The Development and Internal Precision Test of a Portable Soil Sensor Based on Microcontroller for Land Condition Management

Abstract

Efficiency in agricultural land management necessitates portable technology solutions capable of providing real-time soil condition data. In the initial development stages of sensor- and microcontroller-based systems, proving the system's stability and internal precision was a crucial prerequisite before external accuracy validation could be performed.

This study aims to design a portable soil sensor prototype based on ESP32 and verify its internal precision (consistency) and functionality. The system's stability was tested as evidence of the tool's readiness to support land nutrient management decision-making.

The prototype integrates sensors to measure pH, Electrical Conductivity (EC), moisture content, and provide NPK nutrient estimation. A repeatability test (30 consecutive measurements) was conducted on a single stable soil sample in a controlled laboratory environment. The consistency of the readings was analyzed using the Standard Deviation (SD) and Coefficient of Variation (CV).

The stability test showed that the prototype possesses high internal precision. The Coefficient of Variation (CV) for all parameters (pH, EC, Moisture, NPK Estimation) was found to be below 5% the average CV approx 2.5%, indicating excellent reading consistency. The functionality test confirmed that all hardware and software components were integrated and produced a logical response.

This Microcontroller-Based Portable Soil Sensor Prototype proved to be stable and possess adequate internal precision for real-time applications. These results confirm the success of the system's engineering in the initial development stage and provide a strong foundation for proceeding to the external accuracy validation phase and practical implementation in land condition and nutrient management.