Smartphone Spectrometer for the Galaxy S4

I made this spectrometer to fit my Galaxy S4 phone after doing a class lab in spectrum of sources and diffraction. The pictures above are the spectra of the sun, actinic, 6700k, 10000k T5 bulbs, a Fluorescent bulb and a mercury vapor lamp. I used a free android app called SpectraUPB to plot the spectra but the calibration from pixels to wavelength is not perfect. A better free online spectrum analysis tool is at https://spectralworkbench.org/ or possibly try using matlab or gimp.