Abstract
I have constructed an array of LEDs of various wavelengths in order to measure the transmission spectra of materials. I used an Arduino to activate each LED individually to measure the transmittance of the particular wavelength through the sample. By taking pictures of the sample backlit by each LED and evaluating them in ImageJ, I obtained the transmittance of light relative to the background. By further analysis in
ImageJ, I was able to create these transmission spectra as a function of the distance across samples. This can be used to observe optical phenomena such as Poisson's spot, a bright spot in the middle of a shadow that occurs due to diffraction.
