Using a microcomputer as the core of a monitoring or other clinical instrument is an attractive idea in principle. With the operating characteristics principally defined in software which can be altered or replicated easily and cheaply, the major part of the capital investment is in hardware that can be reused in many different applications.Costing around±400-00 the BBC Model B microcomputer provides a combination of hardware and software facilities that with marketing and product support of comparable quality could make the idea a practicable and cost-effective one for a range of clinical instrumentation tasks.