Stitch any loose wires into your hoodie's seams. Sew a little pocket for the battery near the switch.
Add lining to cover up the wires and the back of the buttons and microcontroller, leaving open at the bottom so you can get to the USB port for programming, or easily access the wires for repairs.
I also added a layer of lining along the inside of the tail so the wires won't catch on my pants.
Put it on and turn up the music in your living room. Dance around! Move and stretch and jump and wiggle. Sweat! Try to shake out all the bugs while you're still at home with your soldering iron. Fix the parts that break.
Care and Feeding
As with any complicated project, this hoodie will need maintenance. Wires will break, buttons will come loose, and LED strands will get sat upon and squished. Kids, those loveable little forces of destruction, absolutely love to push on the buttons as hard as they can.
Be sure to have a repair kit with you if you're going to a festival or on a trip with your hoodie. A butane-powered soldering iron and some extra wire will save your lights again and again. I also carry some glue and some electrical tape whenever I'm headed out.
Don't forget the spare batteries as well!