It is a universal law that a long cord, when placed into a bag or pouch, will snarl and tangle. Retractable earphones are a common solution to this problem, but what to do if you already have a good set? You can make earphones retractable by placing them inside a wire retractor, which you can make with a shoebox, a rubber band and an empty tuna can. The retractor consists of a cord reel and case.
Making the Cord Reel
Measure the can. Cut out a cardboard circle and two cardboard strips. The circle should be just small enough to fit in the tuna can. One strip should be about the length of the circumference of the can, and the other strip should be just over an inch long. The strips should be as wide as half the can's depth.
Bend the longer strip into a circular loop, making its diameter 1/2 inch less than the circle. Glue the circle to the loop.
Cut two short slits on opposite sides of the loop.
Form the other strip into a loop about 1/2 inch in diameter. Glue it to the opposite side of the circle.
Poke a hole in the side of the smaller loop, and use a fastener to attach a rubber band to the loop.
Poke two holes in the can's side, across from each other. Enlarge the holes enough for the cord.
Thread the earphone cord through both holes in the can, output end first, until the center of the cord is in the center of the can.
Insert the middle of the cord into the slits in the reel and put the reel in the can.
Wind the cord reel counterclockwise, firmly holding the reel in the can. Retract the cord to its desired minimum length.
Holding the cord reel in place, wind the rubber band around the reel lightly, and stretch it to the side of the can. Mark the place where it touches the side, near the lip of the can.
Drill a hole at the place you marked. Use a fastener at the hole to secure the rubber band to the side of the can.
Tape the lid back onto the can.
To operate the cord retractor, pull the cord out and secure it with a binder clip. Release the clip and the cord will retract back in.
If you don't want to make a retractor yourself, SlingBack retractors are another option. At the time of publication, they had not yet hit the market.