ADESTI: A portable open source instrument for air quality monitoring in surgical operating rooms

This paper presents the design and development of the Air Quality Detection and Safety-Targeted Instrument (ADESTI), a portable smart instrument for monitoring air quality in surgical operating rooms. The system is motivated by the need to detect deviations in oxygen concentration. Such deviations can indicate gas supply leakage or ventilation failure, which are safety concerns during surgical and anesthesia procedures. ADESTI integrates three gas sensors, namely an electrochemical oxygen sensor, a Non-Dispersive Infrared (NDIR) carbon dioxide sensor, and an electrochemical carbon monoxide sensor. It also includes an environmental sensor for temperature, humidity, barometric pressure, and light intensity. All sensors interface with an Arduino Mega 2560 R3 embedded system through the I²C and UART protocols for real-time data acquisition. The measured values are shown on an integrated Thin-Film Transistor (TFT) display. The enclosure is fabricated from Polylactic Acid Plus (PLA + ) by 3D printing to produce a compact and durable casing. The firmware, developed in the Arduino IDE, handles sensor initialization and real-time data acquisition and display. Characterization against reference instruments showed accuracies of 99.71% for O₂, 98.84% for CO₂, and 93.79% for CO, with precision above 99% for all three gas sensors. A key feature of ADESTI is that it combines the functions of four separate commercial instruments into a single low-cost and open-source device. It was field-validated across various surgical procedures at General Academic Hospital, Surabaya, Indonesia, at a total hardware cost of 355.10 USD. All design files, firmware, and the bill of materials are openly available at https://doi.org/10.17632/b6mgd6fgth.1.