A real-time data acquisition system for a hand-held electronic nose (H2EN)

This paper describes an approach towards the development of a portable E-nose device based on an array of metal oxide sensors (MOS) devices, for early on-site dry rot detection on building timbers. A dedicated real-time data acquisition system with a programmable voltage generator, self-calibration techniques and custom visual software programs for a desktop PC and a hand-held computer have been designed and constructed for this application. This paper also describes an example of software calibration to correct source errors for this data acquisition system. Experimental results show that this data acquisition system can accurately measure a large range of resistive sensor responses and is suitable for measuring both conducting polymer and MOS sensors. The custom software also allows users to easily capture, analyse and record measurement data. In addition, the constructed framework for a hand-held computer is based on real-time object-oriented methodology to carry out the functions of desktop PC based instrumentation software. This system presents an effective and user-friendly interface for portable applications.