Timers and Minutes

Say you were building the user interface for an oven timer. This timer only had room to display four digits. How do you handle the moment when the user has entered a new time and the timer starts ticking down?

The Models

Say the user entered 00:15 (fifteen minutes) and started the timer. One second after that, the timer is actually at 00:14:59, but we don’t have the room to display all of that. On my particular stove, the display stays at 00:15 all the way until 00:14:01, and at 00:14:00 it changes to 00:14. I’m calling this the pessimistic model, as it shows you there is more time left than there really is 98.3% of the time.

On the stove in my last apartment, the timer also only had four digits, but the behavior was different. At 00:14:59, the timer displayed 00:14. I’m calling this the optimistic model because it is showing less time than there is really left 98.3% of the time (assuming 00:14 == 00:14:00).

An alternative technique might be the modest model. Say the timer changed at the 30-second marks, so 00:14:31 would display 00:15 and 00:14:30 would display 00:14. This feels closer to home as far as matching mathematical rounding, where 0.5 might be rounded up to 1 and 0.49 down to 0 for traditional integer rounding. This is that equivalent only with minutes and seconds. The problem doesn’t get any better though unfortunately, even with this method it is possible for a glance at the clock to be wrong by 59 seconds.

The Post Set

An interesting consideration is what happens the second after the timer is set. The most unsettling is the optimistic model. Just a second after the timer sets, the timer no longer reads what you just entered but shows a minute less instead. Even though I understand at an intellectual level what is happening there, it’s still a bit weird. The pessimistic and modest models don’t have that problem.

A Better Way

In this specific example of only having four digits available, the best way would be to have the timer be aware if there is less than one hour left. In less-than-an-hour mode seconds would tick down on the right and minutes shown on the left. Otherwise, hours on the left and minutes on the right. No explanation of that is needed, which is a good sign for a UI. If over an hour is needed, I think the pessimistic mode is my favorite.

7 responses to “Timers and Minutes”

  1. traq says:

    I agree about the “better way,” but when it comes to the other three, I have to choose the “pessimist.”

    And here’s why:

    The user -sees- it happen.

    If the user walks away after setting the timer (and logically, not many people will set a timer and then sit and watch), they’ll have no way of distinguishing between the “optimist” and “modest” models.

    But with the “pessimist,” the user knows right away what’s going on, and know how to best interpret the display. Same thing with the “better way” – it doesn’t take long to tell if the display is ticking away (must mean 14 -minutes- and 10 -seconds-) or sitting calmly (must be 14 -hours- and 10 -minutes-).

  2. traq says:

    dang it, I mixed up the terms (you can probably figure it out from the context, but dang it…!).

    I’m actually in favor of the “Optimist” model… If I could edit it, I would…

  3. Gray says:

    I’ve surprisingly also always hated this problem. My solution is that when it goes from hours and minutes to minutes and seconds you switch the display.

    For example:

    01:30 – 1 hour, 30min
    15:45, 15:44, 15:43 – 15mim 45sec, 15min 44sec, etc…

  4. Bert de Vries says:

    The real problem here is that seconds are not ‘visible’. So the most simple solution is to add two more digits. Or some other way to give the ‘user’ an idea of the seconds within a minute, like a progress bar or intensity of the digits.

  5. Jesse says:

    What about the last minute of the countdown as you approach and achieve 0:00? I think that this moment is more important that the moment the timer starts.

    With the optimistic model, the timer would show 0 for the whole last minute which seems confusing and completely incorrect. The pessimistic model would read 1 minute until it actually reaches 0, which makes sense to me, as I take it to be saying “We are in the last remaining minute.” Then 0 would appear when you actually have 0 time remaining.

    I like the Better way, except that at a glance you don’t know if you are reading Hours:Minutes or Minutes:Seconds. You would have to wait for up to 59 seconds to find out which mode the timer is in.

  6. Adrian says:

    I agree about the “better way”. I like the pessimistic model otherwise, however, I have a different proposal.

    Under the pessimistic model, there is no sign that the timer has started, so although the amount of time remaining is more intuitive, the user might worry that the timer hasn’t started. If there is no ability for the device to beep (or some other signal of the sort), blinking the numbers would be a good alternative.

    Another possible alternative (although I’m not so sure about it) is switching between hour and minute display and minute and second display. It would give more information, but might confuse the user.

  7. brendan says:

    I would make the top dot of the colon blink once ever second from 59 down to 31, and the bottom dot blink from 30 down. Pair this with the pessimistic mode to give a fairly decent idea of how the timer is working.

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