Hardware/Software UI Relationship

Al Johnson openmoko at mazikeen.demon.co.uk
Tue Jul 17 02:24:16 CEST 2007

On Monday 16 July 2007 23:00, David Duardo wrote:
> This is where I ran into trouble As high resolution as the the LCD is,
> it simply is too small to be used with a finger based user interface,
> which is what most people would want to use on a cellphone because it is
> most convenient. At the upper bound, with the Neo1973, you can have 3
> columns by 4 rows of buttons that are of a comfortable size (.5x.5
> inch^2). Actually, the buttons can be slightly smaller and more compact,
> but I'm estimating for people with slightly bigger fingers. You can see
> can see what I mean in the following image:
> http://img107.imageshack.us/my.php?image=neo1973screenwq9.png
> Compare this with the iPhone LCD which is only 480x320, but allows for 4
> columns by 6 rows of buttons of a comfortable size (.5x.5 inch^2). Again
> you can see what I mean in the following image:
> http://img360.imageshack.us/my.php?image=iphonescreenff5.png

This had me digging out the PDF mockup and trying things. For 1 handed thumb 
operation the Neo screen is slightly too tall for me to cover comfortably, 
but I could cope with a little more width. This makes the extra height of the 
iPhone display useless as a single-handed control surface, though it may be 
useful as an uncovered display area. 

For 2 handed operation I dug opened my trusty Psion 5. While this has a stylus 
I usually don't bother with it as it's easier to tap the screen with the 
fingernail of my index finger to avoid fingerprints on the screen. I can 
reliably hit the smallest 6mm square icons that way. Just to see how much 
difference it would make I tried the more conventional way, starting with the 
icons set to their biggest, 10mm. No problem. Still no problem at 8mm, and 
only occasional problems down at 6mm. Then again I have smallish fingers, but 
on this basis 12mm should be more than enough.

> To add salt to the wound, the Neo1973 has a bevel around the whole
> screen, which further limits the use of the outer portion of the LCD. On
> the iPhone, the screen is flush with the case, so you can have buttons
> that extend all the way to the extremes of the screen.

I find the bevel at the edge of my laptop  touchpad actually enhances 
operation around the edges by giving tactile feedback as to where the edge 
is. This makes the scrolling function with the synaptics driver much easier 
to use than on a machine I tried recently with it flush mounted.

> I'm fully aware that the Neo1973 is a 1st generation device, but from my
> perspective, based on the choice of LCD and the current softare found in
> the qemu image, this first phone seems to be heading in the direction of
> a PDA with phone capabilities rather than a phone that happens to have
> PDA like capabilities .

For me anything relying solely on a touchscreen is already too big to be 
primarily a phone. If I'm going to carry anything that big I want a 
functional replacement for my Psion with ease if use to match, and the Neo 
might just make it, minus the excellent keyboard and battery life of course.

> Is this where the community wants to go? To have an open source PDA like
> the Zaurus, but with phone capabilities?

I suspect different parts of the community want different things. I still love 
the Psion 5 form factor and would love to see a worthy successor to mix with 
a small, simple phone like the old Nokia 8210. Maybe I'll be lucky with a 
later model ;-)

More information about the community mailing list