Medical instrumentation devices are crucial to determine health conditions in humans. Teaching biomedical instrumentation requires a perfect combination of practice and theory. Therefore, the use of physiological signals simulators such as a %SpO2 becomes important as a teaching strategy. The objective of this project is to develop and implement an oxygen saturation simulator, for use in the biomedical instrumentation courses. The development process began by establishing the requirements of the simulator and designing a graphical user interface to control the simulator parameters. Subsequently, a circuit capable of materializing the simulated signals from the interface was developed, together with a probe or artificial finger that was to be introduced inside the objective pulse oximeter. Finally, the systems were integrated into the simulator.