// www.chrisgavin.com: Adventures in DIY: Motion Control Rig

Sunday, April 10, 2011

Adventures in DIY: Motion Control Rig

For the next stop motion short film I'm currently making for Canongate Books, I found that I needed to shoot accurate rotations of many small three dimensional objects. This seemed like a good application for the geared stepper motor and Stepper Bee controller board that I've had lying around since my long-abandoned DIY film scanning project.

I dug the bits out, rigged up a small stand to hold a bearing and (after a bit of fiddling about with O-rings) the stepper motor drives an 8mm threaded shaft that I can attach my objects to. The stepper motor already enables pretty fine control (it's rate at 1.8 degrees per step) but with the gearing still attached, it actually takes around 700 steps to perform a full rotation.

The AutoStep software that comes with the Stepper Bee card is pretty basic but allows me to set the number of steps and duration of each step.

It all works a treat, I can shoot the rotating objects in single steps (for stop motion shooting) or allow the motor to run continuously at a controlled speed (for live action shooting).

Technically this IS motion control, albeit a simplified single motor rotation-only motion control.
Here's the rig...

DIY Motion Control Rig: Stepper motor drives gears then an o-ring drives 8mm threaded shaft. Note the Stepper Bee card with DC power cable and USB cable to host PC.

No comments: