Step 3: Sew your power supply and LilyPad to your jacket . First, trim the leads off of the back of the power supply Get out your LilyPad power supply piece and trim the metal parts that are sticking out the back of it. Small clippers like the ones shown in the photo work well, but you can also use scissors. Stabilize your battery on the fabric. Generally, you want to do everything you can to keep the power supply from moving around on the fabric. I recommend gluing or sewing the battery down before starting on the rest of the project. You may also want to glue or sew something underneath the power supply to help prevent it from pulling on the fabric and bouncing around as you move. If you are working on a thin or stretch piece of fabric--first of all, reconsider this choice! It's much easier to work on a heavy piece of non-stretchy fabric. If you are determined to forge ahead with a delicate fabric, choose the location for your power supply wisely. It's the heaviest electronic module, so put it somewhere where it will not distort the fabric too badly. definitely glue or sew something underneath the power supply. Sew the + petal of the power supply down to your garment. If you are new to sewing, check out this great introduction before you start for info on how to thread a needle, tie knots and make stitches. Cut a 3-4 foot length of conductive thread. Thread your needle, pulling enough of the thread through the needle that it will not fall out easily. Tie a knot at the end of the longer length of thread. Do not cut the thread too close to the knot or it will quickly unravel. Coming from the back of the fabric to the front, poke the needle into the fabric right next to the + petal on the power supply and then, from the front of the fabric, pull it through. The knot at the end of the thread will keep the thread from pulling out of the fabric. Now make a stitch going into the hole in the hole in the + petal on the power supply. Do this several more times, looping around from the back of the fabric to the front, going through the + petal each time. Pay special attention to this stitching. It is the most important connection that you'll sew in your project. You want to make sure you get excellent contact between the petals on the power supply and your conductive thread. Go through the hole several times (at least 5) with your stitching. Keep sewing until you can't get your needle through anymore. Do not cut your thread, just proceed to the next step. Sew from the battery to the LilyPad. Once you've sewn the + petal of the battery down, make small neat stitches to the + petal of your LilyPad. I used a jacket with a fleece lining and stitched only through the inner fleece lining so that no stitches were visible on the outside of the jacket. Sew the + petal of your LilyPad down, finishing the connection. When you reach the LilyPad, sew the + petal down to the fabric with the conductive thread. Just like you were with the battery petal, you want to be extra careful to get a robust connection here. This stitching is making the electrical connection between your power supply and LilyPad. When you are done with this attachment, sew away from the LilyPad about an inch along your stitching, tie a knot, and cut your thread about an inch away from the knot so that your knot won't come untied. Put fabric glue on each of your knots to keep them from unraveling. Once the glue dries, trim the thread close to each knot.
http://www.instructables.com/id/20-Unbelievable-Arduino-Projects/