I guess its not meant to be easy, but thats not why we do this, we do it because its hard...
I do not expect to succeed at first try, (even though theres no reason why not except a million), but First of all I need to have control on the conductivity in the water and the Ph. Thats the two main sensors in the system. Here I may use technology from Aquariums. Found the following project for ardunio: **broken link removed**
They use standard Ph and conductivity sensors and it is what I was looking for as a starter and theres a ton of these sensors at ebay to look at, in addition I need temperature sensors and moisture sensors inside the Aeroponics chamber (it will give a clue if the roots a re dry or not.) as a minimum. Then of-course there is motor controller to the pump which should have a backup pump to fall in if the main pump fails. One of the most common source of failure with Aeroponics is pump failure with the following root dryout.
To prevent root dryout one could also use high pressure foggers. The dropplets will have a higher speed and this will ensure that the entire root bundle gets wetted into the very center of the bundle and not only the outside of the bundle which might be the cause if using low pressure. However, the nozzles are more expensive and have a higher failrate.
Lots to think of, as you may see, but fun.... for now atleast