Luka (15) is not the ideal plant keeper and so he wanted to change that. Besides, it is very convenient for people in the cities to grow their own vegetable gardens in their apartments or balconies. He used Arduino and a couple of other components to build a system that measures data such as moisture and temperature of the air, the moisture of the soil, power of sunlight. The system looks after watering the plants and presents the data to the user.
To build an autonomous system you need to first think about the biological aspects. In order to automatize something, you need to research the needs of the plants to grow, develop, and adapt the system for it.
Besides measuring the levels of CO2 and oxygen there are also other variables in the world of plants and biology. One of the core elements for growth is water. And this is where most of the work regarding a plant comes: watering. Luka decided to integrate a moisture sensor into the soil to measure it. With this value, we are able to recognize when a plant needs watering, and when there is enough water. To build a 100% reliable system and avoid problems, Luka decided to use 2 sensors. Using the Arduino microcontroller he built a simple system. Arduino constantly reads the data of moisture provided by the 2 sensors and evaluates these values.
He watered the plants perfectly and so he was able to read the values measured by the 2 sensors. Using programming skills he created a simple program in C++ with the Arduino book. The aim of this program is to check the level of moisture in the soil and if the level drops below a certain value, previously measured, it should trigger a relay (Relay is an electrically operated switch). He connected the water pump to a relay, that has a water conduit from a tank. So if the level of moisture drops below the optimal value, the system will trigger and start watering the plant until watered perfectly.
However, Luka wanted to do and learn more. The data such as temperature, moisture, sunlight etc are all very important also for the plant to develop and function. Therefore he decided, that he wants to send all these data to the system user.
For the recognition of the air moisture and temperature he built in the DHT22 sensor. For the recognition of sunlight intensity he used a simple photoresistor. Then he faced a question how to pass these data to the user. He got the idea inspired by a mobile phone. He integrated 16x2 LCD screen into the whole system through which we can browse the menu to check all sorts of data from the system. This process was followed by a lot of programming, not Luka's favourite task. However, he made it in about 3 days. After that the 3D modelling of the frame for all the electronic components started and 3D printing of the system for water storage. 3D printing is a very quick and interesting way to make simple prototyping cases.
Working on this project Luka learned a lot of practical, useful things and approaches, like learning to fail and develop patience for loads of troubleshooting. ''Creation of this kind of projects is a train of emotion – from joy to sadness and tears and everything in-between.''
The system can be based on all sorts of inputs with the help of outputs, take care of the growth and activty of the plant. It is an ideal product that can help families grow vegetables, herbs and flowers in the cities. The core values are that the system is reliable, useful, autonomus, safe, compact and visualy appealing. It is also portable and adjustable and can be used anywhere from gardens, roofs, balconies and even inside of our homes.