This work is concerned with the design, construction, automatic control, and optimization of a flow injection analysis (FIA) instrument with chemiluminescence (CL) detection. The project proceeds in three stages: the construction of the detector, the construction and control of the flow system, and the chemical measurements. The light detector is based on a low-cost commercially available photodiode. Control of the flow system and data acquisition is performed through an interface card controlled by the LabVIEW software tool. In developing the detector and the flow system, students were acquainted with different aspects of instrument design and control, such as light detectors, operational amplifiers, analog and digital filtering, computer interfacing (digital-to-analog converters, analog-to-digital converters, digital input–output), and graphical programming. The apparatus developed was used to optimize the chemical and instrumental variables of a FIA–CL method for the quantitative determination of Co(II).