Monday, March 9, 2009

Remote Controlled Basket Ball Robot

Here I will show you how to build a remote controlled basketball robot. That's right, no joke!

Here's a list of supplies you'll need.

Petsmart:
7" Hamster Ball

Sports Shop:
Basketball

www.servocity.com:
High Torque Metal Gear Servo. I used the HS-645MG
Aluminum Servo Shaft Horn 250HS
(3) Aluminum Hubs 3463H
RZ12-90-128RPM Gear Motor
Servo Mounts
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)
Gyro
(8) Elite 1500 batteries
Cheap ESC (Electronic Speed Control)

Hardware Store:
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
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step 1Sketch / 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.
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step 2Attach 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.
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step 3Make 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.
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step 4Make 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.

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step 5Video of the Servo Saver In Action

Here's a video of how the servo saver works


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step 6The 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.
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step 7Video 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.


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step 8Make 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.
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step 9VIDEO 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.



VidPICTURE.jpg

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