Picture of DIY artificial muscle

Question: is it possible to build artificial muscle using household items?

Hypothesis: if polyethylene fishing line is coiled tightly, then it will be able to condence when heated because the tight coils will try and unwind when heated

Hi my name is anders and I have always loved the idea of exoskeletons, robots, and petty much anything that moves mechanically. Exoskeletons especially, they always seemed to be the coolest. The idea of being able to run faster, jump higher, or even lift a car above your head is awesome. One of my dreams is to be able to build one of these exoskeletons to do all those those things (besides lifting a car above my head, probably not going happen), so I've been doing quite a bit of research. I've looked into hydrolics and motors, but both are big and bulky and a bit out of my price range. I kept looking, and looking until finally I found something that would work, carbon nano tubes are ultra light and very small and compact, they are also extremely strong. Why does this matter? the university of Texas, dallas recently discovered that carbon nano tubes contract when an electrical current is passed through them, quite ingenious if I do say so myself. There is one problem with carbon nano tubes though, they are very difficult to make and aren't being sold, at least not to my knowledge. There I was back exactly where I started, square one, no other way to go, so some time went by and I went on YouTube and typed In "artificial muscle" and in the auto complete section below the box it said "artificial muscle fishing line", curious I clicked on it and found a pretty interesting video that I decided to watch it was an animation of a line being spun until it sarted forming coils, then it showed it stretching and then contracting. I watched some more videos and found out that these are extremely cheap and easy to make, assuming you've used a drill before. I also found out that their contraction strength was stronger than carbon Nanotubes and they were a hundred times stronger than a human muscle of equivalent size which is awesome. Another thing I learned was that they were made by the same university that makes artificial carbon muscles, this was very exciting for me because a would now be able to build these, and build a cheap exoskeleton at my house (if I can find the time).

Why did I build this and put it on instructables? The reason I built this was because there wasn't very many sources to get the info on how to build this. I also made it because I wanted to build a cheap, but effective replacement for motors and hydraulics.

Thank you for all your support, and tips to help me improve my instructables. Without you guys I wouldn't be doing this right now, you should expect many more indestructible in the future so don't forget to subscribe to me and/or favorite this instructable. If you have any question or concern then be sure to comment, or if you just want tell me how awesome this is that's fine too. Here it is, hope you enjoy it. Don't forget to vote for me, thank you.

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JeffreyW5 days ago

How about interweaving nichrome filament to add a heat source?

Pure Carbon (author)  JeffreyW3 days ago

Nichrome would defiantly work, this upcoming week I was planning to start steel wire tests, then I think I will move on to testing Nichrome wire and report which one works better here on this page. I will also make a video about my findings on my YouTube channel.

-Thanks for the comment

twiz.graal7 days ago
I have actually been developing a new concept of prosthetic hand using this technology. Although I do realize that this is not at the peak of artificial muscle fiber technology, I plan on doing extensive scientific research regarding the fishing line technique. I'm positive that this concept will give rise to new developments, of which I will use to update my relatively new design.
Pure Carbon (author)  twiz.graal5 days ago

I've done quite a bit of research on these. I've created an equation to calculate how much current is needed to heat a steel wire of a certain length to get about 150f (which is the ideal temperature for contracting these). The only reason I'm doing this research is because I'm building an exoskeleton which I hope do do an instructable on in the future, where I will release the code for the arduino that I have controlling The muscles. This will hopefuly all be released this summer.

-Thanks for your comment twiz.graal

All I need to do now is get my hands on one of those damn 3D printers x_x
Pure Carbon (author)  twiz.graal5 days ago

I know right! I've been entering contest after contest trying to win one, but so far no luck.

kik1 month ago

I have made some of these back when it was annaunced in the media, I had very nice results operating the muscles with boiling hot water. Contractions are large and strong.

Pure Carbon (author)  kik1 month ago

I use steel wire and a battery to contract these. I'm currently working on an exoskeleton using these which I hope will better explain how these work and show some real world applications for these for YouTube video.

kik Pure Carbon20 days ago

Please share a link to video when you are ready. And can you share details on wire and current/voltage you using to actuate them? Keep up the good work.

Pure Carbon (author)  kik20 days ago
Absolutely, it will be coming out within the next month or so. I've been extremely busy so I haven't been able to make the video. If you subscribe to me on YouTube I can guarantee that you will be one of the first people to watch it. I've made an equation that will allow people to calculate how much power is required to produce a certain amount of heat if they know the length and the Gage of the wire. I thank you for your patience with me.
RandomIdeaMan10 months ago

nice explanation.

I heard about this on a podcast a month or two back, but haven't had a chance to play with it my self yet.

If you use copper wire (as you said at the end) rather than yarn would you be able to heat the wire to make it contract? Or would the stiffness in the wire be too much for the fishing line to over come?

Pure Carbon (author)  RandomIdeaMan10 months ago

thank you for your comment, I haven't tried it yet but I'm assuming that the fishing line was condensed when you put It on, the weave would allow it to stretch and still pull the weight. Just be sure that the copper wire at a low gauge and is coated, conducive thread might work as well.

I am sure your muscule does'nt work.

Pure Carbon (author)  iskanderus1 month ago

On the video from Texas the process of contractions was very slowly. There are lots of additional conditions to each strand can be contract. And about step 10. It seems to me "step10" kills the ability to contracting.

Pure Carbon (author)  iskanderus1 month ago
Have you done any research on these at all? The reason they contract is because of the tight coils that are constantly trying to unwind. Because they are wound in the opposite direction that the muscle is trying to unwind, the two forces are equal to each other so they stay nutrally balanced. This is what keeps them in the nice coils. When heat is applied to them the coils try harder to unwind, but because of that opposing force they can only; you guessed it contract.

You also said "There are lots of additional conditions to each strand can be contract." What conditions?

I also read a theory. I've been watching these studies a year. And yes, I'm trying to repeat the result. Nothing interesting comes out. And by the way, "the performance of each coil can be varied based on the weight applied to the end of the cord during twist insertion, and, of course, by the total number of twists" (conditions).

Grall5 months ago

I like it. But I how fast can the contractions be? Does it speed up with a more abrupt application of heat? Conversely can it be slowed down?

Pure Carbon (author)  Grall5 months ago

It depends on the temperature. I wrapped some steel wire around it, hooked a battery to it, and it contracted very quickly. If I had to guess with more wire there would be less heat making it contract slower

stormneel9 months ago

How much can it lift?

Can this also be used run faster and jump higher?

Pure Carbon (author)  stormneel9 months ago

thank you for you question. It can lift a hundred times more weight then a human muscle of equal size, so if you were to make an exoskeleton using these then you would be able to run faster and jump higher, some advantages this has over things like motors or hydrolics is that it's lighter, cheaper, stronger, and contracts and expands better. If your trying to build an exoskeleton then I strongly recommend using this.

nerfrocketeer10 months ago
Haha cool!
Pure Carbon (author)  nerfrocketeer10 months ago

thank you.

rimar200010 months ago

Good work!

Pure Carbon (author)  rimar200010 months ago

Muchos gracias.

apburner10 months ago

Interesting. A video would have been useful. Perhaps a weight hanging on you muscle going up and down as you apply and remove the heat.

Pure Carbon (author)  apburner10 months ago

I know, I know, but I don't have a decent video camera. Here's a video of the one that the university of Texas made though, thanks for your comment ;)