Design of a Portable Pulse Oximeter

Oximetry is a technique that allows the evaluation of oxygen levels in the blood in patients who suffer from a pulmonary disorder or present a respiratory pathology. The main objective of this research is the design of a portable pulse oximeter, which corrects the problems of the oximeter previously developed by the ICID, due to the module used at defined low perfusion levels (modulation index of 0.4% and lower), It had difficulties to synchronize with the patient's pulses and for severe low perfusion conditions (signals with a modulation index of 0.2% and less), the module did not operate. With respect to past designs, this project incorporates an oximetry module produced by recognized companies in this field, thus eradicating the deficiencies of the previous models. The components were updated, using, for example, an LCD screen, a DC / DC converter, optocouplers and the MSP430F2618 microcontroller which is very suitable for this design, as it contains sufficient resources in data and program memory. The design of the schematics of each circuit that makes up the oximeter is carried out. As well as the development of firmware programming, based on the graphic design of the algorithms of the main functions of the equipment.

Understanding Notional Machines through Traditional Teaching with Conceptual Contraposition and Program Memory Tracing

A correct understanding about how computers run code is mandatory in order to effectively learn to program. Lectures have historically been used in programming courses to teach how computers execute code, and students are assessed through traditional evaluation methods, such as exams. Constructivism learning theory objects to students’ passiveness during lessons, and traditional quantitative methods for evaluating a complex cognitive process such as understanding. Constructivism proposes complimentary techniques, such as conceptual contraposition and colloquies. We enriched lectures of a “Programming II” (CS2) course combining conceptual contraposition with program memory tracing, then we evaluated students’ understanding of programming concepts through colloquies. Results revealed that these techniques applied to the lecture are insufficient to help students develop satisfactory mental models of the C++ notional machine, and colloquies behaved as the most comprehensive traditional evaluations conducted in the course.