Hi, I have been working on some wearable concepts for a while now. A main component has been flexible PCB. To minimize traces and complexity, I have made several reusable modules and put them up on
http://hackaday.io/project/2236-Flex-Modules . I am curious for input on the concept and if anyone would be interested in contributing or had ideas for more modules. I picked the STM32F401 as the main microcontroller and include an nRF51822 in the designs for Bluetooth or use by itself if you don't need an M4.