Patent ID: 8296088

Claim:
A system for analyzing a fluidic assay, comprising: a fluidic flow-through chamber; a magnet and a mechanism for selectively positioning the magnet in proximity to an imaging region of the fluidic flow-through chamber; an illumination subsystem configured to illuminate the imaging region of the fluidic flow-through chamber; and a photosensitive detection subsystem configured to image the imaging region of the fluidic flow-through chamber when illuminated, wherein the mechanism for selectively positioning the magnet comprises an actuator and a magnetic field strength sensor, and wherein the system comprises program instructions executable by a processor for calibrating a position of the magnet to which the mechanism is used to selectively move the magnet in proximity to the imaging region of the fluidic flow-through chamber, wherein the program instructions for calibrating the position of the magnet comprise program instructions for: driving a motor to move the magnet toward the imaging region of the fluidic flowthrough chamber; measuring output voltage of the magnetic field strength sensor while the magnet is moved toward the imaging region; storing measured output voltages in a buffer; terminating the motor upon detecting a negligible change in output voltage by the magnetic field strength sensor; and designating one of the stored measured output voltages as a reference voltage for the mechanism to reach in selectively moving the magnet in proximity to the imaging region of the fluidic flow-through chamber.