Electric lamp and discharge devices: systems – Time-controlled
Reexamination Certificate
1999-04-21
2001-02-27
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Time-controlled
C315SDIG004
Reexamination Certificate
active
06194847
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to photoelectric controls with built-in timers used to energize lamps at a certain level of darkness for a predetermined amount of time.
Lamp adaptors with both a photoelectric control and a timer have been provided by others. Howe et al, U.S. Pat. No. 5,272,418, for example, describes a device that reacts to darkness by energizing a lamp and starting a fixed timer, which will de-energize the lamp when the time expires. typically in six hours. While the timer is counting down the photoelectric devices is disabled to prevent any flickering caused by reflected light.
Others products have been developed that operate similar to Howe's device except that the amount of operating time can be adjusted with some type of mechanical control which is a part of the product. The control is usually a variable resistor.
An object of the present invention is to provide a method of adjusting the operating time of such a product without the use of mechanical devices such as switches or variable resistors.
Another object is to energize and de-energize the lamp instantly, at full power, without disabling the photoelectric control. Light sensing could then continue while the lamp is energized in case the darkness that was reacted to was only temporary, as might occur during a mid-day storm.
SUMMARY OF THE INVENTION
Disclosed herein is a photoelectric light control that can be programmed by the user for any number of operating hours simply by suddenly blocking the ambient light at the photocell lens for some number of seconds. For each second the light is blocked the bulb of the lamp will be energized for one hour. The logic means, typically a microcontroller, constantly monitors the ambient light level reaching the photocell and is able to distinguish between a slowing changing light level and a rapidly changing light level. A slow rate of change might be associated with the daily setting of the sun, while a rapid rate of change would usually be the result of someone blocking the photocell with a finger. When the ambient light is thusly blocked, the microcontroller enters into a programming mode and starts a seconds counter. The number of seconds counted while the light is blocked will be converted into hours by applying a fixed ratio of 360 to 1 and then will be stored in the memory of the microcontroller as the operating timer for the normal mode, which will result in an hour of operating time, at the next observed dusk, for each second counted.
When the light is unblocked and the ambient light level is higher than the predetermined level of light at dusk, the microcontroller will exit the programming mode and start watching for a slowing changing light level that would indicate dusk. At dusk, the bulb of the lamp will be energized for the number of hours programmed earlier and then de-energized until the next dusk.
If the bulb turns off during the night hours, while the ambient light is very low, the microcontroller will not turn the bulb back on. This is because the microcontroller has been coded to not respond to darkness unless at least five minutes of daylight has been observed. Likewise, the programming mode will not be entered, even though the transition from light to dark was quite sudden, because the microprocessor has been coded to enter the programming mode only within a few seconds following power application to the lamp.
REFERENCES:
patent: 4139801 (1979-02-01), Linares
patent: 4198563 (1980-04-01), Elssner
patent: 4451763 (1984-05-01), Sodini
patent: 4595860 (1986-06-01), Taylor
patent: 4697122 (1987-09-01), Hoffer
patent: 4902906 (1990-02-01), Murphy
patent: 5272418 (1993-12-01), Howe et al.
patent: 5357170 (1994-10-01), Luchaco et al.
patent: 5442177 (1995-08-01), Boulos et al.
patent: 5455488 (1995-10-01), Rhooades et al.
patent: 5670846 (1997-09-01), Hollaway
Tran Thuy Vinh
Wong Don
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