In fact, I wanted to build a robotic tripod for my camera. I found out, that it's more difficult then it looks. After some experimenting I build this simple robotic arm.
I you want to build it too, you need:
- Lego Mindstorms NXT kit
- a computer
There are only two rules you have to follow while building ANY robot:
1. rule: KISS (Keep it simple, stupid!);
2. rule: "The triple-F" rule a.k.a. FFF (Form following function!)
Step 1: Constructing the Base
The base (in our case) are just a few beams that support the robot. More advanced robotic arms have motors in the base. These motors than move the arm, without moving themselves. Usually, the base has a motor that rotates the arm, but my arm rotates itself.
You can be much more creative with the construction of the robot then I was.
Step 2: Building the "rotation Module"
It's very simple. It rotates the arm left and right and supports the other two modules. It's based on Matthias Paul Scholz's 90 degree join at:
Step 3: Building the "tilt Module"
On top of this module there is a small platform, to which the claw is attached, but more about the claw later!
Attaching the two modules together couldn't be simpler. They are held together by a single shaft/axle, around which the "tilt module" spins. The arm can tilt for nearly 90 degrees, that's a lot!
Step 4: The Claw Module
I'm really sorry, but I'm afraid that I can't tell you much more about it. Pictures tell everything...
Step 5: Attaching the Sensors and Wiring
The light sensor (Port 3) is located on the claw and lets the robot know, if the ball is there or not (and can recognize the "color" of the ball). The other two sensors are located on the platform of the "tilt module". Touch sensor (Port 1) serves as a sort of a button for me to press while the sound sensor (Port 2) measures the noise level (so I can give the robot commands with a clap for example).
At first, I wanted to include the US sensor as well, but I realized that it's relatively useless. You can still see it on one of the photos, but I removed it afterwards.
Now all that is left to do is the wiring. You must make sure that the wires do not disturb the movement and function in any way. You must also consider wire lengths for each sensor or motor.
Wiring (my robot):
- touch sensor -> Port 1
- sound sensor -> Port 2
- light sensor -> Port 3
- "rotation" motor -> Port A
- "tilt" motor -> Port B
- the claw -> Port C
Step 6: Attaching the NXT Brick
Step 7: Decoration and Finishing Touches
You can be much more creative...
Step 8: Programming
You are very free with your programming, that's why I won't talk about the programming any more.