RGB LED electronic brooch. Very simple to make and fun to play with.
The project combined of basic shapes and electronics and mainly created to be an easy tutorial for a soft circuit that can be modified and expended.

Step 1: Materials and Tools

Materials

1. Non-conductive fabric: can be any sort of standard non-conductive fabric, very small piece is needed therefore I would look for some old clothing or some fabric left-overs.

2. Conductive fabric and conductive thread
There are many kinds of conductive fabrics and threads might be found. I'm using ArgenMesh fabric and a Silver Plated Nylon thread and I got it from www.lessemf.com.

3. RGB LED with a common cathode. I got it from www.superbrightleds.com, part #RL5-RGB-C

4. Craft & Fabric glue

5. 3v Lithium Coin Cell Battery (I got mine at RadioShack)

5. Sewing snaps (can be purchased at most of the fabric stores, I got mine from Mood Fabrics)

6. Printed pattern (the pdf file is attached further)

Tools:

1. Sewing needle

2. Sewing machine (optional)

3. Scissors

4. Ruler

5. Needle nose pliers

6. Multimeter

Step 2: Download, Print and Cut

Download the pdf with a sewing pattern, although you can just cut the fabric directly by measuring 5x5cm for 4 identical squares for the main parts of the brooch and 2 1x1cm squares of the conductive fabric.

RGBLEDBrooch.pdf
Download

Step 3: Cut the Fabric

Cut the fabric accordingly to the pattern or your marks.
Cut from a different color fabric little leafs to decorate your brooch. Another way to decorate it might be using a colorful decorative thread.

Step 4: Glue

1. Glue with the fabric glue the little conductive fabric squares in the middle of tow of the bigger squares as it appears on the pictures.
2. Take third square and cut a hole in the middle of it (it will used for the LED), around this hole glue the leafs in shape of a flower or any other shape that will desire to.

Step 5: Battery Holder

Now the most complicated part of this project is the battery holder:
1. Take the two squares that you just glued the conductive fabric on them.
2. Thread the needle with the conductive thread. Pick one of these squares and make several stitches on the conductive fabric piece, don't cut the thread.
3. Take the female part of the sewing snap and sew it on the opposite side from of the square with the same thread without cutting it.
4. Take the second square with the conductive fabric and make several stitches on the conductive fabric square. Pull out the needle but don't cut the thread, leave a long piece of it hanging. You will be using it later.
5. Go back to the first square and sew the 3 other female snaps on the 3 corners (as shown in the picture). For these pins use a regular thread.
6. Now the tricky part: take the second square thread it with the conductive thread that you left hanging on it, make a few stitches towards the edge of the square.
7. Take the other square and by sewing these two together add the 4th female pin to the 4th last corner.
8. After you done, take out the multimeter and check the conductivity between the conductive fabric little squares and the snaps that connected to them.
9. Now just sew the both pieces together but leave one side open, you will get a little pocket.
10. The last step is create a a little stitch in the form of the battery to keep it tight on the conductive fabric. The best way to do it is to put the battery inside the pocket, holding it against a light source to see better where to place it. Don't close the stitch, leave space to insert the battery, as shown in the picture.

Step 6: Sewing the LED

1. First of all mark with a short piece of thread the cathode leg of the LED. (It's the longest leg)
2, Use the needle nose pliers to bend all the four legs in sort of little circles (see picture).
3. Use conductive thread to sew the cathode leg in the middle of the last remaining fabric square.
Without cutting the conductive thread sew a male snap in the middle of the back side of that square.
4. Spread the other 3 RGB legs facing each one different corner of the square.
5. Sew with the conductive thread each of the legs to the square and the make a few other stitches to get closer to the corner. Without cutting the conductive thread sew a male snap at the corner on the back.
6. Do cut the conductive thread each time when you sewing another LED leg and it's male snap.
7. At the back of the remaining forth corner, sew with a regular thread a male snap, not connected to any of the LED's legs.
8. Use the multimeter to check the conductivity between each LED and the male snap that attached to it.
10. Now take the last square of fabric with the glued flower on it and sew it to the LED square. (see picture).

Step 7: Final Step

That's all, you are done!

Attach the male snaps to the female snaps and see how the LED lights up. Rotate the flower and attached the snaps again the LED will change the color.

That's all hope the explanations are clear, but I tried to provide detailed picture. It is a very simple example and any modification on it will be great.