Smart Soil Testing Device Using IoT Based on ESP32 with NPK, pH, TDS, and Electrical Conductivity (EC) Sensors for Crop Suggestion and Fertility Recommendations Soil fertility plays a vital role in agricultural productivity, and continuous monitoring of soil parameters helps farmers make informed decisions regarding crop selection and fertilizer application. This project presents a Smart Soil Testing Device using IoT based on the ESP32 microcontroller, designed to monitor important soil parameters including Nitrogen-Phosphorus-Potassium (NPK), pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), temperature, and water level in real time. The sensor data is processed by the ESP32 and displayed on a 20×4 LCD while simultaneously transmitting the information to an IoT web dashboard through Wi-Fi for remote monitoring. The system analyzes the measured soil parameters to determine the overall soil health and fertility status. Based on the collected sensor values, the device provides crop suggestions suitable for the existing soil conditions and generates fertility recommendations, including the type and quantity of nutrients required to improve soil quality. For example, low nitrogen levels trigger recommendations for nitrogen-rich fertilizers, while abnormal pH values result in suggestions for soil amendments such as lime or sulfur. The system also evaluates EC and TDS values to identify soil salinity and nutrient concentration, ensuring balanced fertilizer application and preventing excessive chemical usage. The proposed system offers a portable, low-cost, and user-friendly solution for precision agriculture by enabling real-time soil analysis, reducing unnecessary fertilizer consumption, improving crop yield, and promoting sustainable farming practices. Through IoT connectivity and intelligent decision-making based on sensor data, the device assists farmers in selecting the most suitable crops and optimizing soil fertility for enhanced agricultural productivity.      

Objectives:  

1. To develop a smart IoT-based soil testing device using the ESP32 microcontroller.
2. To measure essential soil parameters such as NPK, pH, Electrical Conductivity (EC), TDS, temperature, and water level in real time.
3. To display the measured sensor values on a 20×4 LCD and upload them to an IoT web dashboard for remote monitoring.
4. To analyze soil health and determine the fertility status based on sensor data.
5. To provide crop suggestions that are suitable for the measured soil conditions.
6. To recommend appropriate fertilizers and soil nutrients based on NPK, pH, and EC values.
7. To reduce unnecessary fertilizer usage through data-driven soil nutrient recommendations.
8. To improve agricultural productivity by enabling precision farming and continuous soil monitoring.
9. To provide a portable, low-cost, and user-friendly solution for farmers and agricultural researchers.
10. To promote sustainable farming practices through efficient soil management and optimized crop selection.

        The major building blocks of this project are:  

1. Adapter power supply.
2. ESP32 Module.
3. NPK sensor.
4. PH sensor.
5. TDS.
6. EC.
7. 20*4 LCD display.

      Software’s used:  

• Arduino IDE for compiling and dumping code into Microcontroller.
• Embedded C Language.
• Express SCH for Circuit design.
• WEB application.

       

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