Summary

A different approach for a pan/tilt movement.

The "Z-mover" additionally can move the thing inside
back and forth, which might be
useful for a pen.

Can also be used to move paddles for a rowing boat model ;-)

Instructions

Software from the YouTube video is availabe from here:
http://www.askrprojects.net/additional/xyzarm.zip

It additionally requires:

Notice that the fixture is only provided as an example and
was constructed to hold an 11mm tube.
You'll need to create your own, custom fixtures...

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WHAT TO DO:

Print the XYArm part.
Mount the 2 servos with small metal screws.
Create your own fixture:
ÃÂ ÃÂ 0ÃÂ° (servo, top)
ÃÂ ÃÂ 90ÃÂ° (servo, right)
ÃÂ ÃÂ 225ÃÂ° (rubber band, lower left)
Attach the fixture to the servos with sewing cotton.
ÃÂ ÃÂ Fix sewing cotton with super glue (knot or loop).

BOM: