Hydraulic JudoBots by WYE_Lance
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titlebot.jpg
This is the Holy Grail among the students in my extracurricular engineering class. The project involves constructing a robot that uses a simple hydraulic system to power a lifting arm and a pivot. Two robots face off and try to throw each other off of a table! It'll make more sense after you watch the video...
 


More footage from actual student-built JudoBots:
I call them JudoBots because of the way they seem to throw and grapple with each other during combat.

Although designed for children in grades 4-6, I think just about anyone can have fun with this. Even parent's can't resist trying it out :)

The bots are assembled from four components built separate from one another: the base, the stand, the arm, and the hydraulic system. The hydraulic system uses plastic syringes as pistons and water as the hydraulic fluid.

The cost per bot is about $4.00 and it will take up to 2 hours to complete, but you'll definitely need to schedule more time for some epic battles!

This project has been submitted for both the Teacher Contest and the Toy Challenge 2. I believe that JudoBots are a great project for both education and play in equal measure. 

Difficulty: 5/5
Prep work: 5/5
Setup: 4/5
Cleanup: 4/5

Learning Objective
By operating a JudoBot, students will experientially comprehend the basic principles of hydraulics. Building and testing Judobots offers students the opportunity to evaluate materials based upon density, rigidity, and mass. Using the JudoBots in battle gives students hands-on knowledge of how to utilize hydraulics to effectively apply leverage to manipulate a mass. When the project is finished, students will walk away with a new appreciation of applied engineering (and an awesome new toy!)

Update Feb. 2012: After recently conducting this project with about 30 kids, I redesigned many aspects of the JudoBot. Attaching the hydraulics, which once was the most difficult step for some students, is now much easier. All of the photos and instructions are new - enjoy!
 
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Step 1: Materials, tools, and design criteria

 

JudoBot Criteria
  1. The base of each JudoBot must fit within a 10-inch square. This is to prevent students from building sprawling robots that cannot be flipped.
  2. Material limitation: craft sticks (50), craft cubes (10), cubes with holes (10), syringes (4), adhesive bumpers (10), decorative woodcraft/extra woodcraft (5), everything else within reason.
Material limitations are in place to promote resourcefulness and to reduce cost. Also, clever students can no longer pile hundreds of sticks onto their bot in order to make it too heavy to move.

You may choose to use other materials. This is what I use because I need to streamline my materials to fit with the other projects in my program, as well as keep the cost per project low.

*The cubes pictured are actually from Bazic, but they have recently discontinued this product. Although the cubes depicted have holes drilled on all sides, this is not necessary. I chose to use Bazic's cubes in this 'Ible because they are colorful, which helps illustrate the design. The product I linked is my current substitute, but please let me know if you find something better
sparklesareinme567 says: Apr 9, 2013. 9:37 AM
yo you know the whole pressure thing yay that is what works the thing what ever it is you know wat evs
sparklesareinme567 says: Apr 9, 2013. 9:30 AM
Judobot Tournament! cant wait fir the thrill of the amazing tounament
sparklesareinme567 says: Apr 8, 2013. 9:45 AM
what types of judobots can be made? like creative ones?
Digital Teacher says: Mar 8, 2013. 4:09 PM
Idea: create a team event after the battles......a pass the parcel sort of thing.....vid the results. For a team vid
krouterer says: Sep 18, 2012. 11:53 AM
This is a awesome machine !
I build mine this afternoon in 45 minutes, and it works great. I showed my students (5/6 class) your video this morning and they where fascinated. This will be our next Project to do. I can't wait to see what the kids will construct!
Thanks for this good idea!
WYE_Lance (author) says: Sep 19, 2012. 6:29 PM
Very cool - let me know how it turns out, and maybe post some photos
chriscook8 says: Sep 19, 2012. 4:56 PM
Hey thanks for the awesome project, we just used it for our kids program at our hackerspace. http://acemonstertoys.org/node/119 We had about 25 kids building them and it turned out fantastic!
WYE_Lance (author) says: Sep 19, 2012. 6:28 PM
Wow, that's great! Thanks for sharing that with me :)))
Bindi 3000 says: Apr 11, 2012. 12:58 AM
and it is awsome
micraman says: Apr 9, 2012. 6:33 AM
Hi there! I just wanted to say thanks for the wonderful idea! I adapted the syringe concept and made a catapult which won first prize! Thanks!
IMG_0979.JPG
WYE_Lance (author) says: Apr 9, 2012. 3:44 PM
Wow, that's awesome! What contest did you win first prize in?
micraman says: Apr 10, 2012. 3:21 AM
Well it wasn't really a contest we were supposed to build a mechanical toy in Physics.
anibioman says: Mar 26, 2012. 10:05 AM
these are really really cool i made something similar in technology class but we made claws and used them to pick up ping pong balls in this little game of who can pick up 5 balls faster.
carladee says: Mar 11, 2012. 1:11 PM
Great project! I recently used this in my high school physics class. The students really enjoyed it. A couple of groups added a third syringe to make the arm lengthen. I even had one student make his robot walk.
WYE_Lance (author) says: Mar 11, 2012. 2:34 PM
Amazing! Thanks for sharing that with me. Do you have any photos or video of your student's designs?
NightHawkInLight says: Feb 26, 2012. 5:44 PM
Very very cool. It's genius to use syringes as both the cylinders and pump. Simple and functional. Reminds me of building backhoes and dozers with my pneumatic Lego cylinders. If I don't place in the Play contest I hope you're the one that beats me.
WYE_Lance (author) says: Feb 28, 2012. 7:07 AM
Thanks, but I got the syringe idea from hydraulic robot arms that I found on Youtube and this site.
biochemtronics says: Feb 27, 2012. 7:43 AM
This is so cool and a great fun way to teach kids so much. I am highly impressed.
iPD says: Feb 10, 2012. 3:20 AM
Wonderful! :-)
jetringer says: Feb 2, 2012. 11:51 AM
Just built my first one and it's pretty cool. My students are getting excited to try them out.
WYE_Lance (author) says: Feb 2, 2012. 7:11 PM
That is awesome!! I'd be thrilled if you could post some photos or video of the project in action.

I am planning an update for this project, but I'd like you to here it first:

Use masking tape to secure the piston that actuates the pivot, not cable ties. Students requesting for help tends to bottleneck at this step, so using tape is much easier to attach and readjust (and it's just as effective).

I just finished conducting this project with about 30 4th-5th grade students. Take your time with each step, especially the testing/redesigning phase. Many robots perform less than impressively at first and require some additions and adjustments. Be sure to bring unassembled components for the students to refer to. Have fun!
I_am_Canadian says: Jan 29, 2012. 8:57 PM
Fantastic!
gmtanner says: Jan 29, 2012. 12:56 PM
Great Idea!!!

How long does the typical build take?
WYE_Lance (author) says: Jan 29, 2012. 6:26 PM
Each one takes about 1.5 hours from start to finish
technologyguy says: Jan 27, 2012. 1:52 PM
A fantastic way to cover the curriculum, involve the students in "doing" and also allow them to have a lot of fun. They soon learn if their design is viable. Proof of concept is the competition. It either wins or loses. Some real- world learning! Wish I'd thought of it!
stumitch says: Jan 24, 2012. 1:15 PM
VERY well done! my students all want to build it!
-stu
ZeroSight says: Jan 20, 2012. 8:45 PM
this has earned you a subscriber. the idea of challenging young kids to think an build is also great.
macrumpton says: Jan 20, 2012. 4:51 AM
Very cool. It would be interesting to create a computer interface for these. Maybe a 2 motor setup where one motor selects which plunger to operate and the other actuates the chosen plunger.

PS I thought Sumo was the sport where the winner gets his opponent to step outside of the ring. Is Judo like that too?
WYE_Lance (author) says: Jan 20, 2012. 8:58 AM
Yes, it is more like sumo in some ways, but sumobots are already established as small bots with wheels that try to push each other out of a ring, like this: http://www.youtube.com/watch?v=YpqmBEG349I&feature=related
fozzy13 says: Jan 19, 2012. 4:19 PM
This is really cool! Being a judo player, the title of this instantly interested me. I've seen similar things on Youtube before, good job.
Aron313 says: Jan 19, 2012. 3:29 PM
That would be awesome to play!!!!!!
Kiteman says: Jan 19, 2012. 2:29 PM
Gosh, that's brilliant!
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