ClockUserInterfaces ...
I have nearly completed the twice-yearly ritual of adjusting all our clocks to account for the daylight saving time change. There are clocks that I don't mind setting, and others that are a genuine pain in the neck. I wonder why this should be so - why would it be hard to design a user interface for setting a clock ahead or back by one hour? And isn't that the most common thing that we do when we set the time on our clocks?
I've made a catalog of some of the best and the worst of our clocks.
We have 2 clocks that are fully automatic. They are so-called 'atomic' clocks. Of course, they are not really atomic - they are driven by ordinary AAA alkaline batteries. But they have radio receivers tuned to WWV and some logic to decode the WWV time signal. (And the WWV uses the NIST atomic clocks when generating their signal, hence these are 'atomic' clocks - get it?) These are wonderful clocks. They automatically adjust for the daylight saving time change, and I have to do nothing whatsoever.
I have had this clock radio since 1983. I got it for free for listening to a one hour sales spiel for ... I don't remember, maybe a timeshare condo or something. This clock has been a real marvel. It has endured years of abuse on mornings when I smash down on the snooze button with undue force. It has lived through drywall demolition, uncovered and filled with gypsum dust. It still works perfectly.
The clock is rather large, maybe 10 inches by 6 inches. It has 2 buttons and a slide switch. The buttons are labelled 'Hour' and 'Minute'. The slide switch is labelled 'FWD - LOCK - REV'. To set the clock an hour ahead or an hour back you slide the switch to 'FWD' or 'REV', then press the 'HOUR' button once, then set the slide switch back to its center LOCK position.
Excellent!
We have a couple of these. They are the battery powered quartz crystal type of clock with an analog face. There is a small wheel on the back on the battery holder. You rotate the wheel in the appropriate direction while watching the front of the clock until you have reached the correct time.
This isn't bad, but you do have to have another clock or watch available to check the time, or simply remember which minute you were on before you started to set the clock. But for $8.95, I can live with this.
Our microwave clock is pretty typical. You press the 'Clock' button, then use the numeric keypad to enter the time. It doesn't have a 24-hour setting, as far as I know, so if you set the time in the afternoon you simply set it to whatever 12-hour time it is (like 2:24).
Our new oven is similar, except that it doesn't have a numeric keypad. It just has UP and DOWN buttons. To set the time you press the Clock button, which blanks the display, then press it again, which turns the display back on, but now the time display is blinking. You then press the UP or DOWN button to adjust the time. If you press and release the time changes by one minute. If you press and hold the time starts adjusting by 10 minute increments.
You have to remember that these are digital clocks and are amazingly accurate. The only time I ever have to set them is at the daylight saving time switchover and after a power outage (which, thankfully, does not occur often). So fully half the time that I set these clocks it is for daylight saving time. But neither device has an easy means of changing the time by exactly one hour.
Car stereo manufacturers seem to delight in making it challenging to set the clock. Actually, after you've figured out how to do it it's not terribly difficult. But the manufacturers apparently spend a great deal of time figuring out clever ways of hiding the magic handshake needed to initiate the clock-setting process.
In my case there actually is a button labelled 'clock'. It is a small, shy, and retiring button. If you press it, the clock display disappears. If you press it again the clock display re-appears. Hmmm. OK, so you press and hold it. Then the clock display starts blinking. Bingo! Now what? Well, the buttons used for the radio presets have small and very hard to read labels above them. Two of those labels are 'hour' and 'minute'. So, to set the hour back to standard time in October, you press the 'hour' button, 11 times, until the correct hour shows up. Be sure to do this quickly, because if you delay for 2 seconds, the time-setting function no longer works, and you are simply selecting preset number 1, repeatedly.
We have a combination 'atomic' clock, indoor, and outdoor thermometer. It is
huge - about 8 inches by 12 inches. It displays the current month, day of month, day of week, moon phase (really), time of day, outdoor temperature, and indoor temperature. There is a remote device that I have mounted to the exterior north wall of our house that has a radio transmitter that periodically broadcasts the outdoor temperature. The device inside has a radio receiver to receive those broadcasts. The device also uses its radio receiver to receive the WWV time signal. The device can display temperature in fahrenheit or celcius, and can show days of the week in English, French, Spanish, German, and, for all I know, Esperanto and Tagalog. The device will be happy to display the current time on a 24 hour clock or a 12 hour clock.
Oh, and did I mention? The device can also serve as an alarm.
In short, an amazing and useful gadget.
Unfortunately, the user interface on this device is horrible. There are no buttons on the front of the device. There are 4 buttons on the back. Two of those buttons are devoted to the alarm function, the other 2 are for changing all the other settings.
So, to set the clock ahead or back one hour you
- sit in a comfortable, well-lighted place with the device in your lap
- you turn the device around and identify the 2 buttons you will be pushing
- you position 2 fingers over those 2 buttons, then turn the device around so the display is facing you
- you begin pushing the 'function select' button. Repeatedly. You will see various parts of the display begin to flash. You will have the opportunity to change the language, time-zone, day of week, day of month, month, fahrenheit/celcius, 12/24 hour clock display, DST on/off, hour, minute.
- Oops - when you see the hour begin to flash, press the other button until it shows the desired time. That would be 11 presses in the autumn.
- Press the first button to make the minutes flash. But you don't have to change anything here, so press the first button again.
- Now, and this is important, when you've pressed that first button and absolutely nothing is flashing on the display, STOP PRESSING BUTTONS. Because if you press that first button again you will have to cycle through all the settings, again.
Well. This is horrible on so many levels.
- Having made certain fundamental decisions once (like language, time zone, fahrenheit/celcius, 12/24 hour clock), why must I see those settings again when all I want to do is change the time of day?
- The device is huge. But the display only occupies about 30% of the available area. The rest is simply decorative plastic. Why not put the buttons, and more of them, on the front so you don't have to be a 2-fingered accordionist to set the time?
- Since it is receiving the WWV time signal, why doesn't it adjust automatically for DST?
We have a setback thermostat with a digital display and an array of push buttons. It has a clearly labelled button called 'set current day/time'. Next to it are buttons labelled 'Time Up', 'Time Down', and 'Day >>'. I naively thought that the procedure would be to press the 'set current day/time' button, then press the 'Time Down' button until I reached the desired time. Hmmmm, no. That wasn't right. Actually, to set the hour you press the 'set current day/time' button, then each time you press it again it adjusts the time by one hour ahead. Press it 23 times, then press 'Run Program', and voila! the time is set. Actually, maybe the 'Time Down' button would have worked, but to actually store the setting you need to press the 'Run Program' button, and NOT the 'set current day/time' button.
This is actually not a bad user interface, but it suffers from spillover effects from other similar user interfaces. On digital devices the common pattern is : 1) press a 'Clock' button, 2) press a time adjust button repeatedly, 3) press the 'Clock' button again to end the cycle. But on the thermostat you have to press a different button to end the cycle, and pressing the original 'clock' button actually has the effect of
resetting or
altering what you have done before.
My wristwatch is the quartz-crystal analog-face type, with classic pull-mechanism to enable the watch-setting function. This is OK, but as with the similar analog clocks mentioned earlier, it is virtually impossible to set the time back by an hour and wind up with the minute- and second-hands set correctly. So my procedure on this is to wait until the second-hand is straight up, set the watch back 59 minutes, then watch an accurate clock until it is exactly on the minute, then press the setting mechanism back in to restart the watch.
OK - maybe that's a bit anal retentive, but since the watch itself is accurate to within a second or two per month, I see no reason to set it to anything other than the correct time.
Given 1 < x < y and x + y < 100.
Mathematician P knows the product x * y.
Mathematician S knows the sum x + y.
P: I can't determine x and y
S: I knew that.
P: Now I can.
S: So can I.
What are x and y?
I've posted a
solution in ruby.
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