Electronic Nose with Digital Gas Sensors Connected via Bluetooth to a Smartphone for Air Quality Measurements

Abstract

This paper introduces a miniaturized personal electronic nose (39 mm × 33 mm), which is managed through an app developed on a smartphone. The electronic nose (e-nose) incorporates four new generation digital gas sensors. These MOx-type sensors incorporate a microcontroller in the same package, being also smaller than the previous generation. This makes it easier to integrate them into the electronics and improves their performance. In this research, the application of the device is focused on the detection of atmospheric pollutants in order to complement the information provided by the reference stations. To validate the system, it has been tested with different concentrations of NOx including some tests specifically developed to study the behavior of the device in different humidity conditions. Finally, a mobile application has been developed to provide classification services. In this regard, a neural network has been developed, trained, and integrated into a smartphone to process the information retrieved from e-nose devices.

Instrumental Odour Monitoring System Classification Performance Optimization by Analysis of Different Pattern-Recognition and Feature Extraction Techniques

“…Instrumental odour monitoring systems (IOMS) are devices that function as an artificial paradigm of the olfactory stimuli to reveal environmental odours. Their general architecture is composed of a sampling system, along with a detection unit, in which the array of gas sensors and signal processing system are located [ 1 , 2 , 3 , 4 ]. There are wide and different gas sensor technologies currently available [ 1 , 3 ].…”

“…Furthermore, IOMS possessed numerous advantages over sensorial (e.g., dynamic olfactometer) and analytical instrument (e.g., Gas chromatographymass spectrometry, colorimetric method, catalytic, infrared and electrochemical sensors, photoionization detector, differential optical absorption spectroscopy) because it is applicable for in-situ and in real time measurements [5][6][7][8]. Meanwhile, other techniques are Sensors 2021, 21, 114 2 of 16 combined with IOMS, such as pre-concentrator (i.e., silicon-micro), to improve the recognizing capability [9], Bluetooth to a smartphone for remote-controlling applications [4], and GC-MS to identify the responsible gas compounds in odour emission [10][11][12]. IOMS output odour metrics may include odour classification and/or odour quantification [13].…”

E-Nose Discrimination of Abnormal Fermentations in Spanish-Style Green Olives

“…The e-nose equipment was a portable miniaturized device designed by the University of Extremadura (Spain) [ 26 ]. This prototype consisted of four digital gas sensor chips with integrated metal oxide (MOX) sensors: BME680 from Bosch, SGP30 from Sensirion, and CCS811 and iAQ-Core from ScioSense.…”

A novel air quality monitoring and improvement system based on wireless sensor and actuator networks using LoRa communication

“…Besides the challenges of hardware deployment of WSAN systems, software and perfecting communication protocols in sensor networks are also very complex ( Pitarma, Marques & Ferreira, 2017 ; Nayak & Stojmenovic, 2010 ). A series of wireless communication techniques have been proposed for WSAN for indoor and outdoor surveillance applications, listed as Bluetooth, Zigbee, LoRa, NB-IoT, Z-wave ( Saini, Dutta & Marques, 2020 ; Arroyo et al, 2020 ; Chaturvedi & Shrivastava, 2020 ; Liu & Bi, 2017 ; Abraham & Li, 2014 ). For short range environmental monitoring applications, Bluetooth and Zigbee are two suitable techniques.…”

“…For short range environmental monitoring applications, Bluetooth and Zigbee are two suitable techniques. Sensor nodes equipped with Bluetooth communication operate at 2.4 GHz over a maximum distance of 75 m, with peak data rate with EDR is 3 Mbps ( Saini, Dutta & Marques, 2020 ; Arroyo et al, 2020 ). Furthermore, Bluetooth also supports three modes of security with non-line-of-sight communication.…”