Hi, I wonder if anyone can help. I would like a design for an LED nightlight which will run for as many hours as possible on at a maximum a single AA cell. The light output is not as important as the time the nightlight will last without having to replace the battery. It is only to light a very small area i.e. just to highlight a step on a stair. Does anyone know of a design which will allow the light to operate for many weeks say 6 to 14 weeks.

Thanks, I am a mere software engineer and I bow in anticipation of reply.
:wink:

 

From a single AA, Hmmm, you could use an LM3909 and have it flash. It would probably last 8 or 9 months.

Using 2 AA and a diode (1N4001) in series with the LED (no resistor) it will be bright and last a while, although I'm not sure about a month.

 

If a flashing LED will work, do a Google search for "1.5 volt LED flasher". You'll find several circuits that will work.

 

I have been hoarding my LM3909s.
I heard they were not in production anymore.


Here is a page were some guy builds a discrete version:
http://home.cogeco.ca/~rpaisley4/LM3909.html

 

Check out this circuit:
http://members.tripod.com/wsimister/ledlite.htm

__________________
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i found a circuit once a while ago. it was called a joule thief (correct spelling there). it uses a led, a resistor a transistor and a ferrite bead that has some wire wound around it to make it into some sort of inductro or something like that.

but thats all that i can remember so i recomend that you look it up

Kieran