Application of thin film barium strontium titanate (BST) in a microcontroller based tool to measure oxygen saturation in blood

Abstract

Tools to measure pulse and blood SpO₂ have been made using thin-film barium strontium titanate (BST) as the sensor. There are three phases in designing a prototype for measuring the pulse and SpO₂. The first is constructing and profiling the optical and electrical characteristics of thin-film BST. From the optical characteristic profiling, it was discovered that there are three wave peaks that are absorbed the most by the film: 450, 600–640, and 900 nm. From the electrical characteristic profiling, it was discovered that the film produced is classified as a photodiode with two sensitivities: exp(–0.0018)/lux when illuminated by white light and exp(–0.0429)/lux when illuminated by infrared light. The second is designing the electronic circuit which consists of an amplifier circuit, filter, and a minimum Atmega328P-PU microcontroller system. From the tests that had been conducted, each circuit succeeded in processing the signal as expected. The third, testing the SpO₂ on 20 patients using the prototype and a standard model Elitech Fox-1 oximeter as the reference tool. The results that were recorded demonstrated that the accuracy of the prototype in measuring the SpO₂ reached 98% in comparison to the reference tool.

Keywords:

• Barium strontium titanate
• microcontroller
• optical properties
• oxygen saturation
• photodiode

Additional information

Funding

We gratefully acknowledge the funding from the Kementerian Riset, Teknologi dan Pendidikan Tinggi, Republic of Indonesia grant 2019, and we also gratefully acknowledge the funding from United States Agency for International Development through Sustainable Higher Education Research Alliances program Center for Development of Sustainable Region (CDSR) 2018.