Multi-wavelength optical sensor for jaundice detection via absorbance difference spectroscopy

We demonstrate a low-cost optical sensor for neonatal jaundice detection using 470 nm (bilirubin-sensitive) and 560 nm (hemoglobin isosbestic) LEDs. The system applies absorbance difference spectroscopy to isolate bilirubin signals in skin-mimicking phantoms, achieving 387mV/mg⋅dL^-1 sensitivity and 13.5% error versus spectrophotometry. Optical characterization confirms 470 nm penetration depth (≈0.65mm) in neonatal dermis. A machine learning classifier predicts risk severity with 99.5% accuracy. Comparative analysis shows a superior cost-performance trade-off versus reflectance-based devices. This work enables accessible hyperbilirubinemia monitoring through optimized wavelength selection and transmission-mode detection.