StripSense: A Low-Cost Raspberry Pi Grayscale Reader for Urine Reagent Strips—Design, Operational Verification, and Literature Comparison

Reading urine reagent strips against a printed chart is subjective and depends on lighting, viewing angle and reading time. This paper presents StripSense, a student prototype that removes these factors with a light-tight enclosure, ten white LEDs, a Raspberry Pi 5 and Pi HQ camera. Each of the ten pads is read at its own chart time, reduced to one mean grayscale value, and mapped to analyte-specific chart references by linear interpolation; the touch screen shows the value, unit and nearest chart level. In an operational verification with a commercial control solution (one level, one strip lot, three runs), the device ran continuously on the official 5.1 V/5 A supply, completed all ten pads in every run, and reported values matching the control’s labelled levels for 10/10 pads. Three alternative power sources failed. We state plainly what this evidence does not show: no multi-level accuracy, no coefficient of variation, and no sensitivity or specificity have been measured. The design is compared with five published systems. StripSense is not a medical device and must not be used for diagnosis.