Apparatus for monitoring a change of condition in a drive belt, such as timing belt, includes a first inductance coil, a second inductance coil, and an electrically conductive loop embedded in the drive belt. Such a conductive wire or strip embedded in the belt material in the form of a closed loop tends...http://www.google.com.au/patents/US6523400?utm_source=gb-gplus-sharePatent US6523400 - Method and apparatus for detecting timing belt damage using link-coupled feedback
