On Jun 06, 07 15:21:38 +0200, Lukas Ocilka wrote:
Martin Schmidkunz wrote:
The light switches vs. fire alarm buttons is an excellent example. If you look closely at the fire alarms you will also notice that putting a red frame around the button is not sufficient to protect it from misuses: usually it is hidden behind glass and you have an additional explanation message. Which can be taken as a proof, that different semantics have to be explained to the user.
I fully agree. But this explanation is not necesarily done in words. If I expect a light switch, and my fingers hit the metal frame with the glass front, I immedialty realize this is not an ordinary light switch. The feedback, which I get from the device includes sufficient 'explanation' about the device itself. I may not fully understand (without looking at) what it really is, but it tells that my expectations were wrong, which is the most important information here.
The "light switches vs. fire alarm buttons" is rather a philosophical case :)
Imagine that fire alarm buttons looked the same as light switches but had a red frame around. Then, what are the light switches good for? You very often need to press them in an absolute dark just to turn the light on. In an absolute dark, you wouldn't see a red frame around an alarm button and you might think it is a light switch. That could cause a harm or/and a damage by starting a fire alarm instead of turning the light on.
An explanatory message is not the most important part. The most important is that it is different to a common light switches and that it attracts your attention.
Absolutly. A written message is a nice add on, but insufficient here. Besides giving tactile feedback in addition to optical, the metal frame has another purpose. It avoids false alert caused by a careless user, who just slams his hand against the wall, in a manner that is usually sufficient to toggle a light switch. With the sturdy frame around the fire alarm button, nothing happens. This again attracts the users attention.
The only possible consistency is to have all light switches the same and then all fire alarm buttons also the same type but a completely different to light switches. Then, neither light switches nor fire alarm buttons need to be explained... consistency is self-explanatory ;)
Fire alarm buttons and light switches have more in common than one may realize at first glance. They both send out a number of identical messages: "I am a switch!" "I belong to the building, not some furniture!", "Use your hand (or elbow) to operate me!" "You can touch me without activating me!" All switches, (be they light switches, or alarm buttons) should be wall-mounted. None at doors, tables, floor or ceiling or dangling at loose wires. All are at an average height where one expects such a switch, and all should be near doors or other easily reachable locations. All switches have a size and require a force that is suitable for a human hand, and the mechanical action should be one of the standard press or flip actions that one expects. All switches provide two levels of feedback to acknowledge their activation: (1) mechanical movement, (2) lights on / alarm sounded. That is a lot of consistency already, isn't it? The light switch just sends some additional message: "Try me, nothing bad will happen!" "I have two obvious positions, my activation is easily reversible!" Whereas the fire-alarm button says: "Are you sure?" "Take care, I may hurt your fingers!" cheers, Jw. -- o \ Juergen Weigert paint it green! __/ _=======.=======_ <V> | jw@suse.de wide open suse_/ _---|____________\/ \ | 0911 74053-508 (tm)__/ (____/ /\ (/) | __________________________/ _/ \_ vim:set sw=2 wm=8 SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nuernberg) "Oral agreements are worth about as much as the paper they are written on." -- To unsubscribe, e-mail: opensuse-ux+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-ux+help@opensuse.org