In the realm of wearable tech and cosplay, being able to create shape morphing garments and accessories is a great skill to have in your bag of tricks. One way to accomplish movement and shape changing elements is to embed small inflatable pouches that move and morph when filled with air by a small pump.
This Instructable will cover a technique I've found effective in designing and constructing pouches as well as show a couple of potential applications for using the pouches.
Step 1: Gather Materials
The image here shows all the components for a specific project I was doing, but all you need to make some pouches that you can inflate is:
Step 2: Cut Fabric
You can make these any shape you can dream up, but for ease of explanation, here is how to make a simple rectangle with rounded edges on one end.
1.) Cut a long strip of heat sealable fabric, fold it in half and make a crease. This will be the outer layer of the pouch.
2.) Cut two smaller pieces of regular fabric that are at least 1/2" small around all the edges than the outer strip. These will create the inner pocket
If you are coating your own fabric, cut a strip of the coating material slightly smaller than your fabric strip, iron it on, and remove the paper backing. You want to coating material to be smaller than the fabric, otherwise you will end up with a mess on your iron or ironing board.
Step 3: Install Barbed Hose Connector
You want to install the hose connector in the crease of the strip.
To ensure a secure, air tight fit:
1.) Cut a piece of the silicone tubing that is the same size as the neck behind the barb on the hose connector to act as a gasket.
2.) Poke or snip a small hole in the middle of the crease in your sealable fabric strip and poke the barbed hose connector through.
3.) Slide the piece of tubing over the barb to secure it in place.
Step 4: Seal and Trim Pouch
1.) Lay the heat sealable fabric strip with the coated side up.
2.) Place one of the regular fabric pieces on top with the edge aligned to the crease and under the hose connector.
3.) Place the second fabric piece on top of the first and on top of the hosed connector as you are folding the heat sealable strip in half.
Basically, you need to sandwich the hose connector in between the non binding layers of fabric to create the air pouch.
4.) On high heat, iron and make sure the edges are well sealed.
5.) Trim the pouches to match the shape of the inner fabric making sure to leave enough space for the sealed seam to hold.
Step 5: Connect Pouches to Pump and Valve
If you just have one pouch, you can connect it directly to the valve and pump with the silicone tubing. Depending on what effect you are going for, you may not even need a solenoid valve. Its purpose is just to close and seal the air in the pouches after it is pumped in and then release the air when it is opened.
if you have multiple pouches, you will need a tube splitter. The ones I got were too big, so I melted them with a heat gun and shoved hose connectors into each port. Not pretty, but it works.
You can see the layout of the system I designed. I have six pouches, so I connected the two tube splitters at the top, connected the pump to the bottom right and the solenoid valve to the top left.
On the bottom of the pump, one of the terminals should be marked red. This one connects to power, or to a digital pin on an Arduino, and the other terminal connects to ground. The solenoid valve can be hooked up either way. Just connect one wire to ground and the other to power, or a digital pin on an Arduino.
Controlling this with an Arduino is simple. Just digitalWrite the pump pin HIGH to turn it on and blow air, and LOW to turn off. Same for the solenoid: digitalWrite the valve pin HIGH to close and seal the system and LOW to open and let the air out.
Step 6: Examples
The purpose for the pouches I made was to make a scarf that will inflate and keep your neck warm. By inserting the pouches in to a scarf and folding them over, it creates a fairly dramatic shape change when they inflate and unfold themselves.
Here is another idea and an example that you really can make these in any shape!
Here is a great paper by the MIT Media Lab that discusses this topic in greater detail
And the website of one of the primary contributors: http://oujifei.com/aeromorph/