Intro: Christmas Circuit Card
Machine stitching conductive thread to create a simple circuit on my Christmas card. The conductive thread stitches connect a 3V button battery with an LED. Two loose ends create a simple switch that can be closed by tying them into a bow.
While this version of the card requires the recipient to own or purchase two crocodile clip connectors, I created a simple battery holder in later versions by crossing the two strips of conductive tape and sandwiching the 3V button battery in between.
Please see illustration for optimal solution (though it does not correspond exactly with the photos I took of my first example) >> Download illustration
I reproduced this Christmas card 20 times, mailed them out from Austria and hope that they all arrived.
Step 1: Materials and Tools
- Conductive thread from http://www.sparkfun.com or http://www.lessemf.com
also see http://cnmat.berkeley.edu/resource/conductive_thread
- Conductive tape from http://wwwl.essemf.com
- 3V button battery (and holder)
- Crocodile clips
- Regular colored thread
- Nice colored cardboard
- Decorative pens
- Scissors or cutting knife and mat
- Sewing machine
Step 2: Cutting, Drawing and Sticking
Cut your coloured cardboard to shape (aprox. 17 x 22 cm). Fold in half and draw a Christmas tree on the right side of the front side. The circle with an X inside is the electrical symbol for a light.
Cut two small tabs of conductive tape (aprox. 1 x 1 cm) and tape them to the bottom left on the back side (not like in the photos, where I taped it to the front side where the conductive stitch is not).
Step 3: Sewing
Thread your sewing machine with regular colourful thread at the top and conductive thread in the bottom bobbin. Set to regular straight stitch, maybe about 2mm spacing.
Starting from the bottom conductive tab stitch back and forth and then across to the Christmas tree trunk and then up to the top and end the stitch by doubling back on yourself at least once.
Start the stitch again about 0,5 1 cm to the left of where you just ended it. Sew to the left back towards the upper conductive tab and in between create another gap by ending and re-starting the conductive stitch.
Now you can clip off all the loose threads, EXCEPT those of the switch. Here you can clip the non-conductive regular thread but not the loose conductive threads. These must be brought to the front side of the card and tied to a bow. To close the switch and complete the flow of electricity though the LED.
Step 4: Set-up
Now the card is finished. It is up to you weather you include a 9V battery and LED with each of your cards or expect the recipients to organize these themselves. In my case I only included a battery and LED in the cards that I did not have delivered via the postal service.
Insert the legs of the LED into the stitch holes at the top of the Christmas tree. Make sure that the legs are making contact with the conductive thread and bend them if necessary (see photos).
Clip the crocodile clips to the conductive tabs and connect them to the right side of the battery, depending on how you inserted your LED (just try which way round works).
To turn off the light undo the bow, remove the LED or unclip a crocodile clip.