Edward J Ellis

US Patent:

46299416, Dec 16, 1986

Filed:

Jan 7, 1985

Appl. No.:

6/689315

Inventors:

Edward H. Ellis - South Euclid OH
Marilyn S. Ellis - South Euclid OH

International Classification:

H05B 3702
H05B 3904
H05B 4136

US Classification:

315153

Abstract:

A first phototransistor (20, 20') is mounted on the structure such as a home (12) or a garage (14) to sense the level of ambient illumination. A second phototransistor (22, 22') senses both the level of ambient illumination and illumination from the headlights of an approaching vehicle or the like. The phototransistors are arranged with a pair of resistors (54, 56) in a balanced bridge (50). A central bridge junction (52) assumes a higher potential when both phototransistors are illuminated the same, whether light or dark, and a lower potential when the second phototransistor is illuminated more brightly than the first. In response to the uneven illumination of the phototransistors, a timer (60) produces an output signal for a preselected duration. An optic coupler (90) gates a triac (92) conductive for the preselected duration of the timer. The triac is connected in series with exterior security lights (24, 24') for illuminating the area adjacent a driveway, home, and garage to provide a lighted path for the vehicle occupant after disembarkation of the vehicle.