Help with a weird project

Please excuse my newbie status in the world of electronics but I really need some help here. I am making a costume that has a bladder of sorts that sits on my back. I would like the bladder material to move up and down to look like I am breathing. I didn’t want to use air and though servos just might do the trick. I want to buy a circuit board, battery and servos from the pololu site but I’m not sure what to get. Any help would be appreciated sooooo much.

The space i am working with is about 4x6 inches (depth 3 inches or so) and the servos need to push up some vinyl fabric at my neck. I’m hoping you can make a suggestions of items that might work. So basically my concerns are that the servos are strong enough to push up the fabric and lower it, the servos and circuit board fit in the space i listed above, and there is a button or remote to turn the servos on ( and info on the best battery pack to use). Any thoughts? I have just over 30 days to complete this so I’m working hard to get everything in order.

I know in the past i have used R/C pushrod for things where i have to move something and things are tight, especially around your neck. The pushrobs will offer a lot less friction overall. do you know how much torque you will need to push your bladder? If you knew that, that would help you decide on the correct servo. with a 4x6x3 box you would have room for a few servos so you might be able to split the load on that bladder.

if you haven’t already seen one, pololu carries a board called a maestro which can control your servos for you and if you only need a few servos a micro maestro might be the way to go.

Remember that your maestro and servos take different voltages , so you might also need a way to regulate the voltage to the maestro with something like a step down regulator. Pololu has lots of those too, its a matter of picking one that will work with your battery and gives you the voltage to run the maestro. with all the docs pololu has, you should have enough information to get it all put together and the maestro is literally click and play because it has a program that you set everything up with on a computer! there is also a great video on how to use that software also.

R/C pushrod tubing/wire should help with moving your bladder with less friction.
how much torque do you need to move your bladder will determine what servos you need.
you want a battery that can provide the correct voltage to your servos (find that in the servos specs).
you want a voltage regulator for your maestro if you are going to use one battery to power everything, or a separate battery pack for it in the correct voltage.

Thank you so much! I will give that a try!!