Digital room light controller
US4277727A · kind A · utility
Inventor
Key dates
| Filing date | Aug 2, 1979 |
| Grant date | Jul 7, 1981 |
| Priority date | — |
| Expiry date | Aug 2, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A digital room light controller comprising optical emitters--sensors, a digital up/down counter, associated transistor--transistor logic(TTL) and solid state relay(SSR) has been constructed. The combination of optical emitters--sensors, TTL logic, up/down counter and SSR, which, when positioned in a doorway of a room, will maintain an electric light bulb in an on or off state depending on the accumulated count in the counter. The digital light controller increments the total count by +1 (i.e. counts up) in the counter when the room is entered and increments the count by -1 (i.e. counts down) when an exit is made from the room. A count of zero causes the interruption of electric power at a selected light fixture, while a non-zero count in the counter insures the maintenance of electric power at the fixture. Therefore a room light is maintained in an off state when the room is not in use.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.