A foreign object detector for a note validator, the detector includes means defining a note path and gate means in the note path operable between an open position for allowing a note to pass the gate means and a fully closed position for preventing a note from passing the gate means. The gate means is biased towards the fully closed position. The foreign object detector also includes sensing means for detecting when the gate means is in the fully closed position. In the fully closed position, a leading edge of the gate means extends outside the note path and is received within a recess in the means defining the note path, whereby a foreign object in the note path obstructing the recess prevents the gate means from reaching the fully closed position, the sensing means thereby detecting the presence of the foreign object in the note path.