Monitoring and pH regulation in urban hydroponic systems

An advantage of hydroponic systems is their adaptability to small spaces as home, especially the Nutrient Film Technique (NFT) based on hydroponic systems that can be incorporated into the urban environment. This paper presents the study of the feasibility to implement an automatic regulation of the pH into a home NFT hydroponic systems where nonhazardous substances such as acetic acid and baking soda are employ to the pH regulation. For this purpose, a fuzzy controller with Mamdani's inferences is tested to regulate the pH of the irrigation water. Also, a Kalman filter is used to get an adequate measurement of the pH sensor signal and level sensor signal. The chosen crop for the implementation is the Lactuca Sativa variety ‘Italian Red (RugbySky)’. Besides, a monitoring of the variables pH, electroconductivity and volume is made in two prototypes of the NFT system, one system, the “NFT controlled system” and the other system, called the “NFT system free”. Results of the experiments with the Mamdani's controller (for pH control and for the NFT system free), and a discussion over the obtained performance will be given.