Luís Fernando Caparroz Duarte

In the current era of agricultural management practices, known as agricultural 5.0, optimal indoor environments are associated with comfortable temperatures, regulated humidity, and good air quality—essential variables to improve yields. Given this scenario, there is a need for innovative ecosystems that automate indoor environmental monitoring in an affordable and scalable way. This paper presents the scope of the development and validation of an IoT-based ecosystem designed to monitor and control environmental conditions in agricultural barns. The objective is to present a cost-effective and easily accessible environmental monitoring system for barn buildings and agricultural storage areas, promoting the welfare of animals, humans, and crops, and contributing to the sustainable development of the agricultural industry. The system integrates wireless sensors, predictive algorithms, a web interface and cloud infrastructure to optimize temperature and humidity. A proof-of-concept assessment was performed to determine whether the modular architecture offers scalability, while the responsive web interface ensures cross-device accessibility. The results show data accuracy above 95%, prediction efficiency of 96%, and increases in production yields. This solution demonstrates economic and operational advantages over existing technologies, promoting sustainability and automation in agricultural management practices in hangars and barns, in alignment with the United Nations’ Sustainable Development Goals (SDGs).

Anais do XIV Seminário de Extensão e Inovação & XXIX Seminário de Iniciação Científica e Tecnológica da UTFPR - SEI/SICITE (978-65-272-0788-7) - Sistema De Monitoramento De Borboleta Eletrônica Para Controle De Atuador Eletromecânico

Anais do XIV Seminário de Extensão e Inovação & XXIX Seminário de Iniciação Científica e Tecnológica da UTFPR - SEI/SICITE (978-65-272-0788-7) - Plataforma Robótica Experimental Para Auxílio No Manejo Agrícola

We present the design and fabrication of a reconfigurable smart-sensor for measuring moisture content (MC) and temperature in grains stored in silos, using a capacitance fringing field interdigitated sensor and using a resistance temperature detector (RTD), both implemented on a single conventional printed circuit board. The sensor was tested in laboratory, using corn kernels with percent MC in the range of MC $= 8\%$ to MC $= 32 \%$ and, using a simple relaxation oscillator and a frequency-to-voltage converter, we measured a capacitance variation of $\Delta C = 4.99$ pf, with a sensitivity $S = 0.21 \, \rm {pF}/\%$ MC. The RTD sensor, which uses the copper resistance of the PCB tracks, was characterized in the 10 $^\circ \text{C}$ – $50~^\circ \text{C}$ temperature range and the measured results presented a very linear behavior ( $R^{2} = 0.99888$ ) when compared to the measured temperature values using a commercial sensor (LM135). A modified bridge circuit was developed, where a linear behavior of the differential output was obtained. The developed configuration allowed for the independent adjustment of both the offset and the gain in the output voltage $V_{\text {out}}$ of the bridge. The bridge signal processing circuit was calibrated using an endpoint method, and the measured points between the calibration points presented a maximum endpoint nonlinearity error of $|E_{\text {nl}}| =\,\,0.64\,\,^\circ \text{C}$ .

Anais do XII Seminário de Extensão e Inovação & XXVII Seminário de Iniciação Científica e Tecnológica da UTFPR (978-85-5722-512-1) - Desenvolvimento De Sistema De Análise Do Tempo Atmosférico Para Aplicação Em Automação Residencial

Solar radiation and human activity generate ubiquitous temperature gradients that could be harvested by thermoelectric generators (TEGs). However, most of these temperature gradients are in the range of very few degrees and, while TEGs are able to harvest them, the resulting output voltages are extremely small (a few hundreds of mV), and DC–DC converters are necessary to boost them to usable levels. Impedance matching between TEGs and DC–DC converter plays a fundamental role in the energy harvesting efficiency. Therefore, it is essential to determine the output power of the system in different configurations, in order to decide on the optimum TEG connection. Here, we present an electronic circuit to measure the maximum power that can be harvested with low-voltage TEGs connected to a DC–DC converter. The developed circuit is an electronic controlled load that drains the maximum current from the output of the DC–DC converter while maintaining its output voltage at the maximum allowed value. Using a mechanical set-up able to apply precise low temperature gradients between the hot and cold side of the TEGs, experimental data using different configurations of TEGs are obtained. The measured results show that, for ultra-low voltages, the TEG ensemble’s output impedance plays an important role not only in the amount of the energy scavenged, but also in the onset temperature of the energy harvesting.

We present a capacitive smart sensor based on printed circuit board (PCB) technology to measure the amount of water content in a paper pulp at the wet end of a paper machine. The developed sensor incorporates in the same PCB the signal processing circuits. It is a handheld portable device, and its output is sent to the reading equipment using a Bluetooth wireless connection, providing to the sensor’s operator ease of mobility around the wet end of a paper machine. The prototype was tested in a laboratory, using a wire mesh to emulate the end of a paper machine, and we were able to measure and easily detect when it reaches the water content in the range of 90% to 92%, as required in the paper fabrication process. Standard deviation of the capacitance measurements at various moisture levels is four orders of magnitude smaller than the mean. The smart sensor was tested in the 20°C to 40°C temperature range, in a paper pulp with a gravimetric water content of 91%. Since the variation of capacitance with temperature is practically linear, we propose a simple linear compensation equation to correct the observed sensitivity with the temperature. To keep the signal processing circuits small, low cost, simple, and robust, a novel direct interface sensor to microcontroller circuit technique was used to make the capacitive measurement, allowing for measuring small capacitance deviations without high-frequency oscillators. It was shown that it is possible to integrate the signal processing circuits in the top layer of the PCB interdigitated sensor without adding noise or degrading the performance of the capacitive sensor.

Heat dissipation sensors operate based on the temperature dependence of the transient heat conduction within the soil, which is a function of the soil characteristics and its water content. After a heat pulse with controlled energy is applied to a heater, it is possible to show that the maximum temperature rise Δ TM measured in the temperature sensing element can be related to the volumetric water content of the soil θv [m³ , m⁻³]. The design and fabrication of a low-cost soil moisture multiprobe heat pulse sensor system using conventional printed circuit boards and surface-mount devices is presented. The proposed sensor is free of the needles' deflection problem present in conventional multiprobe sensors and is manufactured using conventional off-the-shelf electronic components. A precision low-power electronic signal conditioning circuit, using an instrumentation switched-capacitor building block, was developed and successfully used in the prototype. Due to an energy-efficient topology for the sensor and a low-power signal conditioning circuit, the average current consumption of the system (with one measurement per day) is only 3 μA. To demonstrate the feasibility of the concept, a prototype of the sensor was tested in soils with volumetric humidity in the range from θv = 0.05 m³ , m⁻³ to θv = 0.41 m³ , m⁻³ and, with a very low heating energy pulse (3 J), showed a sensitivity, normalized by the total energy applied, Γ = 211 x 10⁻³ °C , m³ , m⁻³ , J⁻¹. Compared with a button heat pulse probe sensor which has Γ = 192 x 10⁻³ °C , m³ , m⁻³ , J⁻¹, the developed sensor shows a higher normalized sensitivity.