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Picture of Hipmunk Bathroom Status Indicator Sign
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I work at Hipmunk, an awesome hotel/flight search site based in San Francisco. To give a bit of background, until our subtenants move out, our current office has a single bathroom for more than 10 employees and nobody can see the bathroom door to see if it's in use, so there's a bit of lock contention.

The obvious solution is an airplane style bathroom sign.  So I made one at Techshop San Francisco, using only the laser cutter.
 
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Step 1: Front Design

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The design is based on this style of airplane bathroom sign, which I believe is standard on an Airbus A330.  Since we have a cute Hipmunk mascot, I had to include him.  And while two Hipmunks on the sign tilted each direction might be ultra cute, Hipmunk was founded by the same guy who made Reddit, and so the Reddit alien was an obvious choice for the second figure.

Using the picture as a reference, I traced the sink and mirror pattern from the original sign and the Hipmunk mascot, then found a vector version of the Reddit alien and assembled them all together into a 15"x8" rounded rectangle.

Step 2: Case Design

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I don't really know anything about bending acrylic, but I have glued some before.  For this sign, I just used a box made out of layers of 1/8 inch acrylic to create a space to fit all the LEDs and have the light bounce around a bit.  In the final version the layers are so, from front to back:

* white border around front to hold next layer
* single-side frosted clear (translucent acrylic causes the pattern to be too blurry), with opaque white border on three sides to hold this layer in place
* white with the pattern cut out
* mirror with the pattern cut out (this layer is not entirely necessary, since it only serves to reduce the light leakage through the layer before it)
* translucent white to diffuse the LED light, I believe it's 60% transmission
* about 8 layers forming the wall of the sign (one of these layers holds captive nuts for the screws that hold the back on)
* mirror acrylic
* white spacer layer
* white layer with wall-mounting holes

it may be possible to sand the sides flat, but I like the rough layered look, so I left it as-is.

The layers are almost all glued together with acrylic glue, except for a gap before the last mirror layer, which is so the back of the sign can be removed.

Step 3: Electronics

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The circuit is about as basic as possible. There are no arduinos here.  Just a relay with a resistor, a magnetic door switch, and LEDs.

* relay: 653-G6RN-1-DC5
* 100 ohm resistors: 293-110-RC
* green LEDs: 941-C503BGCNCY0C0792
* red LEDs: 941-C503BRCNCW0Z0AA2 
* copper wire
* magnetic door sensor (self adhesive!)
* stereo cable, 1/4 inch stereo plugs and sockets, and project box from radioshack
* 5V, 2.5A DC power adapter I found in my room

The box contains a relay and a resistor to limit current through the door switch, it then switches the 5V power supply to one of the two conductors in the audio cable.  I used the copper shield of the audio cable as a ground and the return path for the current from the sign.

I used a piece of acrylic with lots of holes lasered out to hold all my LEDs (about 11 of each color).  The copper wire acts like a bus bar powering the LEDs, one for each color, then a common ground connection.

Step 4: Assembly Test

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After cutting out all the layers, I assembled a strip of LEDs (actually used some acrylic perfboard I made to fit in the sign), and tried it without gluing anything to see how well it worked.

Note that there is not really enough diffusion with just the top strip of LEDs.  I added a strip of frosted acrylic over the strip of LEDs inside the sign to diffuse the light.  I also made cutouts of the hipmunk and reddit alien from 60% transparent white acrylic that I placed under the frosted cover layer to further increase the light diffusion.

If I made another sign I would use more LEDs and diffuse the light a lot more.

Step 5: Installation

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I installed two screws into the wall spaced 8" apart, then hung the sign above this sort of doorway/staircase thing.  The wire runs into the "server closet" under the stairs, into the relay box, which then has a cable that runs to the bathroom door around the corner.

It works pretty well since people would already leave the bathroom door open when not in use.  I got lucky with estimating the wire lengths so I didn't end up having to splice any wires together.

Besides the reportedly amazing productivity benefits, it was a a fun project and, as always, the laser cutters are like making things on ez-mode.
I love this thing and you picked great designs! You should enter this into the Father's Day Challenge that is ending tonight at midnight!
Thanks! I'm afraid this isn't for anyone's father though :(
lmbarber3593 years ago
This looks aweson
awesome
mh76dk3 years ago
This reads like one big advertisment to me :-( from the "i work at..." right down to the amazon links with (i presume) your referer.

You may have meant it as a guide, but to me only all the brandname- and link- dropping stands out :-(

I only hope I am wrong
christopherhesse (author)  mh76dk3 years ago
Haha, I receive no compensation for those links, but I will remove them if it gives that impression.
Its hard to judge intentions over the internet. And i admittedly jumped to conclusions regarding the "ref" part of the link - are you saying they are not referer-payment links, or are you just saying you don't make any money because nobody clicks them? (i am sure you can see which one i find a bad excuse ;-)

Either way, I did not mark it as spam or anything since it did look like an honest to god guide. Instead i decided to post my opinion, take away what you want or ignore me :-)
christopherhesse (author)  mh76dk3 years ago
np, a private message might have sufficed here though. I mention the names of places I buy materials from and the part numbers whenever possible because I like it when other people do it. It makes it easy to get my own and not accidentally buy the wrong items.

I investigated the ref= Amazon link you were referring to, they apparently were "ref=oh_details", which appers to be generated when you copy the link from your "order history details". Good to know they make suspicious links though, thanks for the heads up. Mouser does not have a link affiliate program that I am aware of.
a private message would have been a waste of time had you actually been spamming :-) a public one means other visitors get to make up their own mind (and possibly correct me)

i am perfectly willing to admit that i'm likely one of the more anal anti-ad people around here (if i had my way, linking to your own blog in an instructable is spam, unless there is a really good requirement for the link - we all get the "homepage" box where we can put such a link) and your "offense" was even in my book very light (hence only a post and i tried to be extra civil in it too :-)

Good thing its all sorted though, and just so you know, most other people here are a lot less annoying than me, so don't let me scare you away ;-)


gmjhowe mh76dk3 years ago
Honestly? As long as there is a full instructable, and you can download the files and it is something people can learn from. Then you can drop you links as often as you like.
mh76dk gmjhowe3 years ago
two minor issues while I do agree with your overall sentiment;

1) If it looks like an advertising off the bat, people might not look any further and the post does not get its otherwise deserved attention

2) the referer links i believe are against the site rules, and there is no mention that following them could make money for the poster

This post just really stood out to me (but yes, I might hate advertising and self-promoting people more than average, I do however try to point it out nicely when it does not look intentional :-)
This is a great idea. Love it. :D