
Great design: The airplane bathroom lock and light switch - drm237
http://www.37signals.com/svn/posts/936-great-design-the-airplane-bathroom-lock-and-light-switch
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mynameishere
You know what else has a great design on a plane? The turbofan engines. In
fact, give me a blueprint for a 757 and I can probably find 50,000 things with
better design than the bathroom lock. I have a special fondness for the RAT:

<http://en.wikipedia.org/wiki/Ram_air_turbine>

and if I had to choose between the bathroom lock and this set of technologies,

<http://en.wikipedia.org/wiki/Ice_protection_system>

...well, I just don't know. But no one adores the trivial like 37signals. Of
course, you say, "They are focusing on user-centric design." Well...in that
case, the door-light combination doesn't seem as good as a motion-detector-
door-light combination, which would turn ON with motion, stay on when LOCKED,
and turn off when UNLOCKED. That didn't take an engineering degree to come up
with. Where's my kudos?

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easyfrag
You're introducing unnecessary complexity into the system; instead of the
lock, light, and wiring between the two we would have lock, light, motion
detector, and wiring between all three. It may be trivial, but ensuring fewer
failure points is good design, especially at 30 000 feet.

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edw519
Don't forget the bright blue light (on Southwest anyway) that turns on by the
flight deck door to let everyone else know the front lavatory is occupied.
This is to prevent a line forming (in violation of TSA regulations).

Now that's what I call extensible.

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timr
The comments are better than the article -- as one notes, the design is
terrible if you're not inclined to step into a tiny, dark room and lock a door
behind you (e.g. a toddler who is afraid of the dark). I'm not a cranky
toddler, but I've thought that this arrangement was a bit goofy, myself.

My feeling is that a better design would use a motion detector to activate the
lights. The combination door lock/light switch design doesn't seem to do much
of anything, other than make the door more complicated and expensive.

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anupamkapoor
> a better design would use a motion detector to activate the lights

but the amount of space available for movement is too small. probably too
small to detect with a motion detector ?

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derefr
Don't bother detecting motion in the _space_ in the room--just attach an
accelerometer to the door. It's not going to be touched unless someone's
coming in, and they'll usually _start_ to close it before they step inside.
That is, if it is closed by default. Open by default might be harder.

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mhb
So when the maintenance people clean the lavatories, do they bring their
equipment in and lock the door so they can see or do they cart around their
own lights so they can leave the door open and have enough room to work? Or is
there an override switch somewhere?

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naxxtor
If anything, this article demonstrates the great design of reader comments -
almost all of them disagree with the OP and make better reading than the
original post!

Hurray for blog comments!

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earle
yeah, but you can barely find the lock in the fist place because its small,
and unlabeled. I dont know if this is great design!

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kirubakaran
Do you like it this way? :-)
[http://photos1.blogger.com/blogger2/1715/1669/1600/larson-
oc...](http://photos1.blogger.com/blogger2/1715/1669/1600/larson-oct-1987.gif)

