Personal microcomputers, having already made a very significant impact on business and data processing applications of computing, are now showing considerable potential in the automation of simple laboratory tests. Such tests require a combination of data-processing capability for sample identification and user-friendly interface for display of results and test limits coupled with real-time control of the measurement process. These are just the combination of characteristics available in the personal microcomputer and the relatively clean environment of the laboratory means that they provide an ideal vehicle on which to base the design of laboratory automation systems. This communication describes the use of a PET microcomputer as the controlling element in two typical laboratory applications, namely tensile testing of aluminium and additional control facilities for an air pollution monitor based on spectograph techniques. Each application is described briefly with emphasis on the assembly-code software techniques necessary to overcome the lack of computing speed in the interpreted BASIC which was used for the rest of the software. The benefits of using a common approach to the hardware interfacing are also discussed.