Garden watering system based on moisture sensing

Garden centres supply many different plants which will have varying watering needs. Each plant must receive the correct amount of water. Too much water may starve the plant´s roots of oxygen and cause them to rot; too less water and the plant will not receive the nutrients in needs to survive. A garden centre must cater to each plant´s watering needs in order to maintain a high level of health in their plants. Currently, many garden centres use a timer-controlled sprinkler system to water their plants. This has a disadvantage in that the timer system has no means of measuring the moisture level of the soil, which may lead to over-watering of certain plants. This paper presents a system that is capable of measuring the amount of moisture in the soil and determining whether or not the soil required water. The system utilizes a Dual Output Tap Timer, consisting of two motorized water valves, to simulate a garden centre´s sprinkler system. A Teensy 2.0 microcontroller acted as the control system, controlling the motorized valves and reading signals from two simple moisture sensing circuits. The testing of the system proved that plants can be watered based on the moisture level of the soil. It also showed that the soil probes needed to be much more reliable in order for the system to be successful.