So you want to create a smarter sweater? Adafruit has shared a guide that shows you how to make your own LED Matrix Snowflake Sweater with Bluetooth control. You will be able to display snowflakes in your sweater and control the animation and color using the Adafruit Bluefruit LE Connect app on your iOS or Android device.
You are going to need a flexible 8x8 NeoPixel matrix, a Feather 32u4 Bluetfruit LE, a battery, and an extension cable. The wonderful Becky Stern has shared more information and the code for this project here.