Mini computer: The tiny KL02 microcontroller, made by Freescale, was created to enable swallowable wireless computers, and contains an energy efficient processor, memory, and RAM.

Read more: http://www.technologyreview.com/news/514101/wanted-for-the-internet-of-things-ant-sized-computers/#ixzz2V1JeGDvp
I wonder what operating system it runs?