The hydroponic system I use is based on the Kratky method which allows any vegetable to grow in the system without the need for pumps that re-circulate the water or oxygenate it since the plant begins to absorb the nutrients from the water, consuming the level of it thus achieving a space that allows it to absorb oxygen from the environment.

        For simulation and practical purpose I created this prototype including a re-circulating pump and sensors to study various hydroponic techniques more closely.

The prototype allows to automate the start and end of the re-circulation of the water to distribute the nutrients and allow all the plants to absorb them equally by means of a 5v submersible pump. It also has a lamp with 15 LEDs (10 red 5 blue).       
 
To obtain information on water quality, I measure its parameters (PH, TDS and OD) with analog sensors connected to the inputs of the TXT Controller. The water temperature is measure with a waterproof NTC Termo-resistor

Full Link