New sensor gets to grips with whiffs

Scientists at the Fraunhofer Institute of Physical Measurement Techniques have created a new generation of semiconductor-based gas sensors that can detect a host of gaseous anomalies.

Scientists at the Fraunhofer Institute of Physical Measurement Techniques IPM are introducing a new generation of semiconductor gas sensors that respond to stale or smoky office air.

‘The new sensors can be integrated particularly effectively in air conditioning systems. They indicate when fresh air needs to be supplied,’ said Harald Böttner, who runs the project. The odour-sensitive mini-devices can also be deployed in warehouses and production plants to report leaking pipes and escaping gases.

The tiny sensor is approximately nine square millimetres in size and is based on the principle that the electrical resistance of a sensitive metal oxide layer changes according to which gas it comes into contact with.

The scientists used four different metal oxide layers, each of which responds to different gas mixes. If, for example, the air in the room contains carbon monoxide because someone has been smoking, the sensor responds.

According to the Fraunhofer IPM, a key feature of the new sensor generation is that it is the first to be produced in thin as opposed to thick film technology. This means that the tiny gas sensors can be manufactured in an automated process like silicon chips, which makes them particularly inexpensive.

The sensors are enclosed in heat-resistant housings and can be combined with other measurement devices.

The mini-sensors are still in the development phase. The research scientists at Freiburg are seeking partners in industry to help introduce them to the market.

The Webnose system is currently being demonstrated at www.ipm.fraunhofer.de/angebot/kms/webnose.