Automated Greenhouse

Sammanfattning: In agriculture, growing plants is usually done with soil asthe growing medium. An alternative method for soil is usinga hydroponic system with plants submerged in water.In this thesis, a hydroponic system was built with the purposeof finding out suitable constants and loop-time of aPID controller to reach optimal pH value for plant growthof a nutrient solution, without intoxicating it. An Arduinouno micro controller was used to turn on and off a waterpump, oxygen pump and lights at certain intervals. ApH sensor was used to measure pH-levels in a tank, givingthe output from the pH-sensor as the input for thePID-controller. Depending on the output of the PID, twoservos opened valves to release either an alkaline or acidicsolution into the water reservoir. The results of the testsconducted show that it is possible to find working constantsand loop-time for the PID to successfully reach optimal pHof the water reservoir without intoxicating it.