Picture of Animatronic Tentacles with Arduino

***Disclaimer***This instructable is documentation for a work in progress. Although the project is not yet complete, it has reached a place where I believe it can begin to be beneficial to other makers.

The concept for this project was spawned when a friend suggested I be Slenderman for Halloween. When I first looked at pictures, I wasn't terribly excited because I am a prop builder more than a costumer, and Slenderman didn't have any props. However, I then discovered that in some depictions he has tentacle-like appendages emerging from his back. I started scouring the internet, seeing if anyone could give me any advice on how to bring this part of the costume to life. To my dismay, the best I could find was suggestions using armature wire to support the tentacles, but they wouldn't move so I set out to design my own.

The Overall Plan:

-Include 4 or 6 Tentacles

-Be mounted on the back

-Be controlled with 1 or 2 Arduino's using 2 Wii Nunchucks

-Move automatically when not being actively puppeteered

-Have an option to fold tight for moving around tight spaces

UPDATE 2/24/15: Hey Everyone, I am thrilled by the support this project has been getting since I released it just over 2 years ago. I have to say that unfortunately, monetary constraints (being a poor highschool student turning into an even poorer college student) and time constraints have put this project on the back burner for the majority of the last 2 years. I haven't forgotten about you guys, and I am looking forward to delving back into this project soon, hopefully. Don't think I haven't been learning though, in the time away from this project I have picked up numerous skills that I can see applied in hugely useful ways to this project in the future.

These include:

-Learning to machine parts by hand on a vertical mill and metal lathe

-Learned how to use a vacuum form

-Learned a LOT more about servo motors, and what I might need for this project

-Did research on Snake Robots (kind of like tentacles, right?) at the Biorobotics Lab at Carnegie Mellon)

-Learning how to use, and gaining some access to a Waterjet cutter (through Techshop)

-Taking a Class in theatrical casting and mold making at my University

-Beginning to pursue a degree in technical theater

Along with these things, I am also currently taking classes in Welding, Advanced Fabrication Techniques, and Embedded Computing (Arduino-based gadget building) at my University

Thanks for all the continued support, I will do my best to continue to answer any and all questions that come my way in the comments and my inbox. I hope that the next update I post here will be much more timely, and much more full of actual content.



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jhall302 years ago
Great project! I would suggest a couple of things, though.

1. Instead of two Arduinos, consider using just the ATmega chips, as they are far less expensive, and use the same command set (you can buy them with the Arduino boot loader already on them). I use an Arduino to program the ATmega and ATtiny chips, which greatly reduces the cost of projects.

2. I would try to add more random looking ambient movement to the tentacles. Use a defined range, and slowly transition between two random points within that range for each servo on a tentacle. For fun, randomly choose a delay time, as well, so that some tendons stay in their positions for longer than others. Make sure that this is also constrained to a reasonable range.

I love the work you've done, and the ideas you've come up with!

Think of fabrics for the skin. There are many options that are rubbery in appearance, and they'll cost less than silicone. They may weigh less, too.
thejuggler (author)  jhall302 years ago
Thanks for the great response jhall30! Now to my replies:
1. I have looked at this, and for the final version I think I might. I am also working on an Arduino Segway at the moment (Instructable to follow), which might be able to use the same idea. I have seen tutorials on how to program the ATtiny with an Arduino, but not an ATmega. If you have any resources on doing that I would love them, thanks :D

2. OOOooo. That's cool! I like that better than just sweeping between the extremes! Thanks for the Idea!

As for the fabric, I've looked at it but my sewing ability is near 0. Though swimsuit type material is starting to sound better after the fiasco of making the test skin. (My dad wasn't too happy with the mess I made in the garage)

Thanks Again!
sorry to ruin any visions of having the first ghetto arduino segway but johndavid400 already made one and its in his book. on the other hand you could just buy his book, follow all or some of the instructions and end with a segway. either way good luck and even if you just follow the instructions, the site could use another organized thoughtful instuctable like this one.
thejuggler (author)  awesaomeness51 year ago

Hi Awesaomness5,

I make no claims to my Segway being the first, there are dozens of them on the internet and I have drawn heavily from the information they learned and shared while building their projects.


1. You can use an Arduino itself to program your ATmega328p chip, and then pop it out and put in another. It already has the socket for it, unless you're using the SMD version. After all, that's the chip it comes with. If you get them online with the bootloaders already installed, they're plug-and-play in the board. The chips are around $2-3 online through some retailers. It's almost not even worth looking at the ATtiny chips, unless you really want to save space.

2. Yeah, I've had some luck with that technique in some projects. It keeps things reasonable while appearing random. I usually pick a base, then add a random number to it (which has been mapped to my "reasonable" range). I suppose you could just map the number directly to the range without the addition.

3. Sewing shouldn't be that difficult. It'll mostly be a straight line up until the end of the tentacle. Just sew it inside-out, and then invert it and slide it on the tentacle. Get a friend to help if you have a sewing whiz around. I'm lazy, of course, so I use a laser to cut fabric.

This is a frackin fantastic project. It looks amazing. I wish I understood more of the robotics part of it as I am trying to do something a bit similar for an Ursula costume. I would love to have tentacles that move on their own..

You might try neoprene for the skin. its fairly thick, but still is able to stretch and move. Plus, since its used to make wet suits, its obviously durrable.

danielepoi10 months ago

Hi. GREAT TUTORIAL! Well explained and interesting subject. I am trying to make a tentacle of sorts but i'm not sure about how you joined the servo motors to the cable. Do you have an photo or graph for that? It would be very helpful if you could publish one. thanks heaps!


thejuggler (author)  danielepoi6 months ago

Hi Danielepoi,

The reason I didn't post anything about that is because I haven't gotten it to work yet. I don't have a servo strong enough to drive the motor. My plan is to attach the cable to some sort of drum, however. Maybe something like a tiny winch?

Good Luck!

Drake231210 months ago

Hey i was wondering, would you be able to do what you are doing with the wii nun-chucks with an EEG device? if your not sure well that's ok but if you think it's possible could you message cause i plan on doing this and wearing it at one of my schools carnivals on my last year there, thanks for any info

thejuggler (author)  Drake23126 months ago

I think it would definitely be possible, though I personally have very little experience with EEG devices. Checkout Backyard Brains and the Myo armband though, they might be able to help.

So... When is someone going to say that the tentacles make you look like Nergal Junior?

jaybo20992 years ago
Pull some women's panty hose over the device for a skin. Then coat the panty hose with layers of liquid latex. You can also use pieces of tissue paper and unrolled cotton balls with the latex and build up different textures on the device.
thejuggler (author)  jaybo20992 years ago
That is an interesting idea, I have never worked with liquid latex so it would be a learning experience. But, then again, so has this entire project.

It's super easy. You can add a touch of acrylic paint to color it and you simply paint it on in thin coats. You end up with a great rubber surface that won't crack. At $55/gallon it isn't as bad as silicone either.

looop4511 months ago

Give us an update. Even if it is a small one.

Hey just wanted to ask.... How much did this cost? I want to do this for squid girl!
Darkfur2 years ago
Nice, now I have a hardware guide to go with my software!
thejuggler (author)  Darkfur1 year ago

You had software lying around for this?! I'd love to get a look at it sometime if you wouldn't mind.

I can dig it up if you want...
thejuggler (author)  Darkfur1 year ago

That would be great. Why do you have software for this?

I intended to build a backpack for a slender man costume for halloween, complete with pseudorandom flailing tentacles. Though I never got around to it.

shadowopal1 year ago
Howdy. Been following this for a while and am curious how the project is coming. Going to start using your project for 2014 Halloween.
thejuggler (author)  shadowopal1 year ago

Hi shadowopal,

The product has been put on hold for a while for budgetary and time concerns. I ran out of money to invest in it (poor college student) and I entered college. I hope to pick the project back up when I get the chance and will update this page as soon as the project get's back underway. Good luck with your build!

Juggler, maybe we can help each other. My biggest challenge will be acquiring the vertebra and creating a backpack mount as I don't have access to a shop or 3d printer.

If you are able to assist me with that, PM me and let me know how much of a gift$ you would like (beforehand) in exchange.

Thank you so much for this. This is inspiring. I just purchased the Stan Winston Tentacles video and am going to watch this and start planning for Halloween 2014.

If you had to provide a very rough guestimate of how much the tentacle setup will cost (per your design here), what would that be? $50, $300, $1000, $5000? Again, I know there are a number of variables regarding cost, but I'm just wondering what I'm considering getting myself into. Cheers!

JoCu641 year ago
Fascinating project - re skin material how about this LDPE tube netting http://www.componentforce.co.uk/category/413/protective-netting-high-stretch. Commonly used to package & protect delicate items like bottles etc. Should be light, stretchable and add a bit of texture. May also be possible to fit over a tapered former and dipped into liquid rubber to fill voids.
thejuggler (author)  JoCu641 year ago

Neat Stuff! I will take a look at it. Early on I considered the jacketing stuff they use to make large cable snakes. (Sorry if that doesn't make since, I don't remember what it was called) This product looks simpler and more flexible.

mmontemor1 year ago

I have laughable experience on arduino builds on general but could you clarify some doubts? I intend to build something very similar to this project of yours, but with a tougher structure that can, at least I hope, serve as an automated arm to hold things and stuff. Yeah, Dr. Octopus style.
Do you think I could do it just by adjusting your build? New materials and stuff.

thejuggler (author)  mmontemor1 year ago

The Arduino is a pretty powerful platform, and I have yet to be disappointed by what it can do. To drive a robotic arm of that strength you will probably need to beef up the circuitry with an external power-supply and something like an H-Bridge to drive the motors. I'd love to see how your project works out!

mae-kitty2 years ago
What is that black joint piece you are using? Did you create it or buy it? If so where from?
thejuggler (author)  mae-kitty2 years ago
It is a Cord Grip Strain Relief Connector. I bought it, I don't have the URL handy but I will look it up and add it. It's designed use is to waterproof electronics enclosures and to hang cords from ceilings. They are commonly metal and at minimum a quarter inch internal diamater, so I had to dig for a while to find one this small and made of plastic. (The man at the local home depot said that no such product would exist anywhere, I showed him :P )
You sir are awesome, Ive been making an animatronic tail, I used a compression spring to be the spine between each vertebrae. it worked really well but didnt work very well once i put a sleeve over it.
thejuggler (author)  mae-kitty2 years ago
Thanks for the compliment, and the spring sounds like a very neat idea. Maybe a thinner sleeve would help?
Beenay252 years ago
I think I just soiled myself! This is amazing! I HAVE to try making these...
How are you attaching the servos to the cables?
thejuggler (author)  Beenay252 years ago
Okay I have now tried this without the pulley wheel thing, ultimately it didn't work. A combination of too little torque and too little motion. On to plan B... (which I will let you know of as soon as I figure it out)
I think you could get the pulley thing to work if you were to use very strong servos (I just found some on ebay that pull a whopping 17kg) and fixing the cables to the furthest point of the pulley.
thejuggler (author)  Beenay252 years ago
I am still working that out, get back to me in a week. :) Basically I need some kind of pulley wheel that will be mounted on the servo.
Krayzi992 years ago
Oh, Slendy...
thejuggler (author)  Krayzi992 years ago
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