Human Factors Criteria for the Design and Acquisition of ... - FAA

Keyboards June 20049.14 MembranekeyboardDescription. Membrane keyboards are thin, flat,pressure sensitive devices with areas marked to indicatespecific keys. They are different from traditionalkeyboards in that they have little or no key travel. Theyare also different from touch-screens both in technologyand use. Touch-screens have broader applications thanmembrane keyboards in that they are used not only forkeying in data but often for point and click typeapplications. Pressure sensitive keys, such as in touchpads and poke boards, are suitable for occasional keyingtasks, but are not recommended for more repetitiveoperations. [Source: Hashimoto & Togasi, 1995; Hunter, Zhai, &Smith, 2000; Kodak citing Klemmer, 1971; Zhai, Sue, & Accot,2002]9.14.1 Use. Membrane keyboards should be used fortasks when only occasional data entry is necessary.[Source: Cohen, 1982; Loeb, 1983]Additional information. Performance is worse onmembrane keyboards than traditional keyboards. Textentry is slower. [Source: Cohen, 1982; Loeb, 1983]9.14.2 Force. Force to operate a membrane keyboardshould be about .6 N (2 ounce-force). [Source: Stevens,1975, cited in Kodak]Additional information. Requiring a minimum activationforce reduces the possibility of accidental activation.9.14.3 Feedback. Membrane keyboards should haveeither a raised dome over the keys and/or auditoryfeedback. [Source: Roe et al., 1984]Additional information. The presence of a dome allowsusers to locate the keys by touch and provides tactilefeedback. The combined use of raised domes andauditory feedback decreases errors and increases typingspeed. [Source: Roe et al., 1984]9-38