Asynchronous serial cuvette reader

摘要

A plurality of test cells in a cuvette is optically measured while the cuvette is manually moved through a sensing light beam. The cuvette is exposed in an open channel exposed to ambient light and is manually moved through the sensing light beam at an arbitrary rate. Abrupt changes in the optical density sensed by the beam are used to trigger the storage of the light beam intensity as an accepted measurement. The abrupt change is determined by comparing the currently read optical density of the cell against a predetermined moving average of previously read optical densities. A modulated sensing beam is received by a photodetector and converted from an analog to a digital signal by a fast A-to-D converter. The output of the A-to-D converter is coupled to a central processing unit which also includes as its input a bar code reader reading from a optically coded strip such instructions which are necessary to describe the number of cells, the test to be determined and other processing or reporting information. Abrupt changes in optical density caused by the passage of the edge of a cuvette cell triggers the generation of an accepted measurement from which an enzyme immunoassay test is performed.