Electronic Measurement System for IoT Sensors Studying

Abstract

The paper substantiates the choice of methodology and develops an electronic measuring system that provides opportunities to study the sensors of Internet of Things systems. Based on the analysis of existing methods of building similar systems, we chose an approach and offered a method of ensuring the given level of temperature and humidity in the climate chamber. In particular, the determination of the level of relative humidity for its further regulation is carried out using a reference sensor of relative humidity and temperature. The parameters of the sensor studied by the students are determined based on the measurement of the frequency of the generator built using the NE555 chip. The necessary humidity level in the climatic chamber is maintained by mixing wet and dry air, which flows are regulated by valves of different diameters. The developed electronic measuring system was manufactured, and its experimental testing was carried out. The experimental results of the dependence of the humidity in the climate chamber, measured using the reference sensor DHT22, on the ratio of the areas of the holes in the valves indicate its nonlinearity. At the same time, the dependence of the frequency of generated oscillations and the capacity of the analog capacitive humidity sensor on the relative humidity in the climate chamber is practically linear. According to the results of the experiments we obtained an empirical formula, taken into account when programming the device and intended for further measurements of relative humidity. The main characteristics of the developed electronic measuring system are the relative humidity adjustment range (40–80 %), the temperature change range (20–80 °C), and the time to set the specified humidity level after replacing the valves (6–7 minutes). The electronic measuring system can be used for educational purposes, as well as for solving practical tasks related to the control and regulation of temperature and relative humidity of air in a closed space.