I made this using an Adafruit Gemma M0 and their MEMS microphone. I designed the fabric myself and had it printed at spoonflower, the pattern I used for the dress is McCall’s M6028 and I highly recommend it since it has an amazing fit :3

The directions for sewing on the LEDs are simple enough and pretty much electronics 101. You have to make sure they get juice, so they have a (+)-circuit and they need ground via (-)-circuit. You don’t have to connect these two in series but can make several "power circuits" so to say. Sometimes it's even adviseable, e.g. if the voltage you get at the middle of your circuit is not enough you can add a cable from (+) directly to there. It is important to do some layout planning ahead so you won’t have short circuits because of crossing +/-/Data-circuits (that’s why there is some black isolating tape around some wires close to the gemma on my dress). The data-circuit is the only one that is required to be “in order”; -> to -> strictly. To prevent issues due to sweating I recommend to add another layer (or several layers) of fabric between the circuits and your skin. Also the wire is pretty scratchy. This also does make it prone to “friction holes” in the fabric, so you might want to choose your fabric accordingly. I sealed the ends of the "wire thread" in place with hot glue, there might be more elegant solutions than that but it works fine. 

I did the sewing and my boyfriend had to do the programming again. I myself have never evolved beyond programming simple blinking lights and the integration of the microphone and making the LEDs “react” to the volume is way too complex for me. Basically it circles a color wheel and then turns the LEDs on/off corresponding to the volume. We had a few problems this time because the microphone is actually “smarter” than expected and corrects the gain - I hope I’m expressing this correctly - in loud environments automatically, thus leading to having my boyfriend to calibrate it and change stuff in the code multiple times. In retrospect the microphone we used for the v1 would work probably better and I’m possibly gonna harvest the v1s remains (it died of developing a short circuit because of too narrow a sewing pattern, a design mistake I didn’t repeat this time - I hope) and might exchange them later.

Thanks for the full body picture goes to Sascha Ludwig for being my spontaneous photographer :3