  In this paper, we present the details of the development of a smartphone
spectrometer for education using a 3D printer and characterized the performance
by comparison with a paper craft spectrometer. The optical design and the
narrow slit used in the build resulted in the formation of accurate images of
the slit on the image sensor leading to a superior resolution compared to the
paper craft spectrometer. Increasing the exposure time of the phone's camera
revealed the fine structure of a spectrum with high resolution. The baffle
structure inside the spectrometer proved to be effective in removing noise when
the exposure time was increased. We expect that the 3D printed smartphone
spectrometer proposed in this paper can be useful as an education tool for
students to understand the various aspects of light, atoms, chemistry, and
physics.
