טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentMenirom Michael
SubjectThe Study of Portable Phone Keypad Suitability for Text
Message Typing, and the Design Guidelines for
an Improved Keypad
DepartmentDepartment of Architecture and Town Planning
Supervisor Professor Ron Nabarro
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

Over the last two decades, cellular telephones have entered into our daily lives. Cellular telephones are equipped with screens and an alphabetic keypad; which enable a new kind of written communication, the SMS - short message service.

Most users prefer typing SMS with their thumb which is of low dexterity. The problem is that over the years; cellular telephones and their keypads have grown smaller. The repetitive movement of the thumb in a limited area; and the typical square key arrangement which is not consistent with the thumb’s natural movement, might cause injury.

This injury is called TMI - Text Message Injury. It is relatively new and there is no knowledge as to the number of people suffering from it. To date only a few cases, world wide, were diagnosed with serious SMS typing related injuries. 

The thumb’s biomechanical movement can be translated into a two dimensional arch. I therefore suggested that an arched keypad, which is consistent with the thumb’s movement radius, may be better ergonomically suited for text message typing than a conventional straight keypad.

I had designed three arched keypad model variations; which were based on the standard MULTITAP arrangement. The models varied in width, size and distance between buttons. These keypads were compared to a square keypad design.

The tested parameters were both objective (typing rate, number and type of mistakes), and subjective (comfort of use, willingness to use the product).

Each examinee was asked to type a long sentence, and a short letter sequence on each of the four models.

My experiment showed that although most examinees were experienced in using a square keypad, one of the arched keypad models had faster typing results and ranked higher comfort marks. This was especially evident for the tested male population, most probably because that keypad model was better ergonomically suited for a larger male hand.

No difference was found in the number and type of mistakes made, in comparison between the arched keypad models and the standard keypad. 

An increase was shown in the number of examinees interested in purchasing a cellular phone with an arched keypad at the end of the test.

These test results may lead to the conclusion that some of the arched keypad models show objective advantages in text message typing, to a square keypad, and that text message typing speed and comfort may be improved by geometrically changing the keypad.