Tamper detection circuit and method for use with wearable transmitter tag
US5298884A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 1992 |
| Grant date | Mar 29, 1994 |
| Priority date | — |
| Expiry date | Oct 16, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B21/22
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A wearable tag for use with an electronic house arrest monitoring (EHAM) system, or equivalent, is held against a limb of its wearer by a lockable strap. The tag includes tamper detection circuitry for detecting any attempt to remove the tag by cutting or breaking the strap, even when such cutting occurs in the presence of an electrolyte. The strap has a conductor imbedded therein that is in electrical contact, through known resistances, with respective terminals on the tag. The tamper detection circuit detects any change in the resistance of the strap. Further, the terminals are made of, or coated with, dissimilar metals, so that should the tag be immersed in an electrolyte, and the strap cut, the resulting galvanic action between the terminals allows the cut strap to be detected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.