Solar Powered Smart Irrigation Monitoring System Using IoT

Abstract

Water and food are the basic necessities of human being to survive life. Along with several environmental concerns and climate change, water scarcity and food security are growing concern in today’s society. Water irrigation remains the biggest water usage globally and creates a lot of water wastage. With the advancement of technologies nowadays, several strategies are developed in order to minimize the negative impacts on the environment. Using renewable resources and IoT technology, it can generate a sustainable and responsible conservation system over time.

The Solar-Powered Smart Irrigation System aims to provide an IoT solution in automating the watering process using an Arduino-based microcontroller and sensors. It is an energy efficient and eco-friendly system that generates electricity from the photovoltaic cells to supply water to the plants from the water pumps. The watering process is driven by the moisture content of the soil using sensors. Threshold limit are set for soil moisture sensor to ensure efficient and effective use of water resource. The main microcontroller unit controls the system whenever the sensor is across threshold value. Also, the system has built-in temperature and humidity sensors to monitor the climate condition on the specific environment. Another sensor is implemented to measure the water tank level which serves as storage capacity that supplies the water to the system. With the integration of IoT, automated irrigation can be easily access and remotely monitored over the mobile application through a wireless communication device. With these smart irrigation techniques, it replaces the traditional irrigation system that helps decrease the manual intervention and mistakes.

Introduction

Over the years, several development and innovation have come across to further minimize the rapid depleting of natural resources in the environment. Basic necessities such as food and water have an integral part of everyday lives on Earth. Water plays a significant role in the environment. Globally, 70% of water come from natural resources such as groundwater systems, lakes and rivers to support crop irrigations and feeding of livestock. With the irrigation systems, it is important to maximize plant productivity, efficient energy consumption and reduce water wastage. Several approaches have been done by the researchers on how to improve the irrigation systems.  With the global energy crisis, initiative for moving towards application of renewable resources carried out as possible solution. Investing on zero-carbon emission and using energy efficient products.

Figure 1: Global Water Usage 

The most abundant source of energy is the sun. Generating electricity from the solar energy through photovoltaic cells is being widely used nowadays. Encouraging the use of this energy-efficient system in various sectors creates a slowly declining cost to build-up the solar technology. This application can be used in irrigation system since it is a way producing clean energy for the environment. There are many applications of the solar generation system to consider such as irrigation system, livestock watering and domestic uses. (Hans Hartung, 2018)

Figure 2: Potentials and Challenges of Solar Generation

In New Zealand, there are various methods of application for an irrigation system including agricultural production. New Zealand has abundant water resources, however, to meet the present growing demand usage of water supply, it important to have a strategic and well managed irrigation practices. (Irrigation New Zealand, 2018) As irrigation system is essential for maximizing plant growth and high-quality crop production, it is essential to have an effective irrigation management. With the traditional irrigation system, water wastage and manual labour task is an issue.

Figure 3: Irrigation in New Zealand

Utilizing IoT technology on this era of evolving technology is a comprehensive approach in different types of applications including the irrigation methods. So, what is IoT? In a broad sense, IoT is simply an interconnection of devices through the Internet. These devices range from sensors to smartphones which is easily accessible when connected to each other. It can gather information that a user can generate and analyse data to create a solution. With IoT technology, it provides an opportunity to be more efficient in approaching things, saving energy and effort for being responsive in the interaction of devices. (Burgess, 2018)

Figure 4: Internet of Things

 With the approach of IoT in the smart irrigation system, it will be optimized for water resources and plant production. Also, the user can remotely monitor the system without being physical present in that particular area. The core IoT presents a collection and processing of data through the Internet and can quickly give immediate action for emerging issues and change in the conditions.  Smart Farming for IoT driven agricultural system evolves as Third Green Revolution which draws upon the applications of data driven analysis on based on technologies such as precise and accurate network for sensors and other devices. The integration of IoT creates a resource-efficient approach that delivers more productive and sustainable overall production efficiency. (Sciforce, 2019)

Background of the Project/Related Works

Several aspects have been research to provide solution for modern plant production. In this modern society, the paramount importance of environmental change is into people’s perspective especially with the energy and food demand with the increasing population rate. With the use of renewable resources, like the solar energy, it can be beneficial and increasingly popular method for irrigation use. Producing energy through sunlight can be easily access whenever the sun shines and feed the overall irrigation system. (Roblin, 2016)

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Most developed traditional system has been expensive and generates huge water loss. Example is the usage of diesel or gasoline engine motors for water pumps that are costly and high maintenance. The system also uses conventional energy use that often times become unreliable energy service.

In this project, we utilized the solar generation of electricity to supply the water pumps for the watering process. In this solar-powered system, the source of energy is free and is a cost-effective investment for the user. (Hans Hartung, 2018) The irrigation method to be used the drip irrigation which is a known efficient method of uniform distribution of water to plants. Drip irrigation has an efficiency of about 90% other than the sprinkler system which only has 75%-85%. The method is easy to install, inexpensive and maximizing plant growth due to reduce moisture levels. (McFadden, 2017) With drip irrigation system, it allows to control the amount of water the plants receive and uses drip emitters for close proximity. The system allows reduce water loss and usage and prevents soil drift and surface run off. Drift and surface run off are a phenomenon that water being blown into non-required area.

Several approaches have been created in monitoring data for the irrigations system such as using GPRS module and GSM based system. In an automated irrigation system using the GPRS module, the irrigation takes place using wireless sensor units to transmit data linked in radio transceiver. ZigBee technology is utilized for remote monitoring of data that can be access through a web server via mobile network. Due to the ZigBee protocol, the system may become costly and complex system approach. (Pravina B. Chikankar, 2015)

In an automated irrigation system using GSM approach, the implementation of monitoring and controlling is based on GSM module. GSM (Global System for Mobile Communication) is a standard use for wireless communication with embedded design and enhance application for monitoring and controlling system. The interface between the user and the system is through SMS on GSM network. (Saurabh Suman, 2017)

This project will implement an IoT technology based on remote monitoring app called RemoteXY. The information from the sensors is then sent to a mobile application graphical interface through a wireless communication device. Armed with the wireless-enabled connection, the user can intelligently monitor the conditions eliminating the need for manual intervention.

Objectives

1. To design and implement a Solar-Powered Smart Irrigation System using IoT Approach
2. To build an energy-efficient and cost-effective system using renewable resources
3. To integrate the system using various sensor parameters such as temperature and humidity sensor, soil moisture sensors and tank storage capacity sensor to collect information
4. To monitor and track the system using IoT technology

Scope of the Project

  This project about the design and fabrication of Solar-Powered Smart Irrigation System will be implemented in New Zealand. Integration of various sensors such as soil moisture sensor, proximity sensor and microcontroller is established to create performance and efficiency. The development of the project mainly focused on providing solutions related to electrotechnology which consists of Arduino-based microcontroller and wireless communication device. Also, the paper is focused on using renewable resources and introduction of IoT solution. Other systems presented will be discussed on different papers.

Work Breakdown Structure

 As illustrated on Figure 24, it shows the work breakdown structure for the development of the Solar-Powered Smart Irrigation System. It consists of seven main phases and it’s sub-activities.

Figure 24: Work Breakdown Structure

Project Methodology and Requirements

Working Principle

The developmental concept of solar powered smart irrigation system is to automate the irrigation process in an agricultural area. This is to minimize the carbon footprint in which the project aims to provide an energy efficient and plant productivity process. The “Solar Powered Smart Irrigation System” is a clean energy device that generates electricity from photovoltaic cells through solar technology. A back-up battery was also installed for excessive power storage and serves as a power back up in the event of minimal solar power.

Figure 5: How Solar Energy Works (Turner, 2012)

This is an Arduino-based microcontroller system in which it controls the overall system operationality and functionality. Sensors are utilized for transmitting real time data for monitoring process that include the climate conditions based on temperature and humidity sensor, the moisture content of the soil and water storage capacity. Sensor parameters are set to specific set point values to provide proper watering process in which the water pump is controlled by the microcontroller. For the remote monitoring and tracking purposes for the sensors, the system utilized a mobile application called Remote XY. RemoteXY is an easy mobile graphical interface that creates an interaction between the user and the system.

Figure 5: How RemoteXY Works

The aim of this project is to improve the overall efficiency and sustainability that utilizes clean-energy and technological innovation. With the revamp of IoT on agricultural business, it will create a strategic and well-managed irrigation practices. This may result to good environmental outcomes and overcome perceived climate intensification issues.

Figure 6 represents the block diagram of the essential components of the solar powered smart irrigation system.

Figure 6:  Block Diagram of the Smart Irrigation System

Based on Figure 7, it represents the flow chart of how the irrigation system works. It starts with the mobile app initialization of the user and powering on the main controller of the system. Various sensors will acquire data from the temperature and humidity sensor, moisture sensor and water tank level sensor. For the water pumps to work, set point values have been establish within threshold limits. The acquired data will be sent to the mobile application for the user to remotely monitor the system via the Wi-Fi module.

Figure 7: Flow Chart of the Irrigation System

Project Design Hardware Components

 The design of the solar powered smart irrigation system has the following components:

a)      Arduino Uno – the main controller of the unit that is an open source platform for any development environment. It is microcontroller board based on 8-bit ATmega328P microcontroller. It consists of 14 digital input/output pins, 6 analog input pins, USB connection, power jack and reset button. The system has also components that includes crystal oscillator, voltage regulator and serial communication. The Arduino Uno can be used to communicate in other devices using UART TTL (5V) on digital pin 0 (Rx) and digital pin (Tx). It can also communicate via USB drivers using ATmega16U2 firmware to be connected on the computer. The Arduino Uno can be programmed through an Arduino software using Wire library that can simply the use of I2C and SPI communication.

Figure 8: Arduino Uno Pinout Diagram

Figure 9: Arduino Uno Technical Specifications

b)      Solar Panel – Photovoltaic arrays generates electricity from solar energy. The 12V solar panel is in accordance with IEC61215:1993 standards, using low iron tempered glass and EVA film with TPT back sheet to encapsulated cells.

Figure 10. Solar Panel

c)       Solar Charge Controller – this compact solar controller uses Pulse Width Modulation (PWM) to manage battery charging from a connected solar panel. It features light and timer control, similar to street lights, and three charging states (bulk, equalise, and float charging). It provides all the important safety features such as overcharge, over-discharge, over-current, short-circuit, and reverse-polarity protection. (Jaycar Electronics, 2019)

Figure 11: Solar Charge Controller Specifications

d)      12V Battery – the main power supply of the system which is interconnected with solar charge controller and solar panel. If electricity is not generated to the solar panel as lack of sunlight, the supply power to the system comes from the battery. The solar panel can also charge the battery in the event of excessive power supply.

Figure 12: 12V DC Battery

e)      HC-SR04 Ultrasonic Distance Sensor -  it used as water tank storage level indicator for the irrigation system. It triggered to set within threshold limits that indicate when the tank level is at high or low. The sensor consists of two ultrasonic transducers which converts the electrical signal into ultrasonic sound pulses. It has an accuracy of 3mm and operates on 5V that can be connected on the microcontroller. (Last Minute Engineers, 2019)

Figure 13: HC-SR04 Ultrasonic Distance Sensor

Technical Specifications and Pinout Diagram

f)        Capacitive Soil Moisture Sensor – the capacitive soil moisture sensor measures and detects the soil moisture level through capacitive sensing if the plants need water. It is a corrosion resistant material compared to other moisture sensors. It operates on 3.3V~5V with high sensitivity and accuracy.

Figure 14: Circuit diagram of the Soil Moisture

g)       Relay Module – the system consists of two relays: 1) the 5V 4-channel relay interface board able to control the water pump for the plants. 2) the 5V 1-channel relay for the water tank. Both relays is controlled directly by microcontroller. (Surplustronics, 2018)

 Figure 15: Relay Module

h)      DHT11 Temperature and Humidity Sensor – It is an 8-bit microcontroller to output the values of temperature and humidity. The sensor has NTC (Negative Temperature Coefficient) to measure from 0°C to 50°C and humidity from 20% to 90% with an accuracy of ±1°C and ±1%. The sensor module is already embedded with resistor to interface with the microcontroller.

Figure 16: DHT11 Technical Specifications

and Pinout Diagram

i)        ESP8266 WiFi Module – this module is popular for its application on Internet of Things. The operating voltage for this module is 3.6V. It is a self-contained SOC that integrates with TCP/IP protocol that can communicate with the microcontroller to WiFi network. (Darshil, 2017) (Darshil, 2017)

Figure 17: ESP8266 Module Pinout Diagram

j)        Water Pump – the system consists of two pumps: 1) for the water storage tank 2) for the watering of plants in which the water takes from the storage tank and output it through the valves.

 Figure 18: Water Pump

k)       Solenoid Valve – each valve has input and output. The input takes the water from the storage tank, then allows water to the output valve once the microcontroller sense data from the soil moisture sensors. This operation allows uniform and controlled operation in irrigation system.

 Figure 19: Solenoid Valve

Project Design Software Applications

 For the smart irrigation system to be fully functional and operational the following applications are used:

a)      Arduino IDE Software – used to program the system. It is an open-source platform that is easy to write programming language and upload to the microcontroller. It can on any software environment like Windows, Mac OS and Linux.

 Figur Figure 19: Solenoid Valve e 19: Solenoid Valve

Figure 20: Arduino IDE Software

b)      Proteus – application used for circuit simulation of the overall system.

Figure 21: Proteus Software

c)       RemoteXY – mobile application with user graphical interface for IoT approach. This application serves as the remote monitoring of the system.

                Figure 22: RemoteXY Application

d)      EasyEDA – a free online circuit design software for schematic diagram and PCB Layout.

Figure 23: EasyEDA Application

Project Implementation

 The Arduino Uno is the main component of the solar powered smart irrigation system and is photovoltaic cells and battery that serves as the main power supply. Once the supply is connected, the microcontroller system will initialize all the connected device including the sensors, relays, the water pump and the wireless module. Once the parameters are collected from the temperature and humidity sensor, soil moisture sensor and the tank storage capacity level, the data is sent wirelessly and display on the mobile application interface. Based on Figure 7, it represents the flow chart of the system while on Figure 6 shows the block diagram of the diagram with its essential components.

 The system has a DHT11 sensor which measures the climate condition on the area such as the temperature and humidity.

 The procedure of the irrigation process is shown on Figure 24. Once the soil moisture content is determined by the soil moisture sensor, the controller will initiate the process in irrigating the plants. Threshold limit of 30%-55% represent the set moisture levels for the soil. If the read data is not within its range, such as the soil moisture content is read at 20%, the microcontroller with initiate to trigger the relays to activate the valves and switch ON the pump. In this way, the valves are open to water the plants since it indicates a low soil moisture content. The valves are switch ON until the desired moisture content is reached. When the moisture content is within the threshold limit, the microcontroller will signal to the relay to stop for the valves to switch OFF. The acquired data is displayed on the mobile application with indicators of the valves if it is on open or close state.

Figure 24: Soil Moisture Content Flow Diagram

The presented Figure 25 shows the flow diagram for the Water Storage Tank. The threshold limit for the tank is within 30% – 90%. Once the capacity of the storage tank is below the limit such as 10%, the sensor will trigger the microcontroller that it needs to be filled up by water. The water pump will take water from the source into the input valve and sends pressure to the output valve to fill the tank. The valve will be switch on by a relay. Reaching the maximum level at 90%, the relay will close the valve. Water supplied to the storage will be from river streams or ground water systems for efficient water use. The acquired data is displayed on the mobile application which is sent wirelessly and indicates if the valve is on open and close state.

Figure 25: Water Tank Level Capacity Flow Diagram

Schematic Diagram

 The schematic diagram shows the necessary connections and components to implement the solar powered smart irrigation system.

 The system generates electricity from the photovoltaic cells through solar energy that regulated by the solar charge controller. The battery is connected to the solar charge controller which allows the battery to be charge by the solar panel. The 12V DC battery supplies the power for the motor pumps for storage tank and to water the plants. The main microcontroller which is the Arduino Uno is connected to the temperature and humidity sensor, relays, soil moisture sensor and the ultrasonic sensor to measure the tank level. Soil moisture sensors are connected to the analogue pins of the Arduino while other connections are in digital pins. For the Ultrasonic sensor connection to Arduino, the Trigger (pin 9) and Echo (pin 10). The DHT11 sensor is connected to pin 2 for that can be used for analog and digital read. The components such as the sensors are connected to the 5V power of the microcontroller while the relays are connected directly to the 12V power supply. For the ESP8266 WiFi Module, it is connected to a 3.3V supply on the microcontroller since it only operates within that voltage to establish better communication with the Arduino and other devices. The monitoring of the data is sent wirelessly to the mobile application through the ESP8266 WiFi Module. The WiFi module connection on the Arduino is Tx (pin 0) and Rx (pin 1). Relay are connected on digital pins 11, 12, 13, and the water pump for storage tank is connected at pin 8 on the Arduino microcontroller.

Figure 26. Schematic Diagram

Results and Discussion

 After several attempts and encounter different challenges to build the circuit and prototype, the Solar Powered Smart Irrigation System was successfully built and fully operational. Figure 27 shows the final prototype of the project. Outside the prototype, it displays the WiFi module. Through this wireless communication device, it communicates with the Arduino microcontroller and the Mobile application RemoteXY. This device is responsible for the monitoring of data from the sensors.

The components installed are in good working condition and meet the desired requirements of the system. Another module displayed is the Solar Charge controller. Also, the DHT11 sensor which measures the temperature and humidity where the prototype is placed in an area.

Figure 27: Final Prototype of the Project

Figure 28 below shows all the components of the system including the main board, pump, water hose, relays and valves.

Figure 28: Components of the System

Figure 29 represents the water tank storage for the irrigation system. The ultrasonic sensor is put on the top part of the container for more stabilization and to avoid contact with water.

Figure 29: Water tank storage prototype

Figure 30 represents the main page of the mobile application graphical user interface. The software is available for both Google play for Android devices and App Store for iOS devices. The interface displays three main pages consists of Main, Moisture Level and Water Level. The main page displays the temperature and humidity sensor values.

 Figure 30: RemoteXY Mobile Application

Analysis of System Data

 The figure shows the water level sensor which indicates the reading at 93%. The red indicator represents that the water pump is OFF since it reaches the desired level set at the microcontroller. The maximum value is set to 90% hence, it is in close state and stopped filling the tank.

 Figure 31: Water Level Pump OFF

 The figure below represents the reading of water level sensor at 23%. The green indicator represents the pump is ON state which enables the microcontroller to open the pump and fill the tank with water. Once the tank reaches the desired level of capacity, the controller will stop the pump by sending proper signal to the relays.

 Figure 32: Water Level Pump OFF

 The figure below represents the three states of the soil moisture sensor. The desired limit for the moisture sensor is between 30-55% that indicates the moisture level is normal. Below 30%, the sensor indicates that the moisture level is low which means it needs to water the plants. Above 55%, moisture level state is high which does not need watering of plants.  At Figure 33, it indicates that the sensor 1 is at 44% which shows that the moisture content is within the desired level, hence the pump is on CLOSE state. While sensors 2 and 3 indicates 0% that is below the limit, which turning ON the pump to start the watering process.

Figure 33: Soil Moisture Sensor 1

Figure 34: Soil Moisture Sensor 2

Figure 35: Soil Moisture Sensor 3

The figure represents the moisture sensor at 0% state which may indicate a severe dryness of soil content that causes the weather conditions in an area. In this state, the pumps are all turned ON until it reaches the desired level. Checking of the circuit and soil should be done manually at this time in cases of defective or short-circuited components.

 Figure 36: Soil Moisture Sensor are Turned ON

 The figure represents that the sensor reading is exceeds the maximum level of 100%. This may indicate that the sensors maybe submerged on water due to heavy rainfall and causes the plants to be flooded with water. During rainy season, the solar panel does not generate solar energy due to lack of sunlight. The system will only depend on the battery that last within 15 hrs. On this time, the watering of plants are not needed since the rainfall can give adequate amount of water to plants.

Figure 36: Soil Moisture Sensor are Turned OFF

Challenges in the Implementation

Implementing the hardware and software components of the solar powered irrigation system is quite a challenge. It requires ample time and effort to dedicate on the working principle of the project from the research and design phase to the implementation of the project. It needs a better understanding for carefully check the datasheets and technical specifications of the components, along with compatibility issues. Here is the list of the challenges we encountered for the entire project:

1)      Some of the components are not readily available in New Zealand that opted to outsource the materials to other countries like China and US.

2)      Shipment delays are encountered and costly Airfreights thus delaying the project prototype.

3)      Even if the components are carefully checked, there is an instance that the components are short-circuited hence resulting to burnt boards and components and makes the situation complicated and start-over with the project.

4)      During the breadboard implementation to test the circuit, some components are loosely connected finding it difficult to troubleshoot the issue with all the components connected.

5)      The pinout of the soil moisture sensor leads to different connections that results to sensor misread the values to no output reading.

6)      The microcontroller and the relay have different power supply to avoid voltage regulation issue between the components

7)      Implementation of the Arduino IDE software for programming the circuit such as defiing variable and correct usage of components library for proper communication with the Arduino microcontroller.

8)      Lastly, during the testing of the components on the final prototype, it does not function well and needs further troubleshooting.

Limitations of the Project

 The solar powered irrigation system has the following limitations:

1)      The system utilizes two power supply that is connected with the solar panel, 9V for microcontroller and connected components such as sensors, and 12V for water pumps.

2)      The distance of the WiFi connection is short range (20m)

3)      The mobile application RemoteXY represents a graphical interface for monitoring purposes only

Conclusion and Recommendation

 The solar powered smart irrigation system using IoT demonstrates a collection of data using sensors for productivity and efficiency. The generates a clean energy by utilizing the solar generation technology which improves cost management and waste reduction for overall improved system performance. The system also allows monitoring the irrigation process without manual intervention hence achieving optimized results and more efficient use of water resources. The system is set to deliver a more productive and sustainable irrigation method and beneficial to the environment.

 The system may be further modified in the emerging technology which stores the data to the cloud server for further analysis and immediate actions if necessary. Also, several sensors can be added to the system such as tracking the climate conditions with rainfall sensor and further improvement on the large-scale basis.

Works Cited

• Burgess, M. (2018, February 16). What is the Internet of Things? WIRED explains. Retrieved from WIRED: https://www.wired.co.uk/article/internet-of-things-what-is-explained-iot
• Darshil, P. (2017, August 31). Things You Should Know Before Using ESP8266 WiFi Module. Retrieved from Hackster IO: https://www.hackster.io/PatelDarshil/things-you-should-know-before-using-esp8266-wifi-module-784001
• Hans Hartung, L. P. (2018). The benefits and risks of solar-powered irrigation – a global overview. Food and Agriculture Organization of the United Nations, 51. Retrieved from Food and Agriculture Organization of the United Nations.
• Hansen, J. (2019). Advantages & Disadvantages of Irrigation Systems. Retrieved from Hunker – Gardening Basics: https://www.hunker.com/13404714/advantages-disadvantages-of-irrigation-systems
• Irrigation New Zealand. (2018, August 29). Irrigation New Zealand: Good Farming Practices and Fast Facts. Retrieved from Irrigation New Zealand: https://www.irrigationnz.co.nz/KnowledgeResources/Category?Action=View&Category_id=75
• Jaycar Electronics. (2019). Miniature 12V 3A PWM Solar Charge Controller. Retrieved from Jaycar Electronics: https://www.jaycar.co.nz/miniature-12v-3a-pwm-solar-charge-controller/p/MP3762
• Last Minute Engineers. (2019). How HC-SR04 Ultrasonic Sensor Works & Interface It With Arduino. Retrieved from Last Minute Engineers: https://lastminuteengineers.com/arduino-sr04-ultrasonic-sensor-tutorial/
• McFadden, C. (2017, May 06). How Exactly Does Drip Irrigation Work? Retrieved from Interesting Engineering: https://interestingengineering.com/how-exactly-does-drip-irrigation-work
• Pravina B. Chikankar, D. M. (2015). An automatic irrigation system using ZigBee in wireless sensor network. 10.1109/PERVASIVE.2015.7086997, 1-5.
• Roblin, S. (2016, August 3). Solar-powered irrigation: A solution to water management in agriculture? Retrieved from Renewable Energy Focus: http://www.renewableenergyfocus.com/view/44586/solar-powered-irrigation-a-solution-to-water-management-in-agriculture/
• Saurabh Suman, S. K. (2017). Solar Powered Automatic Irrigation System on Sensing Moisture Content Using Arduino and GSM. International Journal of Advanced Research in Electronics and Communication Engineering (IJARECE), 549-555.
• Sciforce. (2019, February 12). Smart Farming: The Future of Agriculture. Retrieved from iOT For All: https://www.iotforall.com/smart-farming-future-of-agriculture/
• Surplustronics. (2018). 4-Channel 5V Relay Module Coupling Optocoupler. Retrieved from Surplustronics: https://www.surplustronics.co.nz/products/7592-4-channel-5v-relay-module-coupling-optocoupler
• Turner, S. (2012, October 17). How Does Solar Energy Work? Retrieved from SOLAR ENERGY BASE. Staring at the sun.: https://www.solarenergybase.com/how-does-solar-energy-work/

Appendixes

Arduino IDE Software Code

Bill of Materials

Assembling the components and making the prototype