Sensor óptico baseado em interferômetro em formato de balão com manufatura aditiva para o monitoramento da respiracão

Abstract

This paper presents the development and evaluation of a fiber optic respiration sensor based on a balloon-shaped interferometer with a 3D printed model. Biological measurements play a key role in maintaining a healthy life, as they can predict and indicate disturbances in various body systems, affecting individuals from early childhood to the elderly. Monitoring breathing can detect changes in the early stages of sepsis, systemic inflammatory response syndrome and respiratory failure, as well as monitoring asthma, obstructive sleep apnea and other variations in breathing patterns. The need to monitor breathing has led to advances in data collection methods, including piezoelectric interferometers, capacitive interferometers and fiber optic devices that employ techniques such as intensity or wavelength modulation. The balloon-shaped interferometer was chosen due to its low production and maintenance costs, high sensitivity and resistance to electromagnetic interference. The proposed sensor is highly sensitive to variations in the order of micrometers and has a measuring range of 10 mm. However, to measure a complete breathing cycle, thoracic movement results in an expansion of the prototype of at least 20 mm. Consequently, an additional 3D-printed model in the form of an arc is used, solving the range problem by allowing the fiber to transform substantial movements into small displacements. In addition, the prototype is fixed to the volunteer’s body by means of an elastic strap to allow movement and greater comfort in use. An oscilloscope measures changes in intensity over time with a range of 4.62 dB, and the Optical Spectrum Analyzer (OSA) where a displacement of 8.45 mm can be observed. This sensor can monitor breathing cycles and irregular breathing patterns with high precision and sensitivity, at low cost and with long-term usability, making it ideal for medical use.