Night light circuit?

Want to build a simple one or two cell ...single LED circuit that would sit on a shelf in a bathroom...far away from any outlet....to provide very low level light for late night bathroom visits. I've built a few Joule Thiefs, but they seem to eat thru AA batteries pretty quickly. I could do with even lower lumens. Anyone have a simple circuit?

Does it have to be a white light ? if not then use two alkaline cells and the brightest amber or yellow LED that you can get together with a series resistance to limit the current to say 1ma. Provided that a good bright LED is used, then 1ma is enough for a night light.
D cells will give a run time of a couple of years 24/7. AA cells about 100 days.

If you want a white light, then 3 cells are needed and a white LED.

On the joule thief front, I've got an almost endless supply of used AA batteries powering them but I change batteries maybe every 3 days. None of the batteries are new and the brightness is very low but that's all I need. Want to extend the run? Try using 2xAA in parallel if you can match pairs.

The other joule thief is the zetex 380 driver and the inductor of your choice. Use 2xAA for some real nice performance. One of our forum members sells some boards with this, and a kit too.

I've picked up a similar driver from a $1 AAA light. Unknown Chinese copy of the zetex but 2xAA works like the zetex.

Do you run it continuously? OR do turn it on and off as needed?

Do you have room for three D cells?

Here is a review that I did on a three D cell lantern with run times and outputs of an XB-D emitter.
It uses a simple resistor. I can get the values for you if you want.

Mr Floppy said:

On the joule thief front, I've got an almost endless supply of used AA batteries powering them but I change batteries maybe every 3 days. None of the batteries are new and the brightness is very low but that's all I need. Want to extend the run? Try using 2xAA in parallel if you can match pairs.

The other joule thief is the zetex 380 driver and the inductor of your choice. Use 2xAA for some real nice performance. One of our forum members sells some boards with this, and a kit too.

I've picked up a similar driver from a $1 AAA light. Unknown Chinese copy of the zetex but 2xAA works like the zetex.

Click to expand...

If you change batteries every three days, why aren't you using rechargables?

DIWdiver said:

If you change batteries every three days, why aren't you using rechargables?

Click to expand...

I get a lot of half spent alkaline batteries. Most of them are AA.

My favorite circuit for draining batteries is this simple two transistor boost. When made with quality components, it will last several days on a nearly depleted AA cell. Another great little circuit is the Diodes ZXLD381. You can change the current to the LED by using a different value inductor.

Below are some images of some circuits that I have built using SMT components. This may give you some ideas of how to mount the circuit to your battery.

Completed circuit board for the battery drainer.



Two transistor circuit, OM4558 IC circuit and two transistor boost with CREE XP-E


Two Transistor circuits


Two transistor boost components and schematic.

Loving those pics, datiled! Thanks for posting! I love minimalist hacky builds!

More great inspiration from the datiLED labs.... Now I need a rainy day to build one of these.