This is a modular spectrometer designed to teach students about the working components of complex scientific instruments and to explore the spectroscopic properties of substances around them. For a detailed description of their use, please visit https://www.colorado.edu/lab/damrauergroup/modular-spectrometer. These parts are intended to be used with a cell phone camera acting as a light-intensity detector. We have designed and used these for an introductory chemistry course at the University of Colorado Boulder and want them to be made available widely during the pandemic for use by any teachers and students who may be working and teaching remotely. The student can mix and match the components to create various instruments. For example: (1) a UV-Vis Absorption Spectrometer to measure what colors of light a substance - such as a dye in solution - absorbs and how strongly it does this for each color {an absorption spectrum}; (2) a fluorometer to measure what colors of light a substance emits after photo-excitation and the intensity per color that it does so {an emission spectrum}; and (3) a spectroscope to measure the spectrum of light sources such as the line spectrum of a common compact fluorescent light bulb.