Your best bet for building your own is going to be a combo aero/hydroponics unit like the one mentioned above, and most on this site. True aeroponics devices use sprayers to get the smallest water particles possible, and many of them. The roots are then suspended in air, with these sprayers spraying nute solution on them. This requires a good pump, some sprayer tips that can guarantee a tiny particle size, and a water tight, light proof chamber that they spray in. Apparently people here have ahd great luck using a DWC bubbler system, which you can find directions to build on this site. Good luck.
