PLUMB is a software application that displays a drawn graph on a tablet PC and uses auditory cues to help a blind user navigate the graph. PLUMB is also a project innovating accessibility technologies such as audio schema design and specification for diagrams.

PLUMB was initially inspired by the difficulty to verbally explain a diagram to visually-impaired students when teaching the data structure course. Our goal is to give blind students access to the same diagrams at the same time as sighted students. PLUMB also keeps in mind satisfying other needs of both blind and sighted persons.