In this paper, we report on a homemade optical spectrometer using diffraction grating and image
processing techniques. This device was designed to produce spectral images that could then be
processed by measuring signal strength (pixel intensity) to obtain the light source, transmittance,
and absorbance spectra of the liquid sample. The homemade optical spectrometer consisted of: (i) a
white LED as a light source, (ii) a cuvette or sample holder, (iii) a slit, (iv) a diffraction
grating, and (v) a CMOS camera (webcam). In this study, various concentrations of a carbon
nanoparticle (CNP) colloid were used in the particle size sample test. Additionally, a commercial
optical spectrometer and tunneling electron microscope (TEM) were used to characterize the optical
properties and morphology of the CNPs, respectively. The data obtained using the homemade optical
spectrometer, commercial optical spectrometer, and TEM showed similar results and trends. Lastly,
the calculation and measu…