Desenvolvimento e calibração de um protótipo de sensor de umidade do solo para aplicação em sistemas de irrigação

Abstract

The importance of water in agriculture for the success of crops is unquestionable. In the present times, irrigation has become a strategic tool for the success of productions. Among other benefits is the possibility of planting between harvests, which makes it possible to improve the utilization of the agricultural area. Higher productivity can also be achieved through the artificial use of water to the crops. However, a balance must be struck between the interests of production and the socio-environmental criteria. Also, the availability of water in excess can lead to damages, causing the proliferation of fungi and bacteria, and the possible rotting of the roots. In this way, irrigation of crops should demand efficient controls of soil water content, emphasizing the rational and ecologically sustainable use of the natural resources involved. It is known that there are several soil moisture sensors that are able to obtain the water content in the soil, and that can aid in the control of water use. However, the high costs of quality sensors continue to be a barrier to the implantation in crops of small producers, due to their fragile purchasing power. Motivated by this, this work sought to develop a prototype sensor that would allow the measurement of soil moisture, and the main premise would be the low cost. For this, it was necessary to carry out the calibration of the prototype, from simultaneous readings between the same and the reference equipment, the professional sensor Watermark model 200SS-5. Of accessory form, the prototype was designed to communicate with external platforms, possibiliting the integration and real-time monitoring. For the database the data were transmitted through the wireless technology of the ESP8266-12E microcontroller (NodeMCU board). Two platforms were used, the ThingSpeak, as well a another developed by this author for the specific purpose of integration with the prototype. The cost for the prototype development corresponded to 4.2% of the value corresponding to the Watermark sensor, having additional characteristics compared to the reference equipment, the such as communication with external means and the easy integration with automated irrigation systems.