Patent ID: 7978444

Claim:
A method to determine location of a specific magnetic bead, comprising: providing first and second sets of conductive lines, all lines within a given set being parallel to one another and no line in the first set being parallel to any line in the second set, said first and second sets being disposed so that the two sets intersect without contacting one another; providing, at each intersection, a detector that signals the presence of a magnetic field through a change in said detector's electrical resistance; binding said specific magnetic bead to a detector located at an intersection between said first and second lines; by external means, providing a first static magnetic field; passing an alternating current through said first line, thereby generating, around said first line, an alternating magnetic field having a first frequency, whereby, through adjustment of said first frequency, all beads that lie on said first line will be brought to ferromagnetic resonance at a second frequency; and passing a direct current through said second line, thereby generating around said second line a second static magnetic field, whereby said specific bead will be brought to ferromagnetic resonance at a third frequency that is different from said second frequency, thereby signally that said specific bead is located at the intersection of said first and second lines.