Medidor de umidade de grãos com interface de usuário utilizando protocolos de comunicação para Internet das Coisas

Abstract

The post-harvest process of grains is an activity of the Brazilian agribusiness and features a series of technological challenges. Amongst those challenges, the search for suitable solutions to reduce losses associated with incorrect grain moisture control, either for commercialization and storage, stands out. With the approval of the Metrological Technical Regulation present in the INMETRO Ordinance No. 402, of August 15, 2013, commercial moisture meters are now regulated. After the approval of the MTR, the oldest and unregulated moisture meters were prohibited for use in commercial transactions, which mainly affects small grain producers, because the approved ones are sold at a high cost. This project aims to propose a solution to this particular issue, presenting the development of a low cost grain moisture meter, with an interface using Internet of Things comunnication protocols. An exploratory study on the physical-chemical composition of grains is presented, as well as explanations about the communication protocols most commonly used in systems with Internet of Things. A concentric cylinder capacitive sensor was developed, coupled to an oscillator circuit, based on a CI of the 555 family. Texas Instruments CC2650 launchpads were used: one to read the frequencies and another one as border router. The frequency data read is published at the created topic. The application developed in Flutter subscribes to that topic, receives the frequency data, performs the calculations and presents the moisture content on the screen of a smartphone. The system was developed to allows the reading of the moisture content of two species of grains, rice and corn. The data from conducted calibration tests were collected and analyzed. Has been concluded with this analysis that the developed system complies with the requirements of the MTR.