In this project, Arduino and ESP32 will be used to learn about IoT-based soil nutrient monitoring and analysis systems. Agriculture relies heavily on healthy soil. The nutrients that are provided by the soil contribute to the

overall growth of a crop. A crop's production is highly influenced by a number of the soil's chemical and physical features, including its moisture level, temperature, and the proportions of nitrogen, phosphorus, and potassium present in the soil. The open-source hardware has the capability of sensing these features, and this information may then be applied in the field. A system for the monitoring and analysis of soil nutrients, such as nitrogen, phosphorus, and potassium, is one of the things that is going to be worked on as part of this project. The farmer will be able to use this system to monitor the temperature and moisture of the soil as well as the nutrient content of the soil. All of these parameters can be monitored wirelessly on the farmer's mobile phone or on the computer system. We are going to employ a capacitive soil moisture sensor in order to get an accurate reading of the soil's moisture content. Using the DS18B20 Waterproof Temperature Sensor, one is able to get an accurate reading of the temperature of the ground. In a similar vein, we will make use of a Soil NPK Sensor in order to determine the NPK values of the soil. The Arduino board is compatible with all of these sensors, making it simple to interface with them. We are going to monitor the data using the graphical and numerical formats provided by the Thingspeak Server. In order to transfer the data to the server, we need to be connected to a GSM or WiFi network in the field. The agricultural industry, on the other hand, does not have access to these networks. In order to find a solution to this problem, we will be utilizing the NRF2401 Wireless transceiver Module to transmit the data from the sensor Node to the Gateway.

It is possible for the data sent by the transmitter to be wirelessly relayed to the receiver from a distance of one kilometer. The ESP32 WiFi Module, which has access to the WiFi Network, is used in the construction of the receiver. The data can be sent to the Thingspeak Server if the user connects their device to this WiFi Network. Therefore, let's create an Internet of Things-based system for analyzing, monitoring, and testing the nutrient content of soil using nothing more than a wireless sensor network, Arduino, and ESP32.

Arduino Board - Arduino Nano ESP32 Board ESP32 ESP-32S Development Board NR24L01 Module NRF24L01 PA+LNA 2.4gHz - Wireless Transceiver Module NPK Sensor - JXIOT Soil NPK Sensor Soil Moisture Sensor - Capacitive Soil Moisture Sensor v2.0 Temperature Sensor - DS18B20 Waterproof Temperature Sensor Modbus Module - MAX485 Modbus

Resistor 4.7K Resistor Power Supply - 9V - 12V DC Supply Connecting Wires Breadboard Sensors Used: Soil Moisture, Temperature & NPK The IoT-based soil Nutrient Monitoring, Analysis, and Testing project calls for a few sensors, which will be discussed in further depth in the following paragraphs. Capacitive Soil Moisture Sensor We need a Soil Moisture Sensor in order to measure the amount of moisture in the soil. It has been determined that a capacitive variety of soil moisture sensor is the most suitable for this purpose. We will be using an analogous capacitive soil moisture sensor that utilizes capacitive sensing in order to determine the amounts of soil moisture. What this indicates is that the capacitance shifts depending on the amount of water that is present in the soil. The capacitance that was measured was transformed into a voltage level that ranged from a minimum of 1.2V to a maximum of 3.0V. Because they are constructed out of a material that is resistant to corrosion, capacitive soil moisture sensors have a long service life. This is one of the sensors' primary advantages.

The Capacitive Soil Moisture Sensor v2.0 is capable of functioning with a DC voltage range of 3.3V-5.5V. The output is in the form of analog signals up to a maximum of 3V. The output voltage can be converted into a percentage value by using this method. DS18B20 Waterproof Temperature Sensor This version of the DS18B20 Sensor is pre-wired and waterproofed, making it suitable for use when measuring anything at a great distance or in damp environments. The Temperature Sensor has a measuring range of -55 to 125 degrees Celsius (-267 to +257 degrees Fahrenheit). The cable has a PVC sheathing around it. These 1-wire digital temperature sensors have an accuracy of 0.5 degrees Celsius over most of their measuring range. They work wonderfully with any microcontroller that just has one digital pin available. The sensor calls for two different libraries, namely the One-Wire Library and the Dallas Temperature Sensor Library. When utilizing the sensor, it is necessary to have a pullup resistor of 4.7k, which is required to be connected from the DATA line to the VCC line. NPK Sensor The soil NPK sensor is an instrument that can be utilized for the purpose of determining the levels of nitrogen, phosphorous, and potassium present in the ground. It contributes to the process of figuring out how fertile the soil is. The sensor is designed to withstand prolonged submersion in the ground.

The sensor does not need any chemical reagent to function properly. The sensor has excellent interchangeability, a high measurement accuracy, a quick reaction speed, and it can be used with any microcontroller. You will need any Modbus Module, such as RS485 or MAX485, in order to read the NPK Data. The Microcontroller as well as the Sensor are both connected to the Modbus module. The sensor can handle 9-24V of power. The sensor's precision can be as high as 2% of the reading. The resolution of the measurement system for nitrogen, phosphorous, and potassium is up to 1 mg/kg (mg/l). NRF24L01 Wireless Transceiver Module Because the nRF24L01 is a wireless transceiver module, each individual module has the capacity to both transmit and receive data. It functions at a frequency of 2.4 gigahertz (GHz). A distance of one hundred meters can be traversed by the modules if they are operated effectively. The second iteration of this module, which is known as the nRF24L01 PA+LNA, is equipped with a SMA connector, a duck-antenna, and a unique RFX2401C chip that integrates the PA with the LNA. The module is able to reach a substantially higher broadcast range of approximately one kilometer with the assistance of this range extender chip, in addition to a duck antenna. The operating voltage of the module is 3.3V, but the SPI pins can tolerate up to 5V. Because the NRF24L01 module functions with the assistance of SPI communications, it is compatible with any microcontroller that has SPI Pins, such as the ESP32 WiFi Module or Arduino Boards. To acquire further information regarding this NRF24L01 Module

Let's talk about our project now, which is called Internet of Things-Based Soil Nutrient Monitoring with Arduino and ESP32. In order to accomplish that, we will need to construct two separate circuits. The singular circuit is referred to as a Sensor Node, and it is constructed by combining the Arduino Nano Board, several sensors, and the NRF24L01 Transceiver Module.

Together, the ESP32 WiFi Module and the NRF24L01 Transceiver Module made up the gateway component that we developed. The data is sent from the Sensor Node to the Gateway, and from there it is uploaded to the Thingspeak Server by the Gateway. The circuit for the sensor node as well as its connection diagram are presented below. The Arduino Nano Board, the NRF24L01 Transceiver

Module, the Soil Moisture Sensor, the DS18B20 Temperature Sensor, and the Soil NPK Sensor are the components that make up the Sensor Node. The connection between NRF24L01 & Arduino Nano Board is given below. The sensors are linked to the analog and digital pins of the Arduino board in addition to the NRF24L01 Arduino Connections. Analog pin A0 of the Arduino is connected to the capacitive soil moisture sensor's analog output. In a similar manner, the DS18B20 sensor is linked to the D5 pin on the Arduino. And the NPK Sensor is linked to the Arduino board by way of the Modbus Pin being attached to the 2,3,7,8 Pin on the Arduino. The NPK Sensor can operate on voltages between 9V and 24V. Therefore, the circuit requires an additional supply of power. The Arduino 5V/3.3V Pin is an option for powering the remaining components of the circuit. Gateway Circuit The Gateway is a component of both the Internet of Things-based soil nutrient content analysis and monitoring. The ESP32 WiFi Module and the NRF24L01 Wireless Transceiver Module were used in the construction of the Gateway.

The diagram below illustrates the connection that should be made between the ESP32 Board and the NRF24L01 Wireless Transceiver Module.

Thingspeak Server is utilized in order to carry out the IoT-based IoT soil nutrient monitoring and analysis. Consequently, we are going to have to set up the Thingspeak account. In order to get Thingspeak up and running,

Step 1: Go to https://thingspeak.com/ and establish an account for yourself by filling in the required information. Step 2: To set up a new channel, click the "Channel" button and then fill in

Step 3: After clicking on API Key, a window titled "Write API Key" will appear. Make sure to copy the API Key. This is quite significant, and it will be necessary in the Code Part. Step 4: If you wish to make any adjustments to the display window, you can do so by selecting the "Private View" option. Adding Necessary Library to Arduino IDE

1. NRF24L01 Library This library was developed to have the highest possible level of compliance with the functions that are meant to be performed by the nRF24L01 2.4GHz Wireless Transceiver Module. The SPI bus, in addition to two-chip control pins, are utilized by this chip. 2. RH24 Library For embedded microprocessors, this is the RadioHead Packet Radio library. It offers a comprehensive object-oriented library that can send and receive packetized messages on a wide variety of embedded microprocessors using a variety of standard data radios and other transports. 3. One Wire Library You are able to access 1-wire devices manufactured by Maxim/Dallas using the OneWire library. Some examples of these devices include DS18B20 Temperature sensors. OneWire calls for the use of a single pull-up resistor with a value of 4.7K to be connected between the pin and the power source. 4. Dallas Temperature Sensor Library This is the Maxim Temperature Integrated Circuits Arduino Library that can be used with Arduino. The DS18B20, DS1822, DS1820, and MAX31820 are all supported by this library. Because the Dallas 1-Wire protocol is relatively complicated, a significant amount of coding is required in order to decipher the transmission. In order to obtain temperature measurements from the sensor, the Dallas Temperature Sensor Library is able to provide straightforward commands. IoT Based Soil Nutrient Monitoring, Testing & Results

You are free to begin testing the gadget as soon as you have successfully uploaded the code to the Arduino & ESP32 Board. Now, launch both the Serial Monitor and the Process Monitor to determine whether or not the data transmission is taking place. The data that was read from the sensor is displayed on the Serial Monitor that is located on the sensor node. This includes the value of the soil moisture measured in %, the temperature measured in degrees Celsius, and the NPK Content measured in mg/kg. The data is sent in a wireless transmission to the portion that serves as the receiver and gateway. The information is gathered by the gateway, which then transmits it to the Thingspeak Server. Simply navigate to the private view of the Thingspeak Dashboard in your web browser. You will have access to the information that is being logged into the Thingspeak Server. Using an ESP32, an Arduino, a few different soil sensors, and an NRF24L01 Wireless Transceiver Module are the components that you will

need to put together a basic Internet of Things–based soil nutrient monitoring and analysis system.