FEATURE Sensors
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Sensors for digital smell applications
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onsumer technology can imitate many human senses: cameras to see, microphones to hear and touch-sensitive screens to feel – but what about scent? The opportunities for digital smell could be vast and there are gas sensor technologies that detect and identify scent available today. Animal-kingdom noses are full of
receptors that respond to gas mixtures and, over time, the brain learns to recognise a given smell. Today’s gas sensors are designed to digitise smell by imitating the human nose and brain. Electronic noses, or e-noses, require a period of training. They combine arrays of gas sensors with machine-learning algorithms that can identify patterns in response to a specifi c smell. The capabilities of miniaturised sensors and machine-learning software have been growing and have now reached a level of commercial readiness to create a digital smell industry.
The digitisation of smell would be an exciting addition to the sensing capabilities of consumer electronics. The technology has historically had a reputation for being over-hyped, but off -the-shelf devices represent real progress made by this sector, largely been driven by innovations in the fundamental gas sensor technology required, in parallel with the maturity of machine-learning software. The use of arrays in e-noses creates an opportunity for multiple types of gas sensor technologies. Data from well-known sensors such as metal oxide, electrochemical and infra-red, photoacoustic and others can be used by software looking to quantify gas mixtures. At the same time, advanced materials can form ultra-miniaturised sensors with the potential for integration into smartphones and wearables.
More applications Food and drink are another obvious source of smells and a key application for e-noses. For example, the source of an aroma profi le, or diff erences in smell between similar foods, is poorly understood. On the other hand, measuring gases given off by food as it deteriorates or becomes contaminated
22 April 2023 | Automation
By IDTechEx analysts
[Image: Virender Singh for Unsplash]
off ers a way to maintain food quality and ensure safety. It could even help tackle food waste problems, with smell data off ering an alternative to ‘best before’ dates. At an industrial level, ensuring product consistency and quality control could also use smell sensors more broadly, which could threaten the existing supply chain of lab-bench equipment used in this area. Commercial devices suitable for integration into smart-home goods and factories are just now emerging to monitor food and drink. Some manufacturers are beginning to add gas sensors into white goods, and others will follow, to compete in the smart home market.
More than just a smell Beyond quantifying smell, many new e-nose technologies are targeting more sensitive and selective measurements of air quality than existing gas sensors. It is these capabilities that have seen them begin to be adopted into smoke detectors, including premises and perimeter alarms. There is growing interest in air quality and its impact on health, particularly long exposure to low concentrations – this is likely to spur the demand for e-noses. The success of such applications in the smart city and home sectors will arguably rely on eff ective marketing by OEMs. However, there are still e-nose
technology challenges. For example, the use of lower-cost and poor-sensitivity commoditised sensors and higher-value software places a signifi cant burden on training the artifi cial intelligence required. And, the inherently higher-performance hardware for e-noses, such as printed carbon nanotubes, are not yet ready for manufacture at scale. Furthermore, to date the infrastructure to train e-noses and share the data is limited. Whilst images have been simplifi ed into an RGB format, there is not an equivalent for smell so far. This challenge has been identifi ed by some, such as Aryballe, but before the digital smell industry can reach its full potential, more standardisation is needed.
More information “Gas Sensors 2022-2032: Technology, Opportunities, Players, and Forecasts”, from IDTechEx report compares and benchmarks over 15 diff erent gas sensor technologies that can be used within e-nose systems, as well as other applications such as air quality, automotive and safety.
CONTACT:
IDTechEx
www.idtechex.com
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