## 4 Progress of Data Processing Modules for Solar PV Monitoring System
### Arduino Based Module  
The Ivrea Interaction Design Institute invented Arduino technology which was intended for students with no background in the field of electronics hardware as well as programming [49]. Due to the easy availability of hardware design and software programming codes, Arduino is currently one of the most influential open-source hardwares to work with. Arduino IDE is used to program an Arduino board which is a simplified  
Figure 6: BeagleBone-based monitoring of solar PV systems. version for C++. Furthermore, Arduino boards can read input from several sources as well as publish the output in various forms such as the switching on/off of the motor, writing a text online, and controlling light [50]. [PERSON] et al. [34] designed a monitoring system for standalone PV systems by utilizing low-cost Supervisory Control And Data Acquisition (SCADA) with Arduino Uno. The data was extracted by the current sensor ACS712 and a voltage sensor and sent to the Arduino Uno microcontroller which was further transmitted to the computer through a USB cable. Furthermore, the Modbus library was installed on Arduino to set up the communication between Arduino and SCADA. The main aim of the proposed system was to determine the MPPT efficiency of the system from the data extracted by the sensors. In addition to the proposed system, more functionality in terms of observing electrical as well as environmental parameters such as panel voltage, panel current, temperature, and humidity could be implemented for future research works. Furthermore, [PERSON] et al. [51] developed a low-cost data logger system for monitoring remote PV systems through Arduino Uno. The proposed design meets the necessary requirements laid down by the International Electro-Technical Commission (IEC). The low-cost data logger utilizing Arduino was capable of operating in remote locations with less network coverage and with minimum maintenance costs. To overcome the limitations of Arduino Uno, the author suggested improvements such as integrating the 12C bus with PCB, a Real-Time Clock (RTC), two external ADCs, SD flash memory, a visual interface, and a power consumption module to make the system compatible according to IEC standards. The temperature sensor DS18B20 along with the current sensor and voltage sensor were placed to extract the data and to send it to an improved data logger. The algorithm to operate Arduino was written in C/C++ with Arduino IDE. The test on the improved data logger was held for one month to test the efficiency in compliance with IEC standards. For further upgradation, the suggested model could be developed for a large coverage area with more data handling capabilities, and the complexity of the model could be reduced by using an easy programming language. Recently, [PERSON] et al. [52] presented an Arduino-based performance monitoring system for floating solar PV systems. In this approach, the main controller was regarded as Arduino Nano. Furthermore, electrical parameters such as voltage, current, and output power of solar PV modules of 10 W were monitored. Moreover, the monitoring of the module was performed on both the floating system as well as a land system. It was concluded that power output and efficiency were higher in the floating system compared to the land system. The presented system is simpler in implementation; hence, the system can be developed with high wattage monitoring capabilities. [PERSON] and [PERSON] [53] introduced a hybrid approach with PLC and Arduino to monitor the temperature of solar panels in Smart Grids/Micro-Grids applications. The acquisition and display of data were performed in combination with PLC and SCADA while the extraction and transmission of data were completed by the Arduino MEGA 2560 R3 platform. Although the extensive extraction of temperature was executed, the utilization of various other sensors for the extraction of electrical and environmental parameters could be considered in future works.