If the coin will pass snug- ly through the recess, d, into the box, it must of course be of the same dimensions as a genuine coin, and if a counterfeit it will be lighter.

Marcel Tresanchez, Tomàs Pallejà, Mercè Teixidó y Jordi Palacín. Using the Optical Mouse Sensor as a Two-Euro Counterfeit Coin Detector. Sensors, 2009; 9 (9): 7083 DOI: 10.3390/s90907083 ...

Marcel Tresanchez, Tomàs Pallejà, Mercè Teixidó y Jordi Palacín. "Using the Optical Mouse Sensor as a Two-Euro Counterfeit Coin Detector". Sensors 9 (9): 7083-7096, 2009 (Open Access).

Harry G. Robinson, of Schuylkill Haven, Pa., has taken measures to secure a patent for an improved Coin Detector, which, from its portability, can likewise be used as a receptacle for coins and ...