A laboratory activity for an upper-level undergraduate course in instrumental analysis has been created around LabVIEW. Students learn rudimentary programming and interfacing skills during the construction of a fluorimeter assembled from common modular components. The fluorimeter consists of an inexpensive data acquisition module, LED light source, silicon photodiode detector, photodiode amplifier, colored glass filter, and lenses. Students are asked to assemble a working instrument and program its operation in LabVIEW. The fluorimeter is ideally suited for fluorescein. In addition to a calibration curve, students can investigate the pH dependence of fluorescence from fluorescein and the dynamic quenching of fluorescence by iodide. Students generally work in groups of two or three and the laboratory activity takes 16-20 hours to complete. (Contains 4 figures.)