Using simulators to generate physiological signals such as blood pressure allows a better understanding of the fundamental aspects of several biomedical instruments. In this paper, we discuss the design, implementation, and validation of an NIBP simulator. This simulator is low-cost and open-source, and has a graphical interface with valuable information that is not seen in most simulators. Therefore, it can be very useful for students of biomedical instrumentation. Given that these devices usually are expensive, it is difficult for academic institutions to have many of them, which can lead to a lack of availability of equipment during the course projects. Also, because the components are easy to find, inexpensive and all the instructions and schematics are available to share, every student could build their own simulator. We will present a summary of the design process and the system description as well as the validation tests and some conclusions.