Development of RGB LED Based Compact Multipurpose Colorimeter for Hemoglobin Estimation of Blood

In this paper, an inexpensive, portable, lightweight and compact colorimeter has been proposed, which finds application in multiple fields such as biomedical instrumentation, chemical analysis, academics, etc. The instrument employs a customized tricolor RGB Light emitting Diode as light source, and a silicon photodiode as detector. It combines the use of a programmable source of light, and light to voltage integrated circuit, with an open source Arduino microcontroller for wavelength control and data processing. A successful attempt has been made in miniaturizing the bulky optical components of a conventional spectrophotometer thereby cutting down the weight, cost, and tediousness of the instrument. For validation purposes, the device has been harnessed as a hemoglobin analyzer. Observed hemoglobin values were compared with those obtained from a standard laboratory hematology analyzer. Using fivefold cross validation method, a minimum absolute error of 0.024 g/dL and an average root mean square error of 1.283 g/dL was obtained.