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MindWave Cat Ears

by joshd, published

MindWave Cat Ears by joshd Nov 11, 2011

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BSD License
MindWave Cat Ears by joshd is licensed under the BSD License license.

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Some time ago, a friend of mine asked me to make her a pair of mind-controlled cat ears, and I said, "Oh sure! I can do that."

In my defense, I'd had a bit to drink that night, and didn't think she was serious.

She was.

(Oh, dear.)

On sober reflection, I became curious about whether I could do it. All the pieces seemed to be present:

  • The Neurosky headset had just been featured in Make Magazine.

  • The arduino microcontroller makes doing simple robotics like this relatively easy.

  • The Makerbot and reprap printers make it possible to iteratively design custom hardware, which was going to be really important.

So instead of completely and utterly insane, the idea turned out to be merely odd. But doable.

Anyway, if you've ever woken up and said to yourself, "I'd like to strap a pair of robotic cat ears to my head, and interface them with my brainwaves," your wish has now come true.

Prototype 1

The first prototype is complete. It's imperfect, a bit fiddly, and bulky, but it held up long enough for us to put it on and walk around downtown Boston with it.

Here's a video of the first prototype in action. It showcases the ears drooping, standing upright, and wiggling at different levels of mental activity:


Who should make this?

Let's be honest, this is a lot of work to do in order to make some kitty ears. The purpose of this thing was to learn how to do it and have fun. And I'm releasing it here because I'm curious what else people could make based on it.

Make Something Different

I'm very interested to see what can be made with this toolkit beyond cat ears.

The servo mounts can be used to attach motors to the MindWave headset, which was a bit of a tricky mechanical problem. Now that that's solved, what else could you do? Some suggestions for things you could make to mount on your head:

  • other ears, like dog or rabbit ears

  • antennae

  • spikes

  • fricking laser beams

It's hard to make derivatives of .STL files, so I'll be uploading the Solidworks files for people to tinker with, as soon as I have a chance to clean them up a bit.

Special Thanks

Many people helped me bring this project to completion. Some tried (vainly) to maintain my sanity. Others helped by listening to me rant like a madman (and didn't back away quickly enough). Some others contributed directly, and I'd like to thank them here.

Miriam Byroade designed and sewed the fabric for the ears and the holster holding the electronics.

Jeff Cutler contributed significantly to the arduino code, and is single-handedly responsible for the MoveToPosition(); function.

Amber Ying dared me to make the ears, modeled them, and has patiently tested three versions of them, all the while waiting for a working set.

Thanks again to all of you, and to the others I haven't mentioned. I promise to bother you more as I work on the next prototype.


In the near future I promise to put together a full set of instructions for printing, assembling, programming, tuning, and testing the ears. For now however, here's a very rough overview:

  1. Print all the .stl parts

  2. Mount the servos and ears on the headset

  3. Connect the ears to an arduino and tune the movement and behavior

  4. Connect the MindWave headset to the arduino

  5. Mount and route the wires and components, and make it wearable

Printing the servo horns shouldn't be difficult. I made them with a stock MakerBot Cupcake with a MK6+ Plastruder, using 3mm filament. (The ears, however, can be tricky. I printed them with no extra shells and with support material, on a really really big chunky raft. The ear shells themselves are almost certainly getting a redesign as soon as possible.)

I'm still taking assembly pictures, which should help a bit.

I've created a github repository for the arduino source code, and will maintain the code there:


Roughly speaking, you'll want to hook the servos up to their own 4-AA battery pack, bridge the ground to the arduino, and plug the control lines into pins 3,4,5, and 6.

Then you get to tune the "minimum" and "maximum" values for the servos, which will vary depending on exactly how you position them.

Once those are set, you get to make the arduino talk to your MindWave headset, which is documented on the NeuroSky website. I have some issues with their documentation, and will supplement it later.

But once that's done, you should be able to control the ears by putting the headset on. There will be a big mess of electronics next to you on your bench, though.

The final step is to make the whole thing portable. I'm still refining this part of it: the first prototype uses a board with "european-style" screw terminals and a ribbon cable running to a protoboard holding an arduino nano, the MindWave wireless adapter, and some batteries.

That's All, Folks

These instructions are inadequate and incomplete, but watch this space for updates. I'm happy to answer questions or concerns in the comments.

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Necomimi do exist, and cost significantly cheaper than a standard mindwave headset.

They certainly do… now.
They didn't when this project was completed and posted.

Wow this looks amazing! I am working on a school project where we get the chance to print from a 3D printer. My teacher agreed on my plan to make these cat ears from your website. It will be mostly about the design rather than the programming, BUT I just can't figure out how to put the ears together with the other plastic mechanism. As in, where should the rear and front be opposed to the ear itself? I hope you can help me because printing day is coming closer and I want to be sure this will work :). Thanks in advance!

Hi, Folthan!

There are many other components to this project besides the printed ones, and assembly is rather unfortunately complicated and time-consuming. It takes me about 48 hours to assemble the full ears with wiring, and I designed the things. :)

I hope to improve the design significantly in the future. For now, however, I advise caution: this may be more than you want to take on.

This is AMAZING. I wish i had some but they look really uncomfortable.

They are comfortable enough to wear for about five hours without irritation. And that's the maximum length of the battery, so it's the design goal I set for wearability.

thx for the ellaboration

Okay, my 9yr old son wants these for Halloween.  This is why I love Thingiverse; you find out just how many (or few) people out there think like you.   Any changes since you posted this that we should be aware of before digging in?

The tail Thing http://www.thingiverse.com/thing:13522http://www.thingiverse.com/thi... and this...

have all the electronics wired to the base of the tail aka a reversed bumbag/fannypack.

You could review hiden personal mic/ear wig setups for ideal setups with power weight distributions and cord designs.

This might be the start of thought activated costumes/armor etc. A real and lol wothy application of the Neurosky headset.

Animatronic Tail.

Apparently, TIME magazine selected Neurowear's version as one of the top 50 inventions of the year: http://neurowear.com/?p=153http://neurowear.com/?p=153

So I think you can consider your cat ears to share in the honor :). Congrats!! Of course, yours will always be the original in my eyes.

If... I recall, Neurowave is already doing something quite similar to this product. In fact, it's the exact same product. It's from Japan, and they have both a black and a white style. They've had it demoed in France as well.



Be careful, these folks may try to sue yeh ;)

Incredible. I don't think it's a long step between mind controlled cat ears and mind controlled prosthetics. You may really have something important.

I wonder about how much the productin cost on this is? $99 for NeuroSky + ???

That's a very good question. To be honest, I'm really not sure how much it costs to make a single set of these: I've made dozens of small tests, fried a bunch of electronic components, and bought the wrong stuff more than once.

I'm currently outlining the steps for a full build, and will be making a new set of ears from scratch. Then I'll be able to give an estimate on the cost to make it.

Sweet man. Thanks for sharing these designs. The girls are gonna love this. =-X

Id do anything for a pair of black moving cat ears! A moving tail doesnt bother me so much although that would be cool too!

I wonder what the asking price is? I want one!

Can anybody make me one
lt; I'll buy it from them, well depending on how much it is o.o;;; And if it is possible a movable tail would be awesome

I have a mindset I can probably help with the coding. Oh and a robotic tail you could grab stuff with would be awsome...

I'd love the help, thanks!

And I'm working on a tail too, actually. It won't grab things, though. Just swish.

You could make it respond to the wearer's emotions just like the ears. You know, wag for happy, curl under for fear, just like a dog.

These are super cool. Thingiverse might not be up to the rigors of documenting such an epic project. Have you considered a companion Instructable? I bet you make it into the newsletter with this one.

I'm certainly considering a companion instructable. Or, I may put together an instructional video or PDF. Still working on it. Thanks!

P.S. that's my 1inch square Ardunio clone I am holding there. Perfect for a project like yours, if I say so myself. You can see how to make your own here: http://www.instructables.com/id/Make-your-own-1x1-22-IO-pin-Ardunio-Compatible/http://www.instructables.com/i...

That's a very impressive Arduino clone! I'm not certain I'm up for surface mount soldering just yet, but my hat is off to you.

I tried prototyping the ears using an Arduino Pro Mini, but the one I had was only 8MHz, which turned out to be too slow to handle the data from the MindWave headset. The arduino nano is small enough for me at the moment, now that I've made some design changes to reduce the electronics footprint f
or the next prototype.

Fun project! Nice work!

Thanks! It was fun. I'm working on version 2 now, because why not?


Not the most useful thing ever made, but how could you not keep working on it. :)