Introduction: CARDBOARD Robotic Hydraulic Arm

Picture of CARDBOARD Robotic Hydraulic Arm

Hello Instructables!

In this Instructables we will be showing you how to make your very own Hydraulic Arm! This project focuses on the principles of hydraulic movements. To do that we made a small scale demonstration of a Robotic Hydraulic Arm. We managed to do some pretty cool tasks with our ''Arm'', do check out the video down below for a better understanding!

This project is entirely made with cardboard and a couple of syringes, all the plans and blueprints are available. What are you waiting for? Let's get making!



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Step 2: The Materials Needed:

Picture of The Materials Needed:

One of the reasons that this project is fun to make, is because the materials needed are very cheap and can be easily found at home!


  • CARDBOARD ( preferably a double corrugated board although you could manage with a single corrugation. Will result to a slightly weaker model.)
  • 10 ml SYRINGES x 8 (these syringes will act like the muscles of the hydraulic arm)
  • 2m long TUBE (the tube needs to fit snugly into the opening of the syringe.)
  • SUPERGLUE (you will need a lot!)


  • X- acto knife
  • A pair of scissors

Let's get making...

Step 3: Making the Blueprint

Picture of Making the Blueprint

The whole design fits on to two A4 size sheets. We first sketched the parts and then keeping in mind the mechanisms made the blueprint.

I have made this step much easier for you guys, all you need to do is to print out the templates in the next step. If you wish you can tweak the design as per your looks : )



We designed all the parts so that you don't have to measure and draw. Simply print out the two files, with the same scale, all parts are in their right dimensions. Stick the printouts onto the cardboard and get making!

The toothpick holes are there too, if you have any other doubts we have uploaded lots of pictures so that you have a better visual understanding! Happy Making!



Follow the templates and carefully cut out both the Arm Support and Forearm. Note that I had started it out with a single corrugated cardboard but then I had to strengthen it by adding a second layer.

Start by making a rough cut and then repeatedly cut deeper and deeper until the piece pops right out, don't force!


Picture of THE GRIPPER

Once you have cut out the gripper you can proceed to making the holes.



All the points on the templates are where the holes should be. These holes are the size of your toothpicks so find the appropriate bit. Start by poking the tip of your knife to form a small dent, a guide for the bit. Then carefully drill out all the holes and you are ready to start assembling the ARM.

TIP : You will notice that just by the weight of the drill the hole gets poked. though the small spacers tend to fold and get ruined. To avoid that from happening you can push through a screwdriver instead.

Step 8: Dry Fit

Picture of Dry Fit

I would advise you to start by assembling a dry fit to make sure you know which piece goes where. This will avoid any mistakes or confusions later on. The plans are well explained and I don't think you will have any problems in following them : )

This pictures will give you a visual idea however

Step 9: Masking Tape to the Rescue

Picture of Masking Tape to the Rescue

You will notice that the ends of the pieces with extensive use weakens and starts separating. We found an easy way to fix that by covering all the edges of the pieces with strips of masking tape! This not only strengthens the whole structure significantly but also adds a nice look to our model!

Step 10: Preparing the Syringes

Picture of Preparing the Syringes

Take four syringes, these will be the ones attached to the Arm. To attach it in a way that the joint can still pivot you need to adjust the syringes like so.

  1. Clip the extra plastic piece on top as it can cause unnecessary width
  2. Drill a hole around half a cm from the top of dia the size of the toothpick. One out of the four syringes will have two holes at the top, this being the gripper's syringe.
  3. Get two zip ties and close them in this ''figure of eight'' shape. Tighten one loop around the syringe then slip in a toothpick on the other one and tighten it till it bits tightly, finally clip the extra bit of the zip tie.

The pictures will remove any doubts!

Step 11: Rotating Platform

Picture of Rotating Platform

To make the rotating platform, find an old pen cap, you will use that as the axis on which the arm rotates on. Cut a piece of cardboard with length and width little bigger than the Support pieces.

Make a hole in the center with dia a bit bigger than the pen cap's, to permit easy movement. Stick the piece with superglue to the support pieces. Then grab a much bigger rectangular cardboard piece to form your base. Like before drill a hole in the center this time so that the cap fits snugly. Push the cap in and put dabs of glue for strength. Then slip in the main body...

Step 12: Rotating Platform Mechanism

Picture of Rotating Platform Mechanism

Now that we have the mechanism ready it's time to add the syringe. Cut the pieces and stick them together like in the pictures. Then attach one end of the syringe to the newly made piece. Stick the piece with superglue onto the main body, all that's left is to compress the syringe and simply insert a toothpick into the base. this will automatically fix your syringe and convert the movement into a rotation of the arm.

Step 13: The Gripper!

Picture of The Gripper!

Insert the semi stiff copper wires in the inner holes and bend them outwards so that they cant come out. Then twist each one into their respective holes in the syringe. I bent two small pieces of cardboard around a ruler to give me my end of the gripper. To add grip we cut out two tiny rectangles from an old ''Yoga Mat'' and stuck them at both ends. Fix the syringe and stick the triangular part of the gripper to the arm.

Step 14: Snip the Ends

Picture of Snip the Ends

You are almost done, just clip the ends of the protruding toothpicks.


Picture of TESTING TIME!

Mix 4 colours with water each in a glass, and fill the 4 ''controllers'' (remaining syringes). Then cut your tubing into four equal parts. Attach the end to the controller and squeeze the syringe till water starts coming out at the other end. This is to make sure you don't loose any pressure. now attach the other syringe ( the one in the arm) making sure it's fully compressed.

Press and pull to see the magic!

Step 16: It's Complete!

Picture of It's Complete!

And it's done! Now go ahead and test your new Hydraulic Arm. Go pick up a can and try to place on a given target. Show it off with your friends!

The simple Hydraulic System is what makes this project really stand out and the fact that it's so easy to build. Hope you enjoyed this instructables, see you next time!


Yayataylor (author)2017-11-17

hi. I’m currently working on this but the tubing is slighty too wide for the syringe, resulting in leaking. Is there any way you recommend that I fix this? I don’t want to have to buy new tubes. But if i do have to, what type/brand/material/Store do you recommend?

Technovation (author)Yayataylor2017-11-18

A quick fix could be to wrap some tap around the mouth of the syringe then stuff the tube.
Any local pharmacy should be having the right sized tube for your syringe. Hope that's helpful!

bdele (author)2017-11-08

Is there any way someone could take those blueprints and put dimensions on them? I would like to design this on SolidWorks and use our laser cutter to make it out of wood.

Technovation (author)bdele2017-11-09

Thanks will give them to you as soon as possible

bdele (author)Technovation2017-11-13

How much longer do you think it will take?

bdele (author)Technovation2017-11-09

Thank you! That would be great.

Technovation (author)bdele2017-11-09

In that way send me your contact and I could send you the needed dimensions of the model

bdele (author)Technovation2017-11-09

Technovation (author)bdele2017-11-08

I could do that out it's going to be a bit tedious, could I give you one length and you can deduct the rest?

bdele (author)Technovation2017-11-08

I don’t think I could do it with one length. But, thank you.

Jackie & JasonS (author)2017-09-14

This is a great project. I am building it now with my fifth grade students. However, do you have the .dwf file for the parts? I would like to use a laser cutter to make the parts with some plastic or possibly 3d print them.

I converted the plans into STL files for 3d printing. Here's a link

tracey_harber (author)2017-09-29

I found syringes and tubing at a local ACE hardware store. You should also be able to find them at Farm & Home stores and tractor supply places.

rocart (author)2017-09-25

Does anyone have a source for plastic syringes for pushing liquids

and for the tubing that will fit the inside diameter? I am a STEM teacher and

would need to order 150-200 syringes plus the tubing.



KathyFairclough (author)rocart2017-09-26

I purchased mine off eBay, 10 ml syringes, the pharmacy do sell them but they were cheaper from eBay. I also ordered 4mm pond tubing from eBay. We are looking forward to making them.

rocart (author)KathyFairclough2017-09-26

Thank you, I found some info in another Instructable and was able to order syringes and tubing with the correct ID from Amazon. Looking forward to a hydraulics project with my MS STEM classes.

Technovation (author)rocart2017-09-25

Local pharmacy? That's where I got mine from...

jacksonperrin (author)2017-08-09

Superb tutorial, just finished making one, now plan to incorporate it into my high school robotics class curriculum.

Wow that's great, thanks!

taahirmaula (author)2017-08-06

Firstly, I want to say a huge THANK YOU for the project steps. It was an awesome bonding session between my 6 yr old and I.

Secondly, we went a bit bold and decided to try out the dremel and replaced the cardboard with perspex. The results are more stable however, one needs more patience with the cutting and glueing process.

My son is so excited to play around with this until he gets board of it ;-)

Technovation (author)taahirmaula2017-08-06

Glad to have inspired someone! Do send me pics, curious to see how it turned out : )

udubinsky made it! (author)2017-07-17

This one is greate and opened my mind for ideas...

Technovation (author)udubinsky2017-07-17

That's awesome I'm glad yours was successful keep up the great work!

charles10 (author)2017-05-26

It's great that the author made a template for everyone to follow and provided a video of how it works. But the video itself is misleading especially in the Coke can toss, that was just some gag. Someone in our class used your instructions and gave this feedback: the design on the video, template, and in the photos sometimes don't match [see "dry fit" of the arm vs the actual finished product]. The instructions are a bit vague, like you can tell he was in a hurry to write it for Instructables; for example "The Gripper!" part showed the finished product, then the parts, then the gripper in action, no in between set up photos. Sure, it pretty much is common sense to make it: just look at the photo and piece it together. I'm talking about the instructions themselves they are vague. Check the template pieces, they seem to be not proportional. They printed it out and the support is too short for the forearm and arm, especially if you use corrugated board like the auther. The Big Spacers say you need 6 but it turns out you need more. They had no idea where the Small Spacers should go.

Technovation (author)charles102017-05-26

To start with I really like people like you, thanks for giving that critique you are absolutely true!
I'm sure you must have seen this video circulating on the net, well I saw that one too and I realised, "wow that's so great!" But then when you look closer, neither the dimensions or how it's assembled are clear. This really got me thinking that such a cool project needs to be shared,and that's what I did.
As we had no clue of the dimensions we paused the video and through proportion figured it out but I can assure you the ratios are still wrong as it can't to such wide ranges of movement. But hey it finally worked out : )
Now the templates was kind of an afterthought, we were like instead of describing the piece and it's dimensions why not make a template , this to be honest was done an hour before we published it, although we still think they are correct, will check and let you know.
Finally the gripper part, if you would actually make one you would find out that this part is a bit tricky, I actually messed up few times and had taken pictures of those attempts, but when I made the final version I forgot to actually take the pics, that's why the lack of pictures , my bad.
That said come let's make it a bit challenging too : D I hope they had fun making it, thanks again for your comment

Grasshopper1221 (author)2017-05-08

Made this a month ago after seeing it on Facebook. Mine is wood :D

That's so neat and impressive did you document it or a take a video? Would love to see it work

No I did not sadly... But it is the same pretty much. well done BTW!


ThirdEarthDesign (author)2017-05-10

That's pretty awesome and a great educational tool to demonstrate the principle of hydraulics. Keep up the good work! Voted for you :-)

Hey thank you so much!

Filio Schiavina (author)2017-05-08

Very neat work.


Craftcorner (author)2017-05-06

An extremely well done project with neat and clear steps and a wonderful outcome!
I really like how you have incorporated the idea of hydraulics into such a simple and easy project!
I definitely think this should be considered while choosing winners! You totally deserve my vote!

Technovation (author)Craftcorner2017-05-07

Thank you for that positive feedback! Well I too feel they should consider us while choosing the winners!

38ren (author)2017-05-04

This is a crazy awesome project!!

my vote ~~~> you

Technovation (author)38ren2017-05-04


About This Instructable




Bio: We are two young inventors, Kousheek Chakraborty and Satya Schiavina, with the dream of becoming the craziest scientists. We like making robots and bringing inanimate ... More »
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