3D Printed Motorized Bathroom Sign




Introduction: 3D Printed Motorized Bathroom Sign

About: Robb was once an Artist-in-Residence at Autodesk's Pier 9. He went to Carnegie Mellon to study Art. He mostly does tangible artifacts that are often complex. He can be reached at www.robb.cc

I made a 3D printed motorized toilet sign that changes from pants to a dress every 15 seconds. It is free to make and modify.

Bathrooms are complicated business. In the USA, recent transphobic legislation has tried to delegitimize the basic need of trans folk to use a bathroom. Many progressive institutions have thankfully responded by systematically de-gendering their toilet facilities. Here is a sign that might help in such an effort. My sign acknowledges the absurdity of the traditional signs, which fail to recognize that:

  • There more than two genders (Discussion)
  • That women can wear pants, and men can wear dresses.
  • That gender is not related disposal of excrement

A future without gendered bathrooms is is future where all people wait the same amount to time for the bathroom. it is a future where no one is afraid to pee because of who they are. and thankfully, It is a future we seem to be heading towards.

This is a political project. If you don't think politics have a place in making, you are mistaken. Also, the comment section is no place for hate. Keep it calm, keep it kind.

Further Reading

Unpacking the Public Bathroom Debate for Cis People: Why Bathroom Access Needs to Be Safe for People of All Genders

Why Bathrooms Should All Be Gender-Neutral

Step 1: Mechanical Design

This design uses a simple crank mechanism that drives the left arm. The left arm has a slot that the crank pin rides in. As the crank spins, it opens the arm in a sine-motion, called harmonic motion. This is ideal as it is smooth and gives both states (pants and dress) equal time. It is also easy to make from a spinning input.

The right arm mirrors the left arm's motion using a simple 1:1 gear system. Both gears are only partial, due to aesthetics and the limited 16° motion of both arms. The gears are centered on the axis of rotation. I used the Gear Generator Script in Fusion 360. It required some math.

Another option would have been some kind of balanced dual pendulum design with electromagnetic impulses from a coil to keep the motion going. This is how the waving cats and other solar powered toys work, but I am not sure I have the engineering chops to make it work. Maybe next time!

Solar Toys Further Reading

Step 2: CAD

This is a tricky thing to design. It is essentially 50% mechanical engineering and 50% graphic design. Not so many tools are good at both things.

I started with the AIGA Symbol signs (Helvetica Woman + Man)I started this project 4 years ago the 2D vector program Adobe Illustrator. This sucked, as I had to print out the design and test in paper each time I wanted it to move.

I eventually tried it in Rhino3D but was frustrated by the lack of mechanical features.

I then moved to Autodesk Inventor, but it is very constricting and difficult to use.

Last week, I exported each part as a 2D DXF file and rebuilt it in Fusion 360. Fusion is free for makers and enthusiasts like you and me. It has mechanical joint support and a friendly (By CAD standards :-) interface.

Here is a video of the last few steps of my design. It is not narrated.

Here is the online version of the CAD which you are free to remix for any not-evil purpose, even if you want to sell these things. Go for it.

Want to learn more? JON-O-TRON has the best mechanical Fusion360 projects I have seen.

Step 3: Find Your Motor

Adding the motor

I used a low-rpm AC microwave oven turntable motor. These are free in broken microwaves or cheap online. They are simply plugged into the wall with no control circuitry needed. They use AC voltage, so very careful as this can hurt.

I was very lucky to find a 3D model of the motor I found. I think these motors are very standardized.
Special thanks to Marco Gregorio on GrabCad for this Microwave Turntable Motor model, and for the sweet GIF above.
Make sure it has the D-shaped shaft and the voltage of your country.(110VAC or 220VAC) The low voltage AC models need an expensive transformer.
If you find an old microwave, look at the bottom. The motor can often be easily removed with a screwdriver.
220V model
110V model
You can also use a servo if you modify the design.
I dream of making a solar-powered version to avoid the wiring hassle. Something like the toy cats that wave forever.

Step 4: 3D Printing

Here is a link to the Thingiverse page.

I printed with no support, no raft, no brim on a FDM machine. It took about 8 hours.

There are many file types on the thingiverse, feel free to remix!

Keep in mind that layer-to-layer adhesion needs to be good because the two arms rotate on very fragile pins. It might be worth using small screws with nylon lock-nuts if you experience difficulty.

Step 5: Adding Crank Wheel Pin

The crank needs a metal pin to function.

  1. Find a very small nail or a regular paper clip, about 1mm in diameter
  2. If paperclip, Straighten out the paperclip for a 20mm section (3/4"in.)
  3. Holding the clip with pliers, heat it over a flame or a stove.
  4. Press it into the crank wheel, in the small hole. (it is near the flat side of the D-shape)
  5. Leave 3-5mm (0.1"-0.2" in) protruding through the front face
  6. Allow to cool, ensure it is straight.
  7. Trim excess on back or front if needed.

Step 6: Attaching Arms

The two arms are snap-fit into the armpit joints. Ensure the arms are in symmetrical positions before snapping in the second one. Try to avoid removing them, as the pins are super fragile.

I used sandpaper and the edge of a sharp knife to clean the parts before assembly to prevent snags. Keep in mind these pins are extremely weak, and may even be too weak to work if your printer is not calibrated. Small screws and nylon lock nuts would be better, but require drilling or modeling two holes in the arms.

Test the motion. The arms should move symmetrically.

Step 7: Adding Crank Wheel and Motor

The crank wheel with its new metal pin should simply press fit onto the motor shaft. The shaft-hole is slightly tapered for a snug fit.

The motor can now be mounted on the mounting boss with one or both Metric M4 machine screws. Adjust the arms until the pin lines up with the slot in the left arm.

The whole thing can now be hung from the column on the back of the head.

Step 8: Electrical Assembly

WARNING- AC voltages can kill you. Be careful. Use insulated connectors.

  1. Find a wire or an extension cord that has a good color and length
  2. cut the socket end off
  3. strip back the first layer of insulation about 25mm (1")
  4. Strip each wire about 4mm (0.2")
  5. Crimp a pair of insulated spade terminals onto the wires, and press them onto the terminals of the motor
  6. You can also solder, but be sure to use heat-shrink tube to protect curious fingers from painful shocks.
  7. Plug it in, and watch it spin! It is only 4RPM so be patient. :-)

You are done! Enjoy! Post photos in the comments if you make it!



    • Water Contest

      Water Contest
    • Creative Misuse Contest

      Creative Misuse Contest
    • Metalworking Contest

      Metalworking Contest

    25 Discussions

    I know this will upset some of you, but in reality there are only 2 human genders*, male and female. People are confusing gender with sexual identity.

    Gender is a scientific term and as such is not mutable, it has one true definition only. Saying you belong to a 3rd gender is like saying you're a reptile. You might identify with reptiles but you're still a human being, this isn't something you can change.

    *intersex (also known by the old term hermaphrodite) while sharing characteristics of both genders are not in themselves a different or separate gender.

    I have no problem with people identifying themselves as having a different orientation and/or sexual identity, I support them in doing so, but I also believe that they should be accurate in their terminology so as to avoid confusion.

    Beyond that, good instructable,

    4 replies

    Hi DropKick! I'm glad you like my 'ible. I am glad it is stirring up the critical discourse it is intended to provoke! It is a very nuanced subject.


    To echo what SiouxsinT expressed, gender is of course a scientific term, but it is not a synonym for sex as you describe. Gender and sex are often correlated, but the relationship is complex. The word Gender only existed in linguistics for latin/Spanish/German/etc nouns until the 1950s(!) when it was intentionally introduced as a way to talk about the (scientific) differences between sex and the socialized behaviors associated with 'man' and 'woman'. A simplified explanation is that male and female are sexes, while man and woman are genders. Almost all animals and many plants have a sex, but gender exists only within social animals with societies.

    Intersex persons have genital features from both sexes, nothing to do with gender at all.

    Most importantly, I feel that your insistence that people should "be accurate in their terminology so as to avoid confusion." is hurtful to people who are not cisgendered. A cisgendered person has gender identity that society considers appropriate for their sex. I find your comparison of the very serious plight of non-cis persons to reptiles very distasteful, to say the least.

    In my time a non-genderd bathroom, was just called a bathroom. But yeah that would just be over-simplifying, no?

    Actually gender is a social construct. You're confusing gender and sex. Sex is biological (and still not binary for the reasons you mentioned), gender is sociological. We developed, and modified, the concept of gender ourselves over the last couple of million years.

    I did exactly what I was accusing others of and defined a term wrongly. Sorry.

    However, even though I was wrong and the term gender isn't a scientific term I still believe that it is being used incorrectly - I could be wrong in this also though. It will require more research on my part.

    Once again I apologize.


    I don't see where the use of correct grammar would be hurtful to anyone unless they were just looking for any excuse to be offended.

    Also, I did not compare non-cis people with reptiles, I was comparing the misuse of grammatical terms in 2 different groups of people, neither of which were the non-cis as a whole.

    It does make me sad that you feel that those people who identify with reptiles to be distasteful, and somehow less, but no one is completely free of bigotry and we all should make some allowances for that.

    I love this idea!! and Yay for non-genderd bathrooms!

    You know, when I saw this Instructable, I thought, "Hey, an interesting thing the guy's probably using as a prank. But I'm going to see what it's about." And... I read the intro... Really? I thought that Instructables was a (for the sake of irony) safe space, where all this gender nonsense wasn't going to be a thing... I mean, it's a clever design, don't get me wrong, but... why bring that here?

    2 replies

    Hi Jeff! I am glad you think I am clever.

    Instructables is a safe space in every way possible. It is made safe by a team of dedicated moderators, developers, and community members. I have had the privilege of working for Instructables at their SF office with the lovely, open-minded, and diverse team there. I assure you that the instructables space is safe, suitable, and appropriate for gender nonsense of all kinds. I think you will find as time wears on that this 'gender nonsense' will make more and more sense to larger swathes of society, as LGBTQIA... people and those who love them are everywhere and this sort of nonsense is exactly the nonsense that keeps us up at night.

    First off, I must apologize for how I said what I did, and I appreciate your mature response to me. But I simply just don't agree with your opinion, and don't wish to continue this discussion here (if you wish to contact me, message me). Also I'm not saying that the people who believe this is right aren't otherwise good people, It's just that morally I don't believe this was a good turn for society.

    Really beautiful project, i love the idea. Is just Art!

    But level that printer bed ... that first layers looks terrible :P

    1 reply

    I know, right?! I was shocked in the morning when the print hadn't failed. I didn't have time to tune the printer, and i was borrowing it from a friend.

    I'm glad you like it!

    Cis, trans, it's all greek to me. I just figured that people got tired of hearing boys giggle at the word sex, so they started using gender instead. Growing up the terms were always interchangeable. Speaking of which, I think you should make a version 2.0 with the Monty Python The Flasher:

    I love this instructable for both the ingenuity of the design and the message.

    Really impressive! Thanks for doing this!


    1 year ago

    I could see this engendering a bit of unhappiness in some folks, but I think it's genius.

    Nice to see how you solved the kinematics. As always, you give good Intructable. My only nit is, it's still binary or rather transitions between the normative binary.

    1 reply

    Hey Paolo! The way I see it, it is more of a parody of the traditional sign. The best sign for a toilet is a picture of a toilet. :-)

    I love it! Better than the longitudinal "half-pants / half-skirt" in that it is not permanently split in half and shows a sense of change :)

    2 replies

    I'm glad you like it! I agree, The half-half sign is very confusing. The best sign I have seen is a just picture of a toilet.


    Hahahaha this made my day, so simple and efficient. Talk about thinking outside the box

    Very nice! :) Might build some of the solar version too for the SHA2017 festival in the Netherlands. There's many people who will love it. Thanks!