be so used, at least in the digital camera field. An image of N pixels high by M pixels wide can have any resolution less than N lines per picture height, or N TV lines. But when the pixel counts are referred to as resolution, the convention is to describe the pixel resolution with the set of two positive integer numbers, where the first number is the number of pixel columns (width) and the second is the number of pixel rows (height), for example as 640 by 480. Another popular convention is to cite resolution as the total number of pixels in the image, typically given as number of megapixels, which can be calculated by multiplying pixel columns by pixel rows and dividing by one million. Other conventions include describing pixels per length unit or pixels per area unit, such as pixels per inch or per square inch. None of these pixel resolutions are true resolutions, but they are widely referred to as such; they serve as upper bounds on image resolution.

Below is an illustration of how the same image might appear at different pixel resolutions, if the pixels were poorly rendered as sharp squares (normally, a smooth image reconstruction from pixels would be preferred, but for illustration of pixels, the sharp squares make the point better)."

Of course the more money you pay, the resolution we become much greater on the PDA, so finding any bigger, would benefit me for the designing, but even this size would be adequate.
It also offers the ability of handling 16-bit- 65,000 colours; this will allow my interface images and colours to be much clearer and more true. Theses strength will make product packaging, and images on the interface more recognisable and distinctive.

And finally for the screen sizes, an obvious constraint for me as a designer, It won’t be as easy as designing for the web, completely the opposite I expect.
Screen sizes are measured diagonal. Ranging 2.2inches up to a massive 4.5inches. I say ‘massive’ but in relation to the device this is very big. The more room on the screen, the better the interface will be as everything is evenly spread out over the interface, and not all crammed into a small space. Also it think from a user point of view the larger the screen the better interaction they will have with the device. It is very difficult to show a true image on this blogger site with regards to the size. But obviously the bigger the screen, the easier it will be to design for.

the PDA which i am going to be designer for needs to be a Handheld PDA, simply for the fact that is can handle high graphics, better image quality, and the main reason it that they have a larger screen dimension to that of a palm PDA.
Running a simple, single application on the PDA, these quality will help the user as they interact with the device more easily and more confortably. If their interaction is precisely that, then I have a good chance in succeeding with this device.

Here are some links to help you choose the right PDA for you

http://www.pdamd.com/vertical/tutorials/buyersguide2.xml
http://www.webmonkey.com/webmonkey/98/39/index4a.html?tw=archives
http://www.bizhelp24.com/it/choosing-the-right-pda-personal-digital-assistant--4.html
http://www.digitalnetwork.co.nz/choosingaPDA.htm