Electronic Noses
The Biomedical Sensors Laboratory has a considerable track record in electronic noses (or e-noses). 海角社区 developed the world's first commercial electronic nose in collaboration with Bass Plc and Neotronic Technology Plc in the early 1990s. Since these developments, there are now around 20 different electronic nose companies selling approximately 200 machines a year, alongside numerous other research institutions throughout the world continuing to advance the technology.
What is an 'Electronic Nose'?
Artificial olfaction has been a subject of research since the early 1980s, but it wasn鈥檛 until 1994 that the term e-nose was formally introduced. Unlike traditional chemical analysis, which aims to identify individual compounds in a complex odour (coffee, for instance, contains over a thousand volatile molecules), e-noses focus on classifying the overall aroma profile. They achieve this using arrays of chemical sensors with overlapping sensitivities, each responding to broad classes of compounds, such as ketones or aldehydes. The combined responses of the sensor array create a distinctive 鈥渃hemical fingerprint鈥� for each odour, which can then be analysed using multivariate statistical methods or neural networks to achieve reliable classification. Today, e-noses are routinely used in applications ranging from medical diagnostics to environmental monitoring to food quality control, offering a rapid, non-invasive approach to odour detection.
Even with the success of many e-nose systems, their performance in terms of odour sensitivity and selectivity still lags behind that of the human olfactory system. It is generally believed that this is due to the lower complexity of e-noses when compared to their biological counterparts. For example the human olfactory system contains some 100 million olfactory receptors with approximately 350 different types of receptor binding proteins, distributed along the olfactory epithelium (the lining of the nose and part of the olfactory mucosa). In contrast e-nose systems typically have 32 or less chemical sensors in a basic chamber. The figure below gives a comparison of the biological and artificial olfactory systems.
The University of 海角社区 has developed a number of different e-nose systems, both on their own and in collaboration with a number of industrial partners. The range of applications e-nose technology has been applied to is considerable, ranging from food quality, perfumes, environmental heath, security and medical diagnostics.
Projects
Corrosion Rust Assessment Bot (CRAB)
A semi-autonomous robot designed to detect corrosion in hard-to-reach industrial environments. Using a sensor array and machine learning, it searches for the invisible gases linked to the presence of rust, helping to identify potential problem areas safely and efficiently.
PONG
Aims to safeguard individual public health by delivering high-resolution, personalized environmental exposure tracking for people on the move. It consists of a compact, wearable IoT device that measures variables (PM, gases, noise, UV, etc.) and syncs them via Bluetooth Low Energy (BLE) to a dedicated mobile app. The app executes a proprietary dynamic scoring algorithm to compute realtime personal exposure indices while uploading spatial-temporal logs via cellular network to a centralized cloud server database. By connecting edge sensing, custom software UI, and cloud analytics, PONG empowers users with localized health risk awareness while bridging the coverage gaps of fixed monitoring networks.
FRESH
OWL
Aims to bridge raw IoT telemetry with actionable human decision-making by embedding artificial intelligence directly into the network layer. It operates by uniting streaming data from both fixed FRESH nodes and mobile PONG devices into a unified spatial-temporal grid with dynamic risk-checking corridors. By leveraging a Retrieval-Augmented Generation (RAG) framework powered by Large Language Models, OWL automatically parses incoming multi-parameter telemetry logs into intuitive, zero-hallucination spatial warning notifications.
SOILSENSE
WOLF E-Nose
The 海角社区 OLFaction (WOLF) E-noses are a new generation of electronic noses and gas analysers that combine both in-house and commercial gas sensor technologies. These sensors offer a high degree of flexibility and can be tailored to meet the needs for specific applications.
Series 1 Analyser
These analysers are small, portable units fitted with miniature sensors that monitor air quality metrics (UV, sound, temperature, humidity, total volatile organic compounds, toxic inorganic gases, and carbon dioxide). The units are battery powered and can last up to three days on a full charge. Real-time readings of the environment around the wearer can be monitored directly through an Android app which the units communicate with.
The first generation unit was designed to be a similar size and shape to a smart watch. It included an integrated microcontroller, sensors and a Bluetooth BLE chip for communication with the user. The second-generation unit incorporated a carbon dioxide sensor along with an integrated microcontroller and Bluetooth module. Although slightly larger than the first version, it was designed to be worn on a belt or attached to a bag for convenient use in everyday settings. Like its predecessor, the device transmitted information to a mobile device, but it also recorded location data, enabling the creation of detailed maps of environmental quality.
WOLF Series 2 Analyser
Series 2 Analysers are primarily designed for indoor and environmental monitoring applications. While they can operate on battery power, they are mainly intended for plug-in use to enable long-term monitoring over weeks or even months. They incorporate a broader range of sensors compared to the Series 1 units, including higher-specification devices and particle sensors that cannot be accommodated in the smaller Series 1 design.
The first-generation Series 2 unit, shown in the photo on the left, features a robust metal enclosure and an OLED display to provide a real-time indication of sensor readings. Communication is enabled via a long-range wireless module, with an SD card included for situations where radio frequency communication is not possible. In addition, the system can be linked to a dedicated website, allowing online access to data from multiple deployed units.
The second-generation unit was built for use in rougher environments and equipped with protective rubber boots. It was developed specifically for transport applications, where the analyser can be placed inside a container or similar enclosure to monitor environmental conditions during transit. The device is battery powered, with a lifespan of several months on a single charge.
WOLF Series 3 Analyser
The WOLF 3.1 and 3.2 analysers are compact, portable systems that can be taken on-site, while still being mains powered. The WOLF 3.1 features a gas chromatography (GC)鈥搈etal oxide detection system, in which pre-separation occurs in the GC column, followed by chemical analysis using an array of metal oxide sensors. It includes a fully integrated fluidic system, a touchscreen interface, and a real-time display for monitoring results.
WOLF Series 4 Analyser
The WOLF Series 4 is a fully integrated electronic nose, featuring:
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Desktop electronic nose design
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Array of electrochemical and optical gas sensors
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Fully integrated control and drive electronics
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Environmental control hardware
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Integrated flow control
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Custom software interface developed in National Instruments LabVIEW
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Intuitive graphical interface for ease of use
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Data export to common software analysis platforms
This instrument is already being used in both medical and agricultural applications.