I am a Fine Art student looking for some help.

Hi,

towards my final year exhibition, I was thinking of creating breathing sculptures covered in fabric.
The 5 or so sculptures will vary in size, from a mouse size to a deer size.
My idea was to use a balloon that would imitate the expanding contracting movement with an arduino uno and a motorised air pump (does that exist?) or if that was too difficult, use servos to somehow imitate that movement.
I was looking for online resources and found rotating servos but I wasn’t quite sure which brands/ what price range/ how it would be made to work or if it would do what I wanted it to.
As I am completely new to Arduino, I really need some help on this project.
Please suggest me what equipment would best suit this project.

photo.JPG

you can also use some motors that move the fabric, by applying multiple motors you can do a "wave" of air.

Is it like this project ?
http://forum.arduino.cc/index.php?topic=214474.msg

robtillaart,

Do you have any recommended servos?
I am thinking of leather as fabric - does that mean it will need a bigger servo?

Caltoa,

I am looking at that right now. The ideas using bellows pump seem ideal, but I am thinking of doing very small ones (mouse size) to very big ones (deer size).

no recommendations, smaller can make small moves larger ones can move bigger pieces.

Just buy 3 of different sizes and check what they can do. (is more fun too!)

Here's a suggestion:

Loop a piece of springy wire (Google "music wire") within the chest cavity and affix the top half of the loop to your fabric so it can't twist. The ~90 degrees of motion that the servo is capable of will cause the diameter of the loop to increase/decrease to simulate breathing. You might need longer arms on the servo for a greater range of motion -- that's something you'll have to tweak. The arrangement would be more compact if the servo were inside the loop (upside down), but I only have two hands and can't demonstrate that and take a picture at the same time.

Just about any basic servo should have the power to do this -- even with a leather skin. Pretty difficult to choose one that won't work, really. You can poke around hobbyking.com for examples and prices of servos, but it would be best to visit a local hobby store for face-to-face guidance.

As far as how difficult it is to control a servo, this is an excellent beginner project and a good starting point should you ever choose to start on a real career in the future XD.

For a mouse-size mechanism I don't have any ideas.

Consider something simpler. Imagine two balloons or bladders connected one of which you compress with a small servo pressing a flat plate. Press and the 2nd bladder inflates more, release and pressure is equalized and it partially deflates

You'll need an air compressor/pressure tank (Though it wouldn't need to be very high pressure) and solenoids to allow pressurization and release, though I'm not sure how effective that would be in appearance, and it might be too noisy. The 2 air bladders and compressing one also would work and might be easier to implement and more realistic. Another option would be using muscle wire: Muscle Wire - 0.012" Diameter (1 foot) - COM-11900 - SparkFun Electronics but that could get expensive

I'd skip the complex approach and just use a servo running code like the sweep example code to expand and contract a very light weight chest cavity assembly.