Smartphone spectrophotometer for point-of-care diagnostics in low-resource settings

Colorimetry based point-of-care diagnostics provide an inexpensive technique for healthcare and environmental monitoring during disaster relief operations. Conventional equipments for measuring colorimetric assays are bulky and expensive, making them unsuitable for usage in low-resource settings. This paper proposes a novel approach for taking colorimetric measurements using a miniaturized spectrophotometer prototype attached to a smartphone. The proposed frugal design is portable, easy-to-use and costs less than US$15. High dynamic range imaging is used to process the spectrums captured by smartphone camera. The proposed algorithm supports JPEG image format, allowing the prototype to be used with a wide variety of smartphone models. In the experimental study, spectrums of color dye and milk samples are imaged. Spectrums obtained are found to be well correlated with the sample color and concentration. By providing accurate and fast measurements, smartphone spectrophotometry enables effective application of colorimetric diagnostic techniques in low-resource settings.