[Scot Meyers]

Hi all
Im in need of some help, Im working on a new animatronic for christmas, Olaf the snow man.
my issue is this i want the stick arrm to move at the elbow, Im using 1"pvc for the inside frame . I d like to use 3/4 " for the stick arms.
is there a way to move the elbow pvc pipe from inside the pvc pipe ?

 

[CreepyCreations]

You have a few options, but they are all a little complex.
You first have to come up with some sort of hinge that will allow the elbow to bend the way you want it to.
Next, you need some way of controlling the elbow, independantly from the rest of the arm. You could probably use aircraft cable running up the larger part of the arm, and then attached to the elbow portion. if the elbow part isn't too heavy, this should work OK. Then, run the cable down the rest of the arm and over a pulley as close to the joint of the main part of the arm. Something like this:

Keeping the pulley close to the pivot point of the main arm will reduce the amount of movement when the main arm is moved. It should keep them relatively independant of each other.