If I didn’t have a big house blocking my southern exposed window, otherwise I would have completely tried this myself. The basic idea is to take come recycled plastic bottles, use an air pump and some tubing to create an air water pump to push the nutrients to the top and gravity takes care of the rest.
The great part of this is that it is an open design community making and sharing new innovations as they are discovered. Here are the complete instructions of the most recent (version 3) of their system. They also offer a complete kit if you want to save some time with assembly.