Alarm Clock

Problem Description

BNNNGHT! BNNNGHT! BNNNGHT! BNNNGHT! Time to get up? Maybe I'll just snooze once. No, I can afford to sleep a bit this morning, I'll reset the alarm for another 45 minutes. BNNNGHT! BNNNGHT! BNNNGHT! BNNNGHT!

Many mornings, I attempt to get up at an early time, but think better of that decision when I realize how non-refreshed I feel. Sometimes, I try hitting the snooze, and then decide to sleep a bit longer than the snooze time. On these occasions, the alarm sounds "early", and I don't get the amount of extra sleep that I intended.

My alarm clock.

HCI Analysis

The major cause of this problem is that there is no indication of whether the snooze function is active. If the snooze button is hit, the alarm will sound exactly 9 minutes later, regardless of whether the alarm time has been changed after the snooze button was hit. To turn off the impending snooze alarm, it is necessary to turn the alarm switch to the OFF position. It must then be turned back on if the user desires the alarm to sound at the set time.

Early in the morning, attention is a problem for most users. This makes highly visible feedback essential, so that users are able to bridge the gulf of evaluation (Norman, 1988). Until this problem had occurred a few times, I held a faulty mental model of the clock, thinking that there was only one alarm setting, and that if I changed the main alarm time, the snooze setting would be erased.

Recommendation

Users need to have feedback about the state of the system, as well as how to get out of that state if desired (Apple, 1992). Adding a simple light to indicate that the snooze was on would help a great deal. An even better solution would be to have a scaled indicator that shows how much time is left before the alarm sounds again.

This problem could be alleviated if the clock sensed the alarm time being changed, and unset the snooze alarm at that time. Of course, feedback would still be helpful to let the user know that the snooze alarm was no longer armed.

References

Apple Computer (1992) Macintosh Human Interface Guidlines. Addison Wesley. [Chapter 1]

Norman, D. (1988) The Psychology of Everyday Things. New York: Basic Books [Chapter 2]

rscherle@cs.indiana.edu
Last modified: Fri Mar 26 15:33:36 EST 1999