Method and apparatus for automatic switching
US4021679A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Oct 22, 1975 |
| Grant date | May 3, 1977 |
| Priority date | — |
| Expiry date | Oct 22, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/94
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method and apparatus for automatically switching a circuit to regulate artificial light in an area. The artificial light is turned on by a person entering the area and reflecting an ultrasonic wave pattern toward a receiver. The light is turned off by a person moving into contactless proximity of a capacitance comparison circuit which utilizes the capacitance of the human body as one of the circuit elements. The ultrasonic circuit operates at different levels of sensitivity, depending upon the existing available light in the area, such as during daylight hours. Optionally, a capacitance comparison circuit may be utilized for both turning on and turning off of the artificial light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.