A coin processing machine for processing coins of various diameters includes an elongate guide surface that guides coins moving along a coin path extending beside and along the guide surface, and sets of first and second coin sensors spaced along the path. Each first and second coin sensor is associated with a respective coin diameter. The coin sensor signals are transmitted to a controller that recognizes the value of a coin associated with a pair of first and second sensors only when both sensors signal the presence of a coin. If only the first sensor signals the presence of a coin, the controller may generate an output signal indicating the presence of a misaligned coin moving along the coin path.