Here I will show you how to build a remote controlled basketball robot. That's right, no joke! I have built a similar ball for the HARLEM GLOBETROTTERS and now you can build your own.
Here's a list of supplies you'll need.
7" Hamster Ball
High Torque Metal Gear Servo. I used the HS-645MG
Aluminum Servo Shaft Horn 250HS
(3) Aluminum Hubs 3463H
RZ12-90-128RPM Gear Motor
Gear Motor Mount
(2) 1/8 ID Bearings
1/ 4 ID Bearing
Any Hobby Shop:
2 channel radio and receiver set (More channels are fine)
(8) Elite 1500 batteries
Cheap ESC (Electronic Speed Control)
3/ 4" Aluminum Flat Stock
3/ 4" Steel Flat Stock
Misc Nuts and Bolts
Double Stick Tape
Lead weights (Or steel)
Great Stuff Expanding Foam
Step 1: Sketch / Plans for the Ball
Here are rough drawn plans for the ball. It has a Gyro for stability control, a servo for steering and a gear drive motor for propulsion. This ball moves only because the weight at the bottom moves. So, the idea is to get as much weight as far below the centerline as possible. Led or steel weights are added to help.
Step 2: Attach Drive Hub to Ball
Attach the aluminum hub from servocity to the ball using screws as shown. Take care to make sure it's on the centerline.
Step 3: Make the Chassis
Next make the chassis. You can make it out of one piec of Aluminum if you prefer or bolt together 3/4" flat stock. The important thing to remember is to keep all servo splines, bearings, motor shaft in the same plane. Other than that everything can fudge a little.
Take a look at all the pics and you'll get a good idea of what you need to do.
Attach another one of the aluminum hubs to the gear motor drive shaft. Screw some bolts into it and sand them down so they fit nicely in the hub that you just mounted to the ball.
Step 4: Make the Steering Arm
Now for the steering arm. It's basically a piece of 3/4" flat steel bent in a U shape. The battery pack is attached to the bottom of the U and I put lead weights on the sides for more drive torque. You'll see the self designed servo saver on ones side. It's made with the horn shaft, hub and 1/4" bearing mentioned in the materials list.
Step 5: Video of the Servo Saver in Action
Here's a video of how the servo saver works
Step 6: The Cap Side of the Ball
There it is inside the ball. On this end I made a steel bar that attaches to the ball with bolts. It has a perpendicular shaft bolted to in down the centerline that slides into the drive rotational bearing.
Step 7: Video of Gyro Stability
You DEFINATELY want to put a Gyro in. Even WITH the gyro this thing is sqirley. Without it it's almost impossible to control.
Step 8: Make a Basketball Shell
I cut a REAL basketball in half, filled it with Great Stuff Expanding Foam available at ACE hardware. Then I hollowed it out with a dremmel so the hamster ball will fit inside snug. Pop the shell on and drive away.
Step 9: VIDEO of the Ball in Motion
Here's a Video of the Basketball In Motion
And here's one of the hamster ball without the basketball so you can see the insides.