Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!brunix!doorknob!rsw From: rsw@cs.brown.EDU (Bob Weiner) Newsgroups: comp.human-factors Subject: Re: Touchscreens Message-ID: Date: 13 Jun 91 18:37:19 GMT References: <8435@awdprime.UUCP> <6460@ns-mx.uiowa.edu> Sender: news@brunix.UUCP Organization: Brown U. Lines: 73 In-reply-to: jones@pyrite.cs.uiowa.edu's message of 13 Jun 91 14:18:34 GMT In article <6460@ns-mx.uiowa.edu> jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H MLH,3193350740,3193382879) writes: > From article <8435@awdprime.UUCP>, by jon@kitty.austin.ibm.com (Werner): > > I don't know of any papers, but as a long-term touch-panel user, I much > prefer mice, trackballs, or knobs on my keyboard. > > I used the U of Illinois Plato touch panels between 1973 and 1980, and > the big problems are: Mr. Jones painful experiences with touchscreens is a fine example of why a newsgroup like this exists. Often computer interface designers know little about ergonomics and usability and they put everything they know into their designs. Present a new technology and they try to make it fit with their old designs rather than contemplating the liberating aspects of the technology. Touchscreens hold much promise because of the greater level of direct manipulation they provide over indirect pointing devices. But interfaces need to be designed for direct versus indirect pointing. > > 1) You have to lift your hand up from the keyboard, perhaps a foot, > to touch the screen. This slows you down compared to horizontal > moves to a mouse. Mount the screen in a desk at a slight upward angle. You still have to move your hand but not as far and you don't have to raise your arm. A keyboard tray can be made to swing up and over or down and under out of the way for intensive touch screening. Some notebook computers will not have a keyboard but will rely solely on a touchscreen and pen input. > > 2) No matter how good the anti-reflection coating on your screen is, > fingerprints tend to defeat it. If you've got a touch panel, you'll > need to wash it almost daily to keep the glare down. Find a nicely balanced pen-like object with a blunt end and use it. No fingerprints. A number of touch screens do not actually require that their surface be touched but humans seem to love to jam their fingertips forward. My rule is that fingers should never touch a CRT, especially when indicating a point on a screen to a friend. Everyone should learn this. > > 3) If you have touch-intensive software, where you spend long periods > holding your hand up to the screen poking here and there, your arm > gets tired. I remember after some sessions debugging a particular > touch-intensive piece of computer aided instructional material, my > arm began to ache quite intensely. I've never experienced that kind > of reaction to "desktop pointers" like mice. > Carefully contoured desktops with wrist supports and the screen embedded in the desk can eliminate most of this fatigue. > 4) Touch panels aren't particularly accurate. Even if you use a modern > thin-film touch panel, there is a real problem with paralax. Shouldn't flat screens reduce this? > The > front of a CRT display is quite thick, and the push button size we > typically use with mice is small enough that it can be very hard to > find the right spot on the screen to touch to get a particular > button and not its surrounding area. Mice and touch screen interfaces should not work the same way, although they may have many similariities to maintain interface consistency. With different interfaces can come different actuator object sizes. -- Bob Weiner rsw@cs.brown.edu