Hydroponics is a technique to grow the plant without using the soil. This technique ensures the plant gets all nutrients needed from the water solution. There are many types of hydroponics technique. The Deep Water Culture (DWC) is one of the hydroponics technique types. DWC is a technique that grows the plant by supplying the nutrient direct to the root of the plant until the plant can be harvested. By using this technique, the plant root will be always submerged into the water that contains nutrient and oxygen. However, this technique manually controlled the pH water, which can give bad effect to growing of plant. In this research, the pH level in water solution will be automatically maintained by microcontroller and measured by sensor. Next, the period of pH level started to change and the effects of pH adjuster solution to the water solution are determined. Lastly, this research also focuses on the ability of the system can adjust the pH value in water solution for DWC. The water solution from the DWC container is transferred to the main tank to measure the pH level by sensor and make adjustment if needed and then transfer back to the deep water culture container to continue growing the plant. There are six stages in methodology for this project, which are details of study, hardware identification, software identification, hardware and software interfacing, analysis and troubleshooting, data and result collection. The result from the experiment test showed that the system able to decrease the pH level by 0.58 pH and increase the pH level by 1.15 pH.
This system was used two tanks, which were main tank and hydroponics tank. The position of the hydroponics tank was placed above the main tank so that the water solution in the hydroponics tank could be easier to transfer back into the main tank for the rechecking the pH level in water solution after a certain period. By this way, to transfer the water solution into the main tank can be done by solenoid valve. It made the cost of the project can be reduced. To stand the pH adjuster dropper and stirrer, the PVC pipes were used