make your own electronic sewing kit
(no previous electronics knowledge or soldering required)

   

left: a shirt decorated with LEDs and fabric switches.
right: a homemade headlamp with LEDs sewn into a stretchy headband.



These instructions will teach you how make your own "electronic fashion" by sewing lights and other electrical components into fabric with conductive thread. In the course of describing how to make the tank top shown above, they will introduce materials and techniques that can be combined to build a general purpose electronic sewing kit.


what you will need:
  • a piece of fabric or item of clothing
  • conductive thread and a needle
    (You can purchase spun stainless steel thread from Lame Lifesaver.
    Check out my materials link page for more information.)
  • lights: Light Emitting Diodes (LEDs)
  • 2 AA batteries
  • a battery holder for 2 AA batteries and snap-on leads for the holder
  • wire strippers
  • needle-nosed pliers
  • netting material (optional - for fabric switch)
  • a piece of felt or wool (optional - for fabric switch)
  • sewing machine (optional)
  • multi-meter (optional)
  • conductive fabric (optional)
    (You can purchase an assortment of conductive fabrics from Less EMF.
    Check out my materials link page for more information.)
  • soldering iron and lead-free solder (optional)
  • advanced optional: the sky's the limit! add microcontrollers, sensors and actuators to your heart's content.

  • Where to get electrical supplies: You can get LEDs, batteries, battery holders, wire strippers, pliers, multi-meters, soldering irons, and other electronic supplies from your local RadioShack. In the back of most stores there's an electronic hobby selection. Ask a salesperson if you have trouble finding it. A salesperson should also be able to help you find all the electrical supplies on this list. For a larger selection of LEDs and other electronics check out Digikey online.

   

left: Light Emitting Diodes (LEDs).
right: a battery holder for 2 AA batteries and snap-on leads.





some of the other supplies you'll need: pliers, wire strippers, scissors, needles and conductive thread.


a little about circuits and LEDs
If you are completely new to circuits, you should read enough to understand how a basic circuit works before embarking on this project. Introductions to electricity and circuits can be found at: Electronics Club - Electricity and the Electron and Doctronics - Circuits.

Light Emitting Diodes (LEDs) are special types of lights. An LED shines when electricity passes through it in the correct direction. LEDs usually have two "leads" or wires coming off of them. One lead is the positive (+) end of the LED, called the "anode", and one lead is the negative (-) end of the LED, called the "cathode". In the picture above, you can see that for each LED one lead is longer than the other. The longer lead is usually the anode lead. If you are new to LEDs, you should read the first section of the page at: Electronics Club - Light Emitting Diodes (LEDs) before proceeding.

A note about LEDs and resistors. Generally, you have to be careful not to attach an LED directly to a power supply. Attaching an LED directly to a power supply can cause the LED to burn up as too much electrical current flows through it. Normally, you have to attach an LED to a power supply through an electrical component called a resistor. However, for the project described here we will not need resistors because we will use a fairly weak power supply of 2 AA batteries (these will supply 1.5 volts + 1.5 volts = 3 volts) and the conductive thread we will use to sew out our circuit has some natural resistance and thus functions like a resistor. IF YOU USE A DIFFERENT POWER SUPPLY FOR THIS PROJECT OR DO ANY OTHER ELECTRICAL PROJECTS INVOLVING LEDs YOU NEED TO USE RESISTORS IN YOUR CIRCUITS TO PREVENT BURNING UP YOUR LEDs! For more information on resistors and LEDs see Electronics Club - Light Emitting Diodes (LEDs).

design
1. Pick a garment or piece of fabric to sew on.

2. Design your circuit. Decide on the number of LEDs you want and their placement. Also decide where you're going to put your power supply. I decided to sew four LEDs and four fabric switches into a tank top and to place my power supply close to the edge of my shirt so that I could carry the batteries around in my pocket. Whenever a switch is pressed, the LED attached to it will turn on. (For a simpler design, remove the switches - then all four LEDs will be on all of the time) Here's my design:

   

left: my design for a tank top with four LEDs. (click on the image for bigger picture.)
right: a schematic diagram of the design.
to learn how to read schematics check out Electronics Club - Circuit Symbols.



A note about designing: You should plan a circuit which leads from the positive end of your power supply through an LED and then back to the negative end of your power supply. You can attach more than one LED, but because we are using a fairly weak power supply (only 3 volts), each LED must be connected directly to the power supply. The LEDs need to be configured in what is called a parallel circuit and cannot be configured in what is called a series circuit. If you put several LEDs into a series configuration, you will need a stronger power supply. For more information on series and parallel circuits check out Electronics Club - Series and Parallel Connections.

   
left: a parallel circuit. the + lead of each LED is attached directly to the + end of the battery and the - lead of each LED is attached directly to the - end of the battery
right: a series circuit. the LEDs are all in a row. the - lead of one LED is attached to the + lead of the next LED



3. Transfer your design to your garment or fabric. Once you have decided on a design, mark out your circuit on your garment or fabric with a fabric pen or pencil. Leave holes for the places where you will stitch in your LEDs, switches and battery holder.

construction

1. Sew your circuit, following the design you traced. If you have a sewing machine, this will go more quickly, but you can also do it by hand. If you are using a sewing machine, wind a bobbin of conductive thread and put it in the bobbin of your machine. Some conductive thread is too large to be used as top thread in a sewing machine, so this is your best bet. Follow the lines you made on your garment to stitch out the conductive traces. Again, be careful to leave space for your LEDs and other components.

   

left: conductive thread should be placed in the bobbin of your machine.
right: sewing out the traces.



2. Make your LEDs stitch-able. Get out your LEDs and pliers. Grasp one of the leads of an LED with the pliers. Using the pliers, twist the lead over on itself several times so that the lead now makes a loop. Be careful to leave some indication of which lead is + (usually the longer lead) and which is -. I do this by leaving a long tail on the + lead and clipping the tail on the - lead completely off. You can use wire cutters or a pair of strong scissors to snip off unwanted wire tails.

   

twisting the LEDs


Note, you may also want to wait to twist your LEDs until you incorporate them into your fabric design. This method will be covered in the next section.

3. Stitch in your LEDs. If you have not yet twisted your LEDs, you can hide the twisting loops on the back side of your garment or fabric. Align your LED where you want it on your garment being careful to align the + and - leads correctly with your traces. Push your LED through the fabric and twist the leads as was described above. Again, wire cutters or scissors can be used to trim off the excess wire once you're done twisting.

   

left: pushing an LED through the fabric.
right: LEDs which were pushed through the fabric and then twisted.



Thread a needle with conductive thread and, by hand, sew each LED lead to the appropriate conductive trace. The object here is to make an electrical connection between the trace and the LED lead, so be careful that the conductive thread makes good contact with both the LED lead and the conductive thread you sewed earlier. You also want to make sure you attach the proper lead to the proper trace. The + lead of an LED should be stitched to the trace which will lead to the + end of your battery and so on.

   

left: stitching in the LEDs.
right: close up of a stitched in LED.



Note: you need to force electricity to flow through each LED. If there is a length of conductive thread leading directly from the + to the - lead of an LED then electricity will flow through this thread instead of flowing through the LED and the LED won't light up. There should be nothing conductive between an LED's two leads. You need to sew each lead separately, tying off your thread in between leads.

When you have a good sturdy stitch, tie your thread in a knot and coat the knot with fabric glue before snipping your thread. Conductive thread will fray and come un-knotted easily, so this is a crucial step.



gluing a knot so that it won't fray.


4. Make your snap-on battery holder leads stitch-able. With your wire stripper, take off about an inch of the insulation on the snap on lead wires. My wire was 18 AWG, so I used the 18 AWG sized hole on my wire strippers (the holes should be labeled). Your wire is likely to be the same size.

Once you strip off the insulation, you should have about an inch of bare metal wires coming out of each of your leads. Twist each end to form a loop. Twist it several times so that you make a good strong loop. You will stitch these loops to your shirt to attach your battery, so they'll need to withstand some stress.

   

left: stripping the insulation off of the battery holder leads.
right: the snap on battery holder leads after the leads have been twisted into loops.



5. Stitch on your snap-on battery holder leads with conductive thread. You will stitch these onto the places where you left room for the battery. Stitch the red lead where the + end of the battery should go in your circuit and the black lead where the - end of the battery should go. Stitch through the loops, and again, be careful to make good connection between the leads and the conductive traces you sewed out earlier.

6. Add decoration and, if necessary, protective backings so that the twisted LED leads will not scratch your skin. I sewed patches of felt over my stitched on twisted LED leads. I also sewed felt frames around each of my LEDs for decoration.

   


left: a decorative LED frame.
right: protective backings on the inside of the shirt.



7. If you plan to add a switch to your design, proceed to the next section. Otherwise, plug in your battery and test your garment!

If your LEDs don't turn on, here are some common sources of error:
  • your LED(s) may be sewn in the wrong direction. Try flipping them around.
  • your circuit may be skipping your LED(s). make sure you're forcing current through each LED; make sure your traces never form a path around any of your LEDs
  • there may be a short in your circuit. Make sure there is no place where the trace leading directly off the + end of the battery touches the trace leading off the - end of the battery.
  • there may be a gap in your circuit. Examine each of your traces and make sure there are no broken threads or gaps in any of them. Your circuit must form at least one unbroken loop leading from the + end of the battery, through an LED and back to the - end of the battery.
  • your batteries may be bad. Try new batteries.

making a fabric switch (optional)

Note: This basic technique for building fabric switches was first described by Remi Post and Maggie Orth in their excellent paper E-Broidery: Design and fabrication of textile-based computing.

1. Cut out two patches from a thick springy material like heavy wool or felt. Cut the patches in the shape you'd like your switch to be in.

2. On each patch, sew a conductive region through the middle and leave a dangling conductive thread attached to your conductive region. Do not cover the entire patch with conductive stitching, you will need two non-conducting edges. See the picture below to get an idea of what these pieces should look like.

3. Cut out two pieces of netting roughly the size and shape of your patches, but a little bigger

   

left: components of a fabric switch.
right: sewing the switch together



4. Assemble your patch. What you want is a patch of fabric where the two conducting surfaces will contact one another when the patch is pressed, but will not contact one another otherwise. To accomplish this, we will sew the two patches and two pieces of netting together so that the conducting areas are facing one another, but perpendicular to each other, and the two pieces of netting are in between these faces. The netting will prevent contact when the switch is left alone, and allow for contact when it is pressed.

Sandwich your pieces together and sew your sandwich together. Make sure that you take the conductive thread out of your sewing machine before you do this!

5 . Test your switch. Using a multi-meter in its "beeping" mode, attach a lead of the multi-meter to each of your dangling conductive threads. The multi-meter should be silent (read "open") when the switch is left alone and beep (read "short") when it's pressed.

6. Sew your switch into your design just like you stitched in your LEDs making sure that the two ends of the switch don't contact one another.

7. Plug in your battery and test your garment. If any of your LEDs don't work, see the last part of the previous section for details on a couple of common problems and how to fix them. Enjoy your electronic fashion!

washability

Your sewn circuit is washable. Remove the battery and wash the garment by hand with a gentle detergent. Drip dry.


for more information:

For information on more sophisticated techniques, including instructions on how to attach microcontrollers to fabric, check out my make your own wearable LED display page.

Sewing Circuits: more information about the Craft Technology Group's electronic sewing workshops, a collaborative project with Nwanua Elumeze and Sue Hendrix.
SWITCH: Alison Lewis has a web broadcast of how tos intended to introduce girls to technology.
Electronic Jewelry Workshops Page: Elisabeth Sylvan conducts workshops where participants learn to make electronic jewelry
Electronics Club: an excellent electronics reference for beginners
Enlighted Designs: for inspiration, check out this site where you can order custom made LED clothing.


This material is based upon work supported by the National Science Foundation under Grant No. 0326054.

Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).