Internet of things based smart photovoltaic panel monitoring system

ABSTRACT


INTRODUCTION
Electricity is a part of life for everyone in the present day.To meet their energy needs, developed countries have already adopted renewable energy resources and smart technology [1], [2].Recently, sunlight is now recognised as the most popular renewable energy source, filling the difference between electricity production and consumption as shown by Eisapour et al. [3].Because of advancements in solar panel technology and cost reductions, solar panels have advanced in power generation.The device continually monitors the photovoltaic (PV) panel and transmits the output by using the internet using an internet of things (IoT) network.The primary goal of solar panel monitoring system is to maintain the optimum power output as mentioned earlier [4].By monitoring the maximum output power of the solar power station to spot faulty connections and dust or pollutants deposited on the PV panels, these contaminants have an impact on the PV panels' performance [5].
Monitoring the system using human efforts takes more time and is considered a difficult task.As a result, sensing components and their peripheral units helps to simplify the monitoring process as mentioned earlier [6].Most likely, the sensors are modest in size and operate in any climatic situation with minimal power needs.The IoT is a system that runs without a large portion of wire connections for system monitoring as shown by Keerthana et al. [7].The flowchart of the suggested method for integrating the system is displayed in Figure 1.Moreover, the IoT can measure readings via wireless connections using Bluetooth and Wi-Fi modules.Because of their ease of installation, cost-effectiveness, and space constraints, the IoT is attempting to adapt itself to a variety of applications [8], [9].While monitoring the PV panels, poor connections and dust accumulate on the panels, resulting in decreased output and other difficulties affecting the functioning of the solar panels.

PROPOSED SYSTEM
A fundamental goal of the proposed work is to monitor the temperature, humidity, voltage, and solar irradiation of the PV panel.PV panels are now used in a variety of fields to generate electricity as shown by Rani et al. [11].Solar radiation falling on the panel diminishes as the humidity in the solar panel rises and the output voltage falls as well.As a result, high humidity reduces ideal power.The solar panel is linked to a microcontroller called NodeMCU ESP8266.The block diagram of the suggested method for integrating the system is displayed in Figure 2. 343 the DHT11 sensor is referred to as a digital humidity and temperature sensor as mentioned earlier [12].PV panel is linked with a GY-302 BH1750 digital light intensity module, the irradiance of the solar panel is observed.The irradiation unit of measurement is used to describe radiation that is falling on the surface.The circuit design of the suggested method for integrating the system is displayed in Figure 3.With the Wi-Fi module, an interface is shared between the controller and the cloud server, and subsequently, the panel's parameters, such as voltage, temperature, humidity and solar irradiation, are sent to the server.The panel's parameters are recorded on the server every hour and day, allowing for scrutiny and comparison [13].Data from various solar panels is combined via an IoT platform, which applies analytics to communicate the most crucial data with applications created to satisfy particular requirements.The schematic design of the suggested method for integrating the system is displayed in Figure 4.

HARDWARE USED FOR IMPLEMENTATION 3.1. Voltage sensor
A voltage sensor is a device that detects changes in external stimuli and reacts to the system's output in the form of voltage.There are numerous voltage sensor ranges, in which authors uses sensor ranges of 0-25 [14].It is used to monitor the direct current (DC) or alternating current (AC) voltage of a solar panel.The voltage sensor is designed simply, yet it may be utilised in a variety of applications.It has two resistors with resistance values of 30 KΩ and 7.5 KΩ. Figure 5 illustrates the voltage sensor that was utilising in this setup.The voltage sensor is works on the principle of "voltage divider" as (1): where,   : O/P voltage (V),   : I/P voltage (V),  1 : first resistor's resistance (Ω),  2 : second resistor's resistance (Ω)/

DHT11 sensor
The DHT11 sensor is a low-cost sensor that is used to monitor the humidity and temperature of a solar panel system.The DHT11 sensor has a temperatures ranging from 0 °C to 50 °C, and humidity levels ranging from 20% to 90%.Temperature precision is + or -1°, while humidity accuracy is + or -1%.This sensor is easily connected to the NodeMCU ESP8266 microcontroller device.To measure temperature, DHT11 has negative temperature coefficient (NTC).It means that when resistance decreases, temperature rises.The resistance between the electrodes is measured by the DHT11 sensor to compute relative humidity for more details [15].Figure 6 illustrates the DHT11 sensor that was utilising in this setup.The DHT11 sensor translates resistance measurements to relative humidity and transmits humidity and temperature information to the NodeMCU ESP8266 microcontroller device.
where,   : relative humidity,  2 : vapour pressure of water molecule,   : vapour saturation pressure of water.

GY-302 BH1750 sensor
A GY-302 BH1750 sensor is used to measure light intensity, also known as solar irradiation, which is the quantity of light received from the region of the PV panel [16], [17]: − Solar constant: amount of radiation reaches the earth surface.− Solar zenith angle: the angle formed between the sun's beam and a line perpendicular to the surface of the earth.
The GY-302 sensor has a 3 to 5 DC voltage operating range and a 16-bit analogue to digital (A/D) converter built in.The I2C bus interface is appropriate for receiving ambient light.The analogue and digital signals from the GY-302 sensor module will be received and shown on the Arduino IDE's serial monitor.Figure 7 illustrates the GY-302 BH1750 sensor that was utilising in this setup.

NODEMCU ESP8266
Node micro controller unit (NodeMCU) is a free and open IoT platform's low-cost microcontroller.The ESP8266 system on chip (SoC) Wi-Fi module powers the NodeMCU.It connects to the object and sends data via the Wi-Fi protocol [18], [19].Figure 8 illustrates the WI-FI Module-ESP8266 that was utilising in this setup.
It is the most cost-effective and accessible IoT platform since it is open source.As compared to the Arduino UNO, the NodeMCU ESP8266 microprocessor consumes extremely low power as shown by Cheragee et al. [20].To programme the NodeMCU, the Arduino IDE is typically used.Because of its small size and built-in Wi-Fi module, this device is mostly utilised for IoT-based applications [21].

Photovoltaic panel
A solar panel is a device that transform the energy of light (solar rays) into electrical energy.The maximum power (Pmax) is 3 watts, and the nominal voltage is 6 DC volts.A solar panel with a voltage at maximum power of (Vmp) 7.5 volts is to be employed.Figure 9 illustrates the PV panel that was utilising in this setup.For the suggested technique, a polycrystalline solar panel is required [19].The optimal output power, depending on the availability of sunlight, is 3 watts per day.An ultraviolet (UV) and scratch resistant coating are applied to the solar panel.It is a 9×2-cell array built of polycrystalline silicon material [22], [23].

. Arduino (IDE)
The Arduino (IDE) software application has a "text editor for writing code" section where we may input the necessary code.The C programming language is used in the proposed model.Then comes the "message area," in which if the code is possibly wrong, it will be displayed.The Arduino software is compatible with all Arduino boards, including the Arduino Uno, Arduino Nano, and NodeMCU ESP8266.This software simplifies the process of writing code and uploading it to the Arduino board [24].The "toolbar with buttons" provides a variety of features such as run, upload, download, and debugging the code.The Arduino IDE software is connected to the microcontroller board and simply feeds the code to it.It is simple to download and install.Install any required drivers, then connect the microcontroller board to your computer through USB.Simply chose the used board, then the serial port, and finally upload the application.

Blynk application
Blynk is a software application for the IoT platform.Blynk server is an open-source network that is in responsible for sharing data from the NodeMCU ESP8266 microcontroller board to the Blynk mobile application [25].Blynk is simple to use; simply run the Arduino IDE software and import the Blynk libraries.Next, choose the template ID and device name before uploading the program to the microcontroller board [26].Overall, Blynk is the best software since IoT models may be launched for free at any time.The subsequent Figure 10 shows the before and after connecting to the microcontroller.The proposed system (Blynk) is connected to a microcontroller board and the Arduino IDE software, letting us to monitor voltage, temperature, humidity, and solar irradiation data from PV panels [27].

RESULTS AND DISCUSSION
The project's outcome is exhibited utilising the Blynk IoT platform.The following results were achieved by integrating several sensors on the Blynk mobile application.Every one-minute, the values of the DHT11 sensor, voltage sensor, and GY-302 BH1750 sensors are updated.Begins at 7:30 AM. and ends at 4:30 PM, the authors gathered data for nine hours.To get the information acquired on November 26, 2022 by Table 1 [28].The super chart of the proposed structure and data stream of the Blynk application is displayed in Figure 11.Remotely monitored solar panel characteristics include voltage, temperature, humidity, and irradiance.

CONCLUSION
In this work, researchers successfully established an IoT-based PV panel monitoring system, which gives significant insights into environmental conditions and PV panel performance.The IoT-based PV panel monitoring system was created by methodically integrating a network of sensors capable of recording realtime data on the surrounding environment and PV panel functionality.One of the the system's most distinguishing characteristics was its intuitive design, which was available via online dashboard and apps for mobile devices.However, the study is constrained to a limited time frame and sensor set, which limits its generalizability.Future research should look at long-term data trends, increase sensor variety, and apply predictive analytics to improve real-time monitoring and maintenance of solar panel systems.

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ISSN: 2089-4864Int J Reconfigurable & Embedded Syst, Vol. 13, No. 2, July 2024: 341-351 342 However still, hardly a backup data is available to the current researchers.Consequently, this work provides a simple and reasonable IoT-based system for monitoring PV panel parameters, with an extra backup data preserved on a cloud storage system.The IoT-based solar panel monitoring system collects data from sensors such as the voltage sensor, digital humidity and temperature (DHT11) sensor, and GY-302 sensor and stores it in the cloud-based application to monitor PV panel parameters such as voltage, temperature, humidity, and solar irradiation[10].

Figure 2 .
Figure 2. Block diagram of the proposed structure

Figure 3 .
Figure 3. Circuit diagram of proposed structure

Figure 4 .
Figure 4. Schematic diagram of proposed structure

Figure 5 .
Figure 5. Top view of voltage sensor Figure 6.Top view of DHT11 sensor Internet of things based smart photovoltaic panel monitoring system (Arcot Ramakrishnan Kalaiarasi)345( ℎ ) ×

Figure 10 .
Figure 10.The before and after connecting to the microcontroller

347Figure 11 .
Figure 11.Super chart of the proposed structure and data stream of the Blynk application

Figure 12 .
Figure 12.Solar panel output temperature gauge and graph obtained using Blynk application

Figure 13 .
Figure 13.Solar panel output voltage gauge and graph obtained using Blynk application

Figure 15 .
Figure 15.Solar panel output irradiation gauge and graph obtained using Blynk application