07459871 is referenced by 106 patents and cites 240 patents.

A piezoelectric debris sensor and associated signal processor responsive to debris strikes enable an autonomous or non-autonomous cleaning device to detect the presence of debris and in response, to select a behavioral mode, operational condition or pattern of movement, such as spot coverage or the like. Multiple sensor channels (e.g., left and right) can be used to enable the detection or generation of differential left/right debris signals and thereby enable an autonomous device to steer in the direction of debris.

Title
Debris sensor for cleaning apparatus
Application Number
11/860272
Publication Number
7459871 (B2)
Application Date
September 24, 2007
Publication Date
December 2, 2008
Inventor
Daniel Ozick
Newton
MA, US
David A Cohen
Brookline
MA, US
Gregg W Landry
Gloucester
MA, US
Agent
Fish & Richardson P C
Assignee
iRobot Corporation
MA, US
IPC
B25J 5/00
G05D 1/00
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