Low-Cost Open-Source Spectral Data-Based Color Detection Board for Soil and Mineral Classification

This paper presents an open-source hardware (OSH) solution for spectral color detection targeting soil classification and mineral identification. Traditional methods for these tasks, such as visual comparison with Munsell soil color charts, are highly subjective and prone to human error, while laboratory-grade spectrometers are cost-prohibitive for widespread field deployment. Although recent commercial portable sensors like the Nix Pro have improved in field analysis, their high cost (approximately $300) remains a significant barrier to adoption for educators, researchers, and practitioners. Our system addresses this gap by integrating a TCS3200 sensor, ATmega328P microcontroller, and multi-spectral LEDs (visible/IR) on a single-layer PCB with production costs under $100. Key innovations include: (1) hybrid classification algorithms combining RGB, IR (850nm/940nm), and temporal parameters achieving 95% accuracy; (2) signal settling time measurement as a novel indicator for material density; (3) modular design compatible with Arduino ecosystems. Validated on 120 soil/mineral samples, the board reduces costs by 70% compared to dedicated portable spectrophotometers like Nix Pro while maintaining laboratory-grade precision.