Medical Device for Transcutaneous Bilirubin Measurements

Jaundice is one of the most common conditions in the world, being caused by liver diseases. It becomes pathological when the serum bilirubin concentration exceeds 1 mg/dl and it is visible in the skin and sclera after 3 mg/dl, by turning them yellow. The proposed device measures the amount of transcutaneous bilirubin using the principle of absorption spectrometry, which relates the amount of bilirubin in the skin to light absorption. Three wavelengths are used to measure bilirubin (480 nm, 500 nm, 520 nm) emitted by a multicolour LED. The light beam is reflected by the skin layer to a TCS-34725 colorimetric sensor. A microcontroller running at a frequency of 133 MHz calculates bilirubin using three acquired numerical values, namely three reflected lights: R-red, G-green, B-blue. The calibration of the device is performed by using a medical bilirubinometer via a graphical interface. The device displays the measured bilirubin values on an OLED display. The device is powered by a rechargeable lithium battery (3.7V@200 mAh) through a voltage step-up circuit.