User Interfaces and Usability for Embedded Systems

Feedback to "So This Button Must ..."- Murphy's Law, October 2001

Read the original artilce at So This Button Must...

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Bill Schmitt writes:

I'm betting you are getting an avalanche on this subject.  More often than not user interfaces on complex consumer products are either obscure or crippled.

The Ford radio in my 10-year-old Town Car remembers its volume setting if you turn it off while the ignition is still on, but if you just turn off the ignition, the radio comes on at the default volume setting.  Go figure - they built in a memory and then defeated it under a common pattern of use.  And yes, the keep-alive power is connected.  A power-sequencing device to defeat this "feature" is on my to-do list. And for some reason, the up/down tuning buttons are always in scan mode, so to tune you have to push a mode button first and tune quickly, because the radio quickly pops back into scan mode.

The same car and many others has the great/annoying feature of locking all the doors whenever you put it in gear.  Great for high-crime areas or a carload of rugrats, but endlessly annoying for the rest of us, because when you leave the car, all the doors except the driver's remain locked. It took an electrical manual and some time to find the right wire to cut. ......................................................................... ....

Bill Schmitt                           Digiserv, Inc.

Niallís reply:

Good points, though in fairness to Ford, they have put very simple radios in many of their new models, with just a few big buttons. They probably realised that most people just want to listen to a few channels, and those looking for loads of bells and whistles can go and buy a fancy one if they want. Apparently Ford have been paying attention to the large number of drivers who are over retirement age and are not as nimble fingered as the younger generation.


Spencer Shanson writes

Everything you said in this article is true. But just as you should be able to cut-and-paste text from a dialog window, you should never need to have to cut and paste a URL from a web page into a browser - it should always be a link. I'm talking about the reference to www.baddesigns.com in your article. I'll assume it was a typo :-)

As someone who had to ship a product with UI features I wasn't happy with, I can only tell you what I know. Mostly, these decisions are made by middle managers who are more concerned about missing their deadlines than in the later cost incurred in extra customer support or returned units. ie don't fret about the future dollars you can't see, but think about saving the pennies you can today. Stupid and short sighted in my opinion, and it always comes back to bite you.

Niall replies:

Fair point about the www.baddesigns.com link - I do not actually create the web page what becomes the article, though I thought that the ESP guys usually did put links in as appropriate.

As for the short sighted decisions, I am afraid you are not the only one who has seen these kind of problems. There are whole books written on cost-justifying usability work. I market a usability course to companies i the embedded area, and it generally gets zero interest, since companies simply do not see it as a priority

Thad Smith writes:

Dear Niall,

Last night I read you article (rant?) on user interfaces in ESP, describing the oven controls and the car radio.  Yes, I agree!  One of the step backwards when I got a newer car was the buttons-only interface, which is inferior to the volume and tuning knobs of the older model.  Recently my wife talked to our son, Joel, who is in college out of town, asking about using the cell phone which he left behind.  She was planning on using it, but didn't know how to answer a call when it rang!  She had been using an older analog cell phone for years.  I agree with your point -- let's keep the simple functions simple and obvious.

Your common sense articles remind me of Donald Norman's books of a few years ago.  Are you familiar with him?  He wrote similar stories about good and bad interfaces and designing for ease of use in general.

Keep spreading the word.  :-)

Thad Smith T3 Systems

Rich Cabot writes:


Great column on poor user interfaces in embedded systems.

A few points you may find useful.

A great book on your topic is called "the design of everyday things".

A notably bad human interface was the Ford Taurus radio/air conditioning/defroster/ and a few other things panel of a couple years ago.  It was oval shaped with all the buttons the same shape and placed in some indecipherable pattern.  Impossible to run without reading the labels every time.  I began refusing rental cars when they were Taurus's.  They changed it after two years.

Your reported problem of having to type in error messages.  Try CNTRL-C to copy the text and CNTRL-V to paste.  It works an amazing amount of the time, even when the software does not appear to allow copy and paste.


Richard C. Cabot, PhD Lake Oswego, OR

Danial Singer writes:

Mr Murphy,          

I enjoyed your oven comments - the mixed mode dial really does simplify the interface in an elegant way.

Presuming there are mechanisms which prevent the user from selecting between 200 and 0 and between Fan and 50, there is one character which makes your new dial misleading: the zero. When you set the oven at zero, it probably does not become a freezer. Some other symbol for "off" would be appropriate, as the zero has meaning in the thermal context but that is not how it is used in this case. Perhaps the international "no" -- the circle with slash -- or a simple X.

DBS --- Daniel B. Singer Nova Biomedical, Inc.

Niall replies:

Thanks for your comments - I had assumes that the dial clicked from place to place between fan and 50 - though I had not really considered between 0 and 200- but a click would be appropriate to stop someone thinking they could use the position in between to mean 100 or some thing silly like that.

Very good point about the 0. I realised that it was a little confusing, but I did not stop to think of an alternative symbol. "Off" would work fine in English, but the point of that part of the article was that the manufacturer had international needs and had to use an icon. O is often used for off and 1 for on, but if you also have a numerical range it becomes a mess - especially when the minimum value is not actually 0. Maybe a big dot would work for off - I think I have seen that on some dials.


Niall Murphy

Scott Neugroschl writes:

Then there's the applications that error, put up a dialog informing you of the fact, and then when you clear the dialog, immediately fault again, and put up the same dialog...

I once saw a "guideline for systems programmers" that read "Never test for an error condition you don't know how to handle."  Yes, it's funny, but there's a nugget of truth in there.  Do you tell the user, who probably has absolutely no idea of what to do about it?  Do you reboot/halt/panic?  Do you silently ignore it (usually a bad idea)?

I think that many design errors fall into that category.

In addition, others fall along the lines of your stereo TUN button.  People design for themselves.  In our industry, many things started out as, "I really need this for me," and others people see it and use it.  Sooner or later, someone without the requisite background will get confused.

Even Microsoft, with their vaunted usability labs has fallen prey to this sort of syndrome. I mean, does it really make sense to hit the "Start" button to shut down your system?

Short of mandating HCI classes for all computer science graduates (which won't work, as many developers don't have CS degrees!), I don't know what can be done about the state of affairs.

My opinions are my own and do not purport to reflect those of my employer.

Scott Neugroschl                

Troika Networks, Inc


Dave Muller writes


I enjoyed your column on user interface blunders ("So This Button Must...") and thought I'd pass along my pet peeve.  As a programmer for 25 years I've gotten pretty good at typing, so I can cruise along pretty well, usually looking at either a book or the keyboard.  And I can't begin to count how many times I've looked up to find that my last two sentences have been swallowed up by a pop-up window for a (usually trivial) error of some sort.  It annoys me immensely anytime the system steals the focus away from the program I'm using.

As for icons, I have long complained about the fact that instead of using an English word that some users will understand, companies now substitute an icon that no one can understand.  I've never been able to see that as progress.

Keep up the good work!

  --Dave Muller Comtech EF Data

Couldn't agree with you more regarding not being able to cut and paste text from windows error dialogs. (I'd paste in the exact relevant text but CMP's web interface prevents me from cutting and pasting text!)

Don Wade

Niall's Reply:

Fair point CPM's rendering mechanism is certianly not user-friendly in this sense, but I suspect that this is a deliberate attempt to avoid piracy of their product. Security and usability are rarely easy bedfellows- just consider how un-user friendly it is to have to enter passwords,

thanks for the feedback,
Niall Murphy


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