In this paper, the sensor of an optical mouse is presented as a counterfeit coindetector applied to the two-Euro case. The detection process is based on the short distance image acquisition capabilities of the optical mouse sensor where partial images of the coin under analysis are compared with some partial reference coin images for matching. Results show that, using only the vision sense, the counterfeit acceptance and rejection rates arevery similar to those of a trained user and better than those of an untrained user.