Glowing Christmas Stocking With LilyPad LilyTiny

This project was originally published on Instructables. View the original project.

Add some twinkle to your holiday stockings with the LilyPad LilyTiny. The LilyTiny has four pre-set modes that you can choose from to create a 'breathing' fade, heartbeat pulse, blink, or twinkle with LEDs you connect to it. In this project you'll learn how to construct a circuit with conductive thread on the lining of the stocking, creating a seamless soft circuit project.

This is the third in my Glowing Christmas Stocking series, and it takes a little bit more planning and construction time than the Glowing Christmas Stocking with Fairy Lights and Glowing Christmas Stocking with EL Wire projects.

Materials Needed:

• Christmas Stocking - light fabrics work best for the LEDs to shine through

• LilyPad LilyTiny

• LilyPad Simple Power

• LilyPad LEDs - the number will depend on your design. I chose white, but they are available in red, green, blue, yellow, and pink as well.

• Conductive thread

• Micro USB power cable (and wall adapter if not attached)

• Alligator clips (for planning and testing your project)

Optional: 3.7V LiPo battery (if you want a cord-free look)

• Needle

• Sewing thread

• Sewing Pins

• Scissors

• Fray check or clear nail polish

• Paper and pens for sketching your design

Optional: Scrap fabric to make a battery pocket

Parts of the Circuit:

The LilyTiny connects to the LilyPad Simple Power through the + and - tabs. The + tab of the LEDs will connect to one of the numbered (0-3) sew tabs on the LilyTiny and the - tabs will all connect together back to the - tab of the LilyTiny or the LilyPad Simple Power.

If this is your first time working with LilyPad electronics and conductive thread, here are some resources for you:

• LilyPad Basics: E-Sewing

• LilyPad Simple Power Hookup Guide

• Powering LilyPad LEDs

Step 1: Prepare Stocking and Prototype Circuit

Carefully open the seam on three sides of the stocking so you can separate the front from the back. Then, if needed, open up the seam between the top layer and lining of the front of the stocking. The electronics will be installed in the front lining.

Quick Prototyping for Placement:

The Simple Power board has two ports: one for a micro USB cable and another for attaching a LiPo battery. Plug either the battery or cable into the proper port. Make sure the switch is set to OFF. Attach an alligator clip to each of the sew tabs and to the matching tab on an LED. After everything is connected, turn the Simple Power board on.

The LED should light up - move the LED under the top fabric of the stocking to decide where you want it to shine through in the final placement. Use a marker or pen to note where to attach the LEDs during construction.

At this point, if you want to try out what each of the modes on the LilyTiny do, you can hook the circuit up with alligator clips. With the Simple Power turned off, unclip the LED and clip the + tab to one of the numbered tabs on the LilyTiny. Clip the - tab of the LilyTiny to the - tab of the Simple Power and the + tab of the LilyTiny to the + tab of the Simple Power. Finally, clip the - tab of the LED to the - tab of the LilyTiny. Turn the power on to see the LED effect for that tab. Unclip and reclip the LED to the other tabs to try them out.

Sketch Your Final Design:

After you've decided on the sew tab you want to connect to and where the LEDs, Simple Power board, and LilyTiny will be placed, sketch your final design on a piece of paper. Label the + and - tabs and any notes you want to capture before doing your final hardware install. At this stage, you can check to make sure that no stitch lines cross to cause short circuits and that all the hardware is in a logical place for your design.

For my project, I kept the LilyTiny close to the top left edge of the stocking with the + and - tabs facing the left edge. This allows me to place the Simple Power board on the back of the stocking for easy access to the on/off switch and battery attachments. The numbered sew tabs are angled toward the rest of the stocking to make it easy to bring the stitching around to them. I am going to be stitching to tab 3, which has a twinkle effect.

Step 2: Attach Hardware

Place the LilyPad pieces on the stocking according to your diagram. Double check the alignment, then use a dab of hot glue on the back of the pieces to attach to the lining of the stocking.

Use a marker to draw your stitch lines if you'd like to help keep your stitching on track while working.

Step 3: Stitch Circuit

When you are ready to start stitching components together, begin on the sew tab of one of the boards and loop around the tab with 3-4 tight stitches. Continue with a running stitch to the next board in your circuit and loop 3-4 times around the tab you are connecting. Tie a knot and cut the thread, snip any conductive thread tails close to the fabric. You can also seal the knot with fray check or clear nail polish. For tips on sewing with conductive thread, check out SparkFun's LilyPad Basics: E-Sewing guide.

If you are connecting all of the LEDs to one sew tab so they light up simultaneously, you can use one length of thread to connect them all, using 3-4 loops around the tabs and then continuing on to the next LED. If you run out of thread, simple stitch over existing stitches to connect and continue. The thread is uninsulated so it is easy to join two stitch lines together. Keep this in mind for stitching you don't want to touch as stitching too close to another line of stitching can accidentally connect.

To attach the Simple Power board to the LilyTiny, I stitched across the side seam and underneath the top layer of fabric on the front side.

Step 4: Insulate Circuit

After all of the stitching is completed, power on your circuit and test. If some LEDs aren't lighting up, test to see if the stitching around the tabs is too loose. You can also check for loose thread tails touching another part of the circuit or broken stitches. Check out the troubleshooting section of SparkFun's LilyPad Basics: E-Sewing guide for more tips.

Once your circuit is tested and working, turn the power off and insulate the stitching with fabric paint or glue (I used Aleen's Tacky Glue). This will protect the circuit from wear and tear, accidental movement of the fabric causing stitch lines to touch, or metal pieces of the presents you put in there from shorting out the thread. Set aside to dry.

Step 5: Finishing Touches

After the insulating material is dry, pin the stocking back together and restitch the seams with sewing thread.

The Simple Power board has a charge light may be distracting on the back of your project. You can paint or tape over it if desired. Make sure the power is disconnected when painting until it is dry.

If using a LiPo battery: to hold and protect the battery, you can glue a piece of felt on the back of the stocking to act as a pocket. Be careful not to glue while the battery is in there as heat can damage a LiPo. To further reduce strain on the battery's wires, you can use electrical tape around it as shown.

Hang up and enjoy the sparkle!