Research scientists from the Universitat Politècnica de València and the University of Stuttgart are seeking to address the difficulties of communicating with wearable devices by the experimental use of two differently-scaled and variously-abled miniature onscreen keyboards [PDF].

The research teams, consisting of Luis A. Leiva, Alireza Sahami, Alejandro Catalá, Niels Henze, and Albrecht Schmidt – compared two software keyboard prototypes called Callout and ZShift, comparing their performance in tests to Carnegie Mellon University’s 2013 attempt at a soft keyboard for tiny screens, ZoomBoard.


The problem being addressed in the research is the opacity of wearable devices, which often lack any direct interface with the user, but usually can only be accessed – if at all – via a satellite interface in a connected mobile app – or by such tokens as motion, initially made famous by the iPod Shuffle’s ability to randomise tracks according to the user shaking the device.

Research leader Luis Leiva of the Pattern Recognition and Human Language Technology research centre at the Universitat Politècnica de València, said: “QWERTY keyboards, despite their limitations, have the fundamental advantage that users are already familiarized with the layout and the text entry technique is very easy to understand,”

ZoomBoard, the established keyboard in the trials, is a multi-tap QWERTY board wherein the user is shown an enlarged section of the keyboard over the region that they initially tapped. After this the character input is completed with a second tap on the appropriate key revealed in the zoomed area obscured by the user’s finger.

Callout, which is designed for the smallest screens, displays to the user the character hit, in the area above the part of the interface that their finger is occluding. The user can then drag their finger over to the correct key, if necessary, and input it by lifting their finger off the screen.

ZShift instead mirrors the area of the QWERTY keyboard hidden by the user’s finger, presenting a magnifying-glass-style zoom circle over the area covered by the user’s roving finger, allowing the user to visually land on the correct key, if they didn’t land on it in the first place.

samsung-nexus-test[1]In the tests Carnegie Mellon’s original soft keyboard scored more or less equally with the researchers’ own ZShift, though one participant in the tests reported that ZoomBoard was ‘irritating’ on the larger of the three form-factor mini-screens tried – and these were simulated with a customised version of Firefox running in full-screen mode on a Samsung Nexus S running Android (ill. right).

In all cases Words per Minute (WPM) never exceeded or reached 8, with ZoomBoard scoring highest on the medium-sized mini-screen, and Callout bottoming the table at 4.3 WPM. Research subjects warmed up by typing in their own names before being asked to type in a series of phrases from a set resource of phrases often used in input device research. Though less than half of the university test subjects were women, the report notes that females seemed better able to cope with the limited room for manoeuvre, and noted the problem of ‘fatfinger’.

The researchers’ findings were presented in April at the ACM conference on Human Factors in Computer Systems (CHI 2015), in Seoul, Korea.