ingu Using LEDs in Spectrophotometer Design

Abstract

A spectrophotometer is an instrument that measures the quantitative amounts of light of different wavelengths which are absorbed and transmitted bA spectrophotometer is an instrument that measures the quantitative amounts of light of different wavelengths which are absorbed and transmitted by a pigment solution. The transmission spectrometer which was designed in this thesis uses monochromatic light sources that consist of five different colors LEDs (UV, red, yellow, green, and blue). The detected signal was filtered, amplified and interfaced to PC after converted it to digital by using microcontroller Atmega32. Atmega32 was programmed by using Basic language to control LEDs and measure the voltage drop across the photodiode, this data was sending over RS-232 to the PC. The spectrophotometer circuit was tested using two types of stander tests (pathological and normal) at temperature 37C0; these tests developed by Bio-System Company and passed the tests of ISO. At wavelength 340nm (UV filter) in pathological test the P-value which was obtained is 0.441with percentage 99.2 and at normal test P-value was 0.444 with percentage 99.8%. . As well as in urea pathological test Blue filter (405nm) P-value was 0.806 with 97.9% percentage and at normal test P-value was 0.374 with percentage 96.2%. y a pigment solution. The transmission spectrometer which was designed in this thesis uses monochromatic light sources that consist of five different colors LEDs (UV, red, yellow, green, and blue). The detected signal was filtered, amplified and interfaced to PC after converted it to digital by using microcontroller Atmega32. Atmega32 was programmed by using Basic language to control LEDs and measure the voltage drop across the photodiode, this data was sending over RS-232 to the PC. The spectrophotometer circuit was tested using two types of stander tests (pathological and normal) at temperature 37C0; these tests developed by Bio-System Company and passed the tests of ISO. At wavelength 340nm (UV filter) in pathological test the P-value which was obtained is 0.441with percentage 99.2 and at normal test P-value was 0.444 with percentage 99.8%. . As well as in urea pathological test Blue filter (405nm) P-value was 0.806 with 97.9% percentage and at normal test P-value was 0.374 with percentage 96.2%.