Application of Ba0.5Sr0.5TiO3 (Bst) Film Doped with 0%, 2%, 4% and 6% Concentrations of RuO2 as an Arduino Nano-Based Bad Breath Sensor

Irzaman Irzaman,Brian Yuliarto,Ridwan Siskandar,Ferdiansjah Ferdiansjah,Mochammad Zakki Fahmi

doi:10.3390/chemosensors8010003

Irzaman Irzaman, Brian Yuliarto + Show 3 more

Open Access

https://doi.org/10.3390/chemosensors8010003

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Abstract

Ba0.5Sr0.5TiO3 (BST) film doped with variations in RuO2 concentration (0%, 2%, 4%, and 6%) has been successfully grown on a type-p silicon substrate (100) using the chemical solution deposition (CSD) method and spin-coating at a speed of 3000 rpm for 30 s. The film on the substrate was then heated at 850 °C for 15 h. The sensitivity of BST film + RuO2 variations as a gas sensor were characterized. The sensitivity characterization was assisted by various electronic circuitry with the purpose of producing a sensor that is very sensitive to gas. The responses from the BST film + RuO2 variation were varied, depending on the concentration of the RuO2 dope. BST film doped with 6% RuO2 had a very good response to halitosis gases; therefore, this film was applied as the Arduino-Nano-based bad-breath detecting sensor. Before it was integrated with the microcontroller, the voltage output of the BST film was amplified using an op-amp circuit to make the voltage output from the BST film readable to the microcontroller. The changes in the voltage response were then shown on the prototype display. If the voltage output was ≤12.9 mV, the display would read “bad breath”. If the voltage output >42.1 mV, the display would read “fragrant”. If 12.9 mV < voltage output ≤ 42.1 mV, the display would read “normal”.

Highlights

Halitosis is a general term to describe the presence of an unpleasant odor when exhaling [1].Halitosis is caused by food debris left in the mouth, which is processed by the normal flora in the oral cavity, such as protein hydrolysis by Gram-negative bacteria [2,3]
The Ba0.5 Sr0.5 TiO3 film doped with RuO2 can be used as a bad-breath detecting sensor because it demonstrated a response in the form of voltage changes when exposed to changes in the aroma
The test results demonstrated that Ba0.5 Sr0.5 TiO3 film doped with RuO2 with a dope concentration of 6% was the best film of those tested

Summary

Introduction

Halitosis is caused by food debris left in the mouth, which is processed by the normal flora in the oral cavity, such as protein hydrolysis by Gram-negative bacteria [2,3]. Oral conditions such as the decreased flow of saliva, the blocked flow of saliva, the increase in the number of anaerobic Gram-negative bacteria, the increase in food proteins, a more-alkaline oral cavity pH, and an increased number of dead and necrotic cells in the mouth could trigger bad breath [4]. VSCs are volatile sulfuric compounds which are formed through bacterial reactions (especially anaerobic bacteria) with proteins, which are broken down into amino acids

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