Bioinspired HSV-RGB multimodal integration for wavelength-selection-free colorimetric sensing: a white-LED and RGB sensor for automatic target recognition and versatile detection

Wavelength-selection-free detection (412–715 nm) without prior spectral knowledge. • Automatic recognition enables sample-in-answer-out detection without calibration. • Miniaturized instrumentation (~200 g) achieved via RGB sensor and LED integration. • Cost reduction (thousands → ~$10) with 92.32–107.03% accuracy vs. lab instruments. • HSV-RGB algorithm enables user-friendly, decentralized detection in remote areas. Colorimetric analysis is widely used in food safety but limited in field deployment by bulky instruments and manual wavelength calibration. Herein, we present a portable, low-cost colorimetric device enabled by a bioinspired HSV-RGB fusion algorithm that autonomously identifies analytes and quantifies concentrations without user-defined parameters. Hue ( H ) served as a spectral fingerprint, and RGB values followed the Lambert-Beer law, which was validated across six wavelengths (412, 426, 486, 500, 630, and 715 nm). The device showed high linearity (R 2  > 0.99) with LODs of 6.25 ppb (pesticide), 0.027 mg mL −1 (glucose), and 0.03 μg mL −1 (phosphate), calculated via 3σ/slope, achieving sensitivity comparable to spectrophotometry. In real food samples, measured concentrations agreed with those from the reference spectrophotometric method within 92.32% to 107.03%, confirming its accuracy. Weighing ~200 g and costing ~$10, it enables sample-to-result detection and offers a field-deployable solution for on-site food safety monitoring, particularly in resource-limited settings.