Design of a Pulse Oximeter in a Digital Electronics Course

Numerous Digital Electronics subjects are taught when students do not yet have extensive knowledge of Analog Electronics. Finding practices that interest the student and relate to the real world isn't easy in these cases. This work shows the design of a pulse oximeter that is easy to implement for this type of student. The pulse oximeter has very limited signal acquisition hardware and does not use complex analog modules whose operation is not understood by the student. Only a digital processor, resistors, a photodetector diode, and LEDs are required. The design philosophy is based on so-called direct interface circuits, DICs. The implemented circuit uses an FPGA as a digital processor, allowing the obtaining of heart rate, HR, and functional oxygen saturation, SpO
2
. To reduce the digital design included in the FPGA, an auxiliary computer and Matlab software will be necessary to complete the practice and visualize the results. Given that these devices are very successful among the general public, this practice is a very motivating experience for students.