ambitious project is underway to build the world's smallest electronic nose.
the project succeeds, it is expected that the technology would have many
potential applications in areas such as environmental monitoring, healthcare and
aim is to combine the odour sensors together with the signal processing
components on to a single silicon chip, around a square centimetre in size. The
instrument would require very little power and could be held comfortably in the
palm of the hand.
The project is being carried out by scientists and engineers from the universities of Leicester, Warwick and Edinburgh, with funding from the Swindon based Engineering and Physical Sciences Research Council.
noses have been around for some years, and are used in the food, beverage and
perfumery industries. However, the machines are large, have limited sensitivity
and need to be re-calibrated frequently.
are hoping we can improve on existing systems by following biology much more
closely," says Dr Tim Pearce of the University of Leicester Department of
Engineering, who is co-ordinating the research. "The information processing
of our system is very much inspired by how the olfactory system works in
common with most existing electronic noses, the sensing part of the device will
consist of arrays of electrically conductive polymers. However, the new system
intends to process and interpret the signals in a way much more akin to biology.
sufficient numbers of odour molecules interact with an olfactory receptor neuron
in the real nose, an action potential is induced – a spike of voltage that is
sent down a nerve fibre to be processed by the olfactory pathway of the
brain," says Dr Pearce. "We will design our system to do a similar
thing. When the mixture of odour molecules meets our sensor array, a volley of
spikes will be generated. If there is a high concentration of odour molecules,
trains of spikes will be generated and their frequency will be proportional to
the concentration of the molecule."
'neuromorphic' approach introduces a time factor into the system - the number of
spikes per second - unlike the signals in conventional electronic noses, which
usually ignore time information. This gives the signal processor another layer
of information, which could be useful, for example, when trying to distinguish
between complex mixtures of odour molecules.
Warwick University Professor Julian Gardner is assembling novel mechanisms for
channelling the odours on to the sensor arrays. Professor Gardner says, "We
are taking recent developments in the fields of nanotechnology and polymer
physics to design novel microsystems that are able to mimic our nasal passages
and olfactory sensors. Combining
such technologies with biologically-inspired signal processing methods developed
at Leicester and Edinburgh should lead to a new generation of so-called
micro-noses or a nose-on-a-chip."
Edinburgh Dr Alister Hamilton's team is devising ways to integrate the whole
system on to a single silicon chip. "We are designing analogue circuits
that interface to the sensor array developed at Warwick, and sending the signals
into some analogue circuits that mimic the mammalian olfactory system,"
says Dr Hamilton. "We're using parallel analogue computation strategies
that are derived from biology rather than implementing a conventional digital
processor. By concentrating on very low power consumption analogue circuits we
hope to produce a system with long battery life."
Notes for Editors:
Engineering and Physical Sciences Research Council
(EPSRC) is the largest of the United Kingdom's seven government-funded
research councils. Its mission is to support the highest quality research and
related postgraduate training in engineering and the physical sciences. EPSRC
aims to advance knowledge and technology and to provide trained engineers and
scientists for the benefit of the United Kingdom and the quality of life of its
citizens. It has the further role of promoting public awareness of engineering
and the physical sciences. Website address for more information: www.epsrc.ac.uk/
For more information contact:
Dr Tim Pearce (University of Leicester), telephone 0116 223 1290; email firstname.lastname@example.org
Julian Gardner (Warwick University), telephone
Dr Alister Hamilton (Edinburgh University), telephone 0131 650 5597; email email@example.com
Jane Reck, EPSRC Press Officer, telephone 01793 444312. e-mail: firstname.lastname@example.org
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