Hydroponic nutrient mixing system based on STM32

Abstract

Hydroponics nutrient mixing system based on STM32 is a device to produce hydroponic nutrient solution, according to individual plant nutrient recipe, automatically by using individual dosing pump for each fertilizer concentrate. Nutrient recipes and fertilizer database are stored in Raspberry PI. The system will compute the recipe and translate to the required individual concentrates' volume, then send command to dosing pump controller. Dosing pump controller will then send command to 10 dosing pump motor drivers to pump each fertilizer concentrate according to the volume measurement to produce the nutrient solution. The core of dosing pump controller is a 32bit microcontroller development board Nucleo-F446RE from ST Microelectronic, ample to control 10 dosing pump drivers. Each of the dosing pumps will be equipped with fertilizer concentration with maximum solubility. The system has user friendly graphical user interface using 7" graphics LCD. To produce specific solution strength, system can fill in water through water pump and use water level sensor to measure the volume, this process is controlled by proportional controller. The output of the mixing process can be hydroponic A and B mixed concentrate solution, or direct solution. For concentrate solution user must dilute A and B concentrate with water. The system has been tested 9 times and produce maximum 9% error. Water filling system accuracy test for 5-liter water volume with Kp 10000 has 2.784% error.