Basic Sewable Circuit

Combine a battery and LED light with conductive thread to make a basic sewable soft circuit on felt.

GATHER MATERIALS: (Vendors – Sparkfun, Adafruit, Amazon)

  • LED lights with resistors
  • battery (3 volt CR2032 coin size)
  • conductive thread (stainless steel thread)
  • scissors
  • round-nose pliers (to coil ends of LED resistors)
  • sewing needle (self-threading needles work best)
  • felt fabric
  • assorted sewing notions (fabric pencils, buttons, scrap fabric, sequins, regular sewing thread, etc.)

PART ONE – PLAN THE BASIC SOFT CIRCUIT:

  1. Draw on paper to plan your design. Indicate placement for the battery and LED light and where the conductive thread will connect the components.
    1. Remember you will use one piece of conductive thread to connect “+” sides and a separate piece to connect “-” sides.
    2. Do not cross the positive and negative lines of conductive thread.
    3. Consider how you can use regular thread to complete non-conductive aspects of your design.
  2. Lay out your materials.
  3. Test batteries and LED light to ensure they work.

THINK ABOUT: How can the design use as little conductive thread as possible and still maintain a balance of conductivity and aesthetics?

PART TWO – MAKE THE FABRIC BATTERY POUCH: (There are sewable battery holders that you can purchase, but they are often too expensive to use with large groups.)

  1. Cut two squares of fabric (slightly larger than battery).
  2. Sew a small circle of conductive thread in center of each square (about ¼ or ½ size of battery).
  3. Use regular thread to stitch three sides of squares into a pouch (leaving one side open for access).
  4. Test to make sure battery fits. Make sure battery is accessible for replacement. Used batteries cannot be thrown in regular trash and must be disposed of properly.

THINK ABOUT: How much conductive thread is needed to ensure maximum power from the battery pouch?

PART THREE – SEW THE BASIC CIRCUIT:

  1. Mark the longer “+” lead of the LED light(s) with Sharpie marker.
  2. Coil resistor ends of LED light(s) into sewable circles.
  3. Sew components onto fabric. Remember to use separate pieces of conductive thread for “+” and “-” connections.
  4. Secure ends with hot glue.

THINK ABOUT: How can you insulate the conductive thread without compromising the aesthetics of the design?

EXPERIMENT CONSIDERATIONS:

  • How can you create an on/off switch to save the battery power?
  • How many LEDs can you power with one battery? What other types of circuit designs can you use to power more than one component?
  • How can you use more fabric and conductive thread to create a switch that turns the circuit on and off?
  • What other conductive materials can you use to make the sewable circuit interactive?