摘要 |
A tamper detection sensor comprises an insulating substrate (2) to one side of which are applied electrically isolated strips (4) of an electrically conductive material, an electrically conductive bridge member (8) interconnecting the strips (4) and secured to the strips (4) by an electrically conductive adhesive (10), and a layer (12) of electrically non-conductive adhesive applied to the one side of the substrate (2) to encase the conductive strips (4) and the bridge member (8) and by which the sensor can be secured to an item (14) to be protected. On relative movement between the substrate (2) and the layer (12) of non-conductive adhesive, the conductive adhesive (10) is deformed whereby the electrical resistance thereof is altered, this alteration in resistance being detected by an electronic monitor (18) connected to the sensor to provide an indication of the relative movement and therefore of tampering with the sensor. |