Touch Usability

Crocodile touchscreen keyboard with triangular buttons

From The Register:

A British inventor has submitted a patent application for a wacky touchscreen keyboard design which, he claims, could spell the end for accidental key presses.

Baker told Register Hardware today that each triangular key has significantly more dead space around it than you’d find on a standard Qwerty layout. Consequently, users are more likely to press the correct key each time they tap.

Link: Triangular buttons key to touchscreen typing success -- inventor.

Hmm. The hexagonal grid design is useful, I think (see previous post) but I'm not sure that the extra dead space is always going to be so helpful, especially if you were to shrink that keyboard down to regular iPhone size so that it covers only half the screen (or, worse, to its size in portrait orientation).

There are (at least) two important aspects of soft keyboard buttons. There's the displayed button shape, and it may be true that drawing them smaller makes people more accurate, and there's also the active area's shape. The active area is the region where a touch gets accepted as that particular key. The two areas are typically not the same, and the iPhone actually resizes the active areas dynamically so that more likely letters are easier to press. (e.g. if you type 't', 'h', then the active area for 'e' will be expanded in expectation that you'll type that next.)

It gets even more complicated when you consider that there isn't just a single xy location associated with a keypress. There is a touch-down position, a lift-off position, and a stream of positions in-between. The key event is triggered when lift-off happens (typically -- because this works best for capacitive touch). But you don't want to just take that single lift-off position. It needs to be filtered somewhat to account for the fact that the trailing end of position data may be a little skewed when people lift their fingers. That filtering and other tricks mean that effectively there is not even a simple fixed "active area" for the button -- it's really dynamic and determined by the whole interaction.

All of which is to say that designing good touchscreen keyboards is a heck of a lot more complicated than creating the shape of the keys. (I'm sure this inventor knows all this -- I'm not trying to pick on him, just on the impression that this news story gives. And I haven't read his patent application.)

Nokia Poll: Users Favor Touchscreen + QWERTY for Text Input

Online polls have their problems, of course, but this one from the Nokia Conversations blog is still interesting, I think. More than half of their respondents said they'd prefer a physical qwerty keyboard plus a touchscreen over a qwerty-only or touchscreen-only phone. Link: Poll results: Touchscreen & QWERTY combo voted your perfect set-up.

TouchType fast text entry with word prediction

TouchType is an entry in the 2009 MEX Conference Awards: The MEX Mobile User Experience Awards - TouchType Express. 

It's a technology for faster text entry using an advanced prediction engine. The user spends most of the time selecting the next word instead of typing letters. According to the developer, it predicts the next word 40% of the time without the user having to type a single letter (though you have to select it from a list). Who knew email was so predictable?

It looks pretty quick in the video:

Apparently they have an iPhone app demo but it's not released to the public yet. (There is something called TouchType in the app store but it's different -- it's just a landscape keyboard for email.) 

Eyes-Free Touchscreen Dialing from Google

This directional-stroke dialer is part of a project to make Android interfaces that are accessible to blind users. The basic idea is that wherever you touch first is '5', and you stroke up to dial '2', etc.

Link: Announcing Eyes-Free Shell for Android (Google Open Source blog).

There's more, including a video, at Engadget (where the above picture is from).

This kind of swipe interface is similar to a text entry technology called JetKeys, developed by an Israeli company, JetWay Technologies. The idea of JetKeys is to use a numeric keypad for text entry by associating letters with directions on the keys, so instead of tapping the keys you swipe over them in one of four directions.

(picture captured from JetWay Technologies site)

Hexagonal button grids

Spy shots have been floating around the web of a new honeycomb-style launch screen in Windows Mobile 6.5 (Engadget, PocketNow).

I haven't read anything official about why they chose this design, but I think it's a neat idea. Packing touch regions together in a hexagonal grid is more efficient (space-wise) than a rectangular grid, and it also makes the cells closer to circles, which means they're a better fit for our (roughly circular) fingers. Some of the descriptions I've seen call the honeycomb "finger-friendly," apparently for this reason.

Whether this benefit is provable, I don't know, but it would be interesting to test it experimentally. It probably doesn't make much difference when the regions are large like on this launch screen.

It might make a difference on a soft keyboard -- if you offset the rows you could expand the touch targets to hexagons and thus they'd be a better fit for fingers (to clarify a bit more technically: the Voronoi regions formed by a diamond grid like this are hexagons, ignoring the sides).

The iPhone keyboard offsets the rows (at least the first two), but the BlackBerry Storm doesn't.

Keyboards may be a bad example, though, because they have so many other constraints and features. And both Apple and RIM have more sophisticated algorithms going on behind the scenes for prediction, etc. (Apple has said that they actively change the size of the touch targets as you type -- see this video. The targets are shown as rectangles in this video, but that may or may not be how the software works.)

In general, though, if you ever have to pack a big array of touchscreen buttons together then the best pattern might be a hexagonal grid.

p.s. Here is an image of what I mean by a keyboard with hexagonal touch targets (created with this nifty graph paper generator and Skitch).

Swype: Text entry method for touchscreens

A new company called Swype introduced their another alternative text-entry method for touchscreens this week.  It looks pretty much the same as ShapeWriter, though the demo is a little more polished.  I wonder if they licensed the same technology or if this is independent work.

Demo video and description are at TechCrunch.

Previous post about ShapeWriter: Shape writing on iPhone.

Shape Writing on iPhone

ShapeWriter has released a demo iPhone application of their technology (called WritingPad in the iTunes store).  The idea behind shape writing is that you trace a path over the letters in a word and the software matches the pattern to its dictionary of words.  The demo application lets you write notes and email them.

I installed it on my iPod Touch and it works pretty well (aside from a few crashes, but then all the new applications seem to be crashing).  I typed a few sentences and found it quite a bit faster than the virtual keyboard, at least when I'm typing common words that the ShapeWriter dictionary knows.

Shape writing is based on research done by Shumin Zhai and others at IBM.  Zhai's web page has a recent introductory article about the technology: An Introduction to Shape Writing (pdf).

Also on the text-entry front, the new iPhone software includes several international keyboards, including a Chinese handwriting interface that's fun to play with even if you don't know Chinese.

Japanese Survey on Touchscreen Use and Attitudes

Survey firm MyVoice asked over 13000 Japanese people online to answer questions about touchscreen mobile devices.  43% said they didn't want touch at all.

The site What Japan Thinks has translated and posted some of the results.  Questions were asked about attitudes towards touchscreens, anticipated uses, and current use of touchscreen devices including the iPod Touch.

Link: Touch panels: screen and soft keyboard sources of worry (What Japan Thinks).

Or in Japanese: MyVoice.co.jp.

Samsung SDI laptop concept

Engadget writes about this Samsung laptop concept design: Samsung's 12.1-inch OLED concept makes us swoon. 

Are we ready for touch panel keyboards?  Probably not quite, though the trend in laptop design does seem to be towards flatter and flatter keyboards with less travel distance, and people seem to like them.  Apple too has moved in this direction with their latest keyboard, on which I'm typing this.  So it may just be a short leap to totally flat keyboards.  Add some high-fidelity tactile feedback and they might work quite well.

Presumably the touchpad for this computer would be overlaid on the keyboard and accessible with some sort of mode switch.

UniGest: Text Entry using Wii Gestures

"UniGest" is a proposed scheme for text entry using a Wiimote.  The user holds a button while making one or two primitive motions with the controller.  It was presented as a work-in-progress paper at CHI by Steven Castelluci and Scott MacKenzie of York University.

They have constructed an alphabet and performed an initial user study to measure the time taken to perform the basic gesture primitives.  From this they derived a theoretical upper bound on text-entry speed of 28 words per minute.  Real performance is likely to be slower, but probably better than previous efforts at text entry using game controllers that achieved around 7 words per minute.

The paper is "UniGest: Text Entry Using Three Degrees of Motion" by Steven J. Castellucci and I. Scott MacKenzie.

You can download the paper from Steven Castelluci's web page.