A laser doppler velocimeter (LDV) has been designed and constructed for use in measuring ocean water flow velocity in the immediate vicinity of marine organisms anchored inside a water tunnel. The principal innovation reported here is the use of a microprocessor to produce an ’’intelligent’’ instrument which automatically calculates and displays the flow velocity. The resulting electronics design represents a considerable simplification over existing instruments which generally require the use of a separate autocorrelator and/or multi‐channel analyzer (MCA) plus an external minicomputer. The LDV configuration employed is a crossed‐beam design using a 2‐mW He–Ne laser and inexpensive optics. A 48‐channel 1‐bit clipped autocorrelation function is implemented using a modified TTL design reported previously by Chen and co‐workers. A Motorola 6800 micromodule updates the contents of each channel by direct memory access and displays the resulting correlogram on a CRT monitor. The velocity is periodically calculated (±5%) and displayed by LED digits.