Hey all!

Greetings from Finland!

I considered also a step-up/charge pump from batteries to use w/Luxeon and tried several designs; I ended up using single cell Li-battery. Charging is done with one SO8-housed SMD chip, it uses two C-size tantalum caps and has a charge indicator LED. The device has also a D-FF as soft power switch (few 0805 pulldowns) and a SHDN-featured 250mA current limited stepup (3 tant. caps only, no inductors). The PCB is square, 2cm per side(!), height is approx. 4mm and LX blows out pretty bright. This configuration also drives the LX at 250mA till the battery drops dead. The whole thing has been encapsulated inside shrinking sock and is smaller than most rectangular-shaped 1xAA-cell stepup lights and gives damn lot more light. The Li-battery lasts also for about 4hrs.

Comments?

BR,
R.S

Comments? Yes, I want one. Can the current be raised to 350-400ma? If not, I want one. Did I say that already?
Welcome to CPF. May your time here be fruitful.

Very cool.

What type and size battery are you using?

If you could provide more details that would be great!

-WayneY

Photos Please

Ugh,

How to add #¤$$ pics to this reply?? Don't have them anywhere up, so here's some brief in ASCII:

The charging is done w/MAX1811. As I mentioned before, 2 caps and charge indicator LED. That's it. No inductors.

The stepper is of type MAX682. Caps for in, out and one transfer cap. Add a resistor to drive SHDN from somewhere and you're done. The output current is fixed to 250mA as this device is a cap-based charge pump. But, you can stack for example two of these in parallel to get .5A...

Oh, the battery type is an ordinary 1-cell 1000(?)mAh 4.2V(? or wasit 4.1? dunno, but it charges perfectly...) Li+-pack. Took one Nokia battery apart hehe...

The charge pumps SHDN is driven with low voltage D-Flip Flop to get a 'soft' power switch. Apply rising edge through a switch to CLK (remember pulldown ~10k), complementary output is hardwired to D and you have the simplest state machine in da world. Push ->on (stays on), push ->off (stays off). Handy. Luv Maxim 'cos their free samples...

You'll have sum pics after a clear explanation howto

BR,
R.S

R.S, you need a pic host from where you can link to. there are several out there, but not all allow linking. Obviously, I'm using a dutch one, but you should be able to figure out how to register, should you want to use it. here is a link .

you can mail me if you want me to set it up for you, or mail the pics and I'll put them up for you

Edit
image station seems to work too, and it's in English...

Sounds VERY interesting.

I think a lot of us would like more details- (I am especially interested in the LiIon charging system.]

If you could post more information and perhaps some photos, I know I'd appreciate it, and I am sure many others would too. If you could give some pricing information, that would be helpful too.

Ugh,

Sent images to *BlackBart*, contains one completely hand-crafted schema plus a pic w/ no light and one with lite. Images captured with ye olde Mavica, but they are still quite clear. Let's hope they arrived OK to him.

BR,
R.S

HI R.S.-

love the idea! Simple and elegant. Post a circuit diagram when you have a chance!

Best,

Michel

R.S , here they are...




Btw, there is a nice and easy circuit drawing program called Splan, from Abacom.
Not sure if you know German, but the program is very intuitive, so even if you don't, it will take you only a couple of minutes to understand it ...

Hey,

Thanks, BlackBart!
ye ole' hand-crafted is well-crafted

Comments?

Comments? Yes. The circuit is beyond my skill level. Do you want to market some already built, say, to me?

Glow Bug mailed me an enhanced pic of the light.
Thanks

Sorry, sunspot!

Built the gadget from samples to wire wrap-board and have no intention to make a PCB for it. But, it's quite simple to construct. Just throw in the chips, add coupleo caps. Few wrap wires to cover the schematic and you're done.

BR,
R.S