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.
Prep work: 5/5
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!
Step 1: Materials, tools, and design criteria
- Craft sticks
- Craft cubes
- Cubes with 5/32" holes*
- Robust wooden skewers 1/8" diameter
- Decorative woodcraft (optional)
- 10ml plastic syringes (or bulk)
- Vinyl tubing
- Adhesive bumpers
- 4" cable ties
- Hot glue guns
- Glue sticks
- Multicutter (recommended)
- Food dye (optional)
- 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.
- 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.
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