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BUILD A ROBOTIC ARM FROM A KIT 351

tion the arm components. Such arms may or may not come with a gripper; you can add one
you made yourself or get a gripper kit and build it from premade parts.
This particular arm has 4 degrees of freedom:

• Shoulder rotation, using a rotating base. This allows the arm to pick up objects in a circular
arc of about 90° to each side.
• Shoulder flexion/extension, using a servo mounted near the base.
• Elbow flexion/extension, using a servo mounted off a yoke from the shoulder joint.
• Wrist flexion/extension, using a servo mounted at the end of the forearm.

In almost all cases, arm kits are designed for use with standard- and mini- size R/C servos.
The kits are available with and without servo motors, in case you already have some in your
parts bin. If you supply your own servos, take note of any special requirements that are listed
in the documentation for the arm. Some or all of the servos may need to have a minimum
torque, for example.

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