Optical mouse chips-equipped with adequate lenses-can serve as small, light, precise, fast, and cheap motion sensors monitoring optic flow induced by self motion of an agent in a contrasted environment. We present a device that extracts self motion parameters exclusively from flow in eight mouse sensors. Four pairs of sensors with opposite azimuth are mounted on a sensor head, each individual sensor looking down with -45° elevation. The head is mounted on a carriage and is moved at constant height above a textured planar ground. The calibration procedure and tests on the precision of self motion estimates are reported.