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A feasibility study of the use of ground penetrating radar and metal oxide semiconductor sensors on a mobile platform for security applications

22 February 2012

Emma Newton

The human nose is employed in many industries to evaluate smell or flavour of products such as wines (Gardner & Bartlett, 1999). In the context of security, canines commonly take on the role of ‘sniffer’ by signalling the presence of contraband, such as illicit drugs. However, such methods are costly and they give subjective assessments (Vulicevic, 2004). Electronic noses offer an alternative technology and are based around an array of chemical sensors. Metal oxide semiconductor (MOS) gas sensors are an example of such a sensor and the aim of this project was to study the feasibility of using these sensors on board a mobile platform. 

An appropriate target gas to be analysed was selected and the necessary MOS sensor fabricated. This choice was defined by a material already known to be capable of detecting certain gases that could be easily detected in the environment. A tungsten trioxide (WO3) sensor was selected to detect nitrogen dioxide (NO2). The sensors were tested and calibrated on a gas testing rig to ensure the desired performance. A suitable sensor for a mobile platform was successfully fabricated and calibrated against NO2.

A mobile platform for the MOS sensor was built based on pre-existing design specifications of an in-house gas testing rig. Suitable components for the platform, for example, rechargeable batteries of an appropriate voltage, were sourced and integrated. A WO3 MOS sensor was then integrated into the platform and tested for output. The sensor successfully operated and gave an output onto LabView (National Instruments).