The mask in this project is based on the "Imara mask" designed by Airigami artist Kelly Cheatle (original printable instructions here). It's a two-layer mask with a pouch to hold a disposable filter (made from a piece of non-woven material, such as a single ply of paper towel) and a casing or tunnel where you can insert a wire to make it fit better over the bridge of your nose. It also offers comfy ties that can go behind your head as well as around your ears.
All you need to make it is a rectangle of fabric (8 inches by 16 inches) and two cords made from t-shirt yarn (long narrow strips of t-shirt material pulled until they curl up).
The mask is sized for an adult, but easy to adjust by scrunching up the sides. The width when finished is 7 1/2 inches, and should fit snugly against your cheeks. If you need to make the mask smaller (or larger), just size the rectangle down (or up).
One change from the original pattern: You'll need to add a 1/2-inch gap in the stitching along the bottom to run a wire from the battery pack in your pocket to the Circuit Playground Express board inside the mask.
Here's what to do:
Fold down 3/4 inch from the top of the piece of fabric and press with an iron or your fingers. Fold up 1/2 inch from the bottom the same way.
To make a casing or tunnel that can hold a piece of wire to bend over your nose, stitch 1/4 inch from the top fold with a machine or by hand.
Turn when you reach the end, stitch down 1/4 inch, then go back to the first side -- stopping 2 inches before the end.
Fold the piece of fabric in half, wrong side out, and sew the raw sides together 1/2 inch from the edge.
Turn the mask right side out. You can press the seam flat if you wish.
Take one of the t-shirt yarn cords and insert it into the mask. If you're machine sewing, pin the cord along one side of the mask.
Stitch a casing for the cord, about 5/8 inch from the edge, being careful not to catch the t-shirt yarn in your stitches.
Stitch the bottom of the mask closed -- stopping a little more than an inch from the side to leave an opening for the battery pack wire.
Insert the other cord along the other side of the mask. Stitch the casing to hold it closed the same way as you did the first.
If you want to add a wire to make the mask fit better over your nose, cut a piece of wire about 4 inches long. With pliers, bend the tips over to hide the sharp ends.
Insert the wire into the opening you left in the top seam of the mask and center it. Wear the mask with the wire side facing out.
To finish the ends of the cords, you can simple knot them. To wear the mask, tie the top ends together behind your head and the bottom ends together behind your neck. You can also tie the ends of one side together to make ear loops.
Another way to finish the cords is to use beads with a large hole, like pony beads, as cord locks.
First, decide whether you want to wear the cords behind your head or as ear loops.
Then take the ends you want to connect and pinch the ends together. Use something with a blunt point to help you push both ends through the bead at the same time. Here I used a bamboo skewer with the pointy tip snipped off.
Then cut off any extra if you wish and knot each end as before.