Capacitance activated switch device
US7208694B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 2005 |
| Grant date | Apr 24, 2007 |
| Priority date | — |
| Expiry date | Sep 11, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/960755
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A capacitance based switch device employs an electric field imaging device electrically coupled via an electrical conductor to a conductive electrode member that is attached to the door or any other suitable surface. Such electric field imaging device generates a sine wave which is transmitted to the conductive electrode member and produces a surrounding electrical field. Any human body part which enters such electrical field will create a capacitance load due to the body being grounded to a surface. Reduction in distance between the body part and the conductive electrode will increase the capacitance and will decrease the voltage intermediate the resistor and conductive electrode which is an inverse function of the capacitance. Such change in voltage will be detected by a microcontroller by comparing voltages at each end of the resistor and the change exceeding a predetermined threshold will be associated with an output control signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.