Hi,
I was wondering if anybody could point me to a website, etc. that could tell me how to design a simple battery operated light. I'd only planned on using 1 LED and a small battery. Seems like a simple first project (as you can tell from the vagueness of my question, i am a newbie) and I would have a practical use for it once it is done. Any help would be appreciated.
Thanks for any help.
Thank you both for the info. That page seems like a good start to me.
Thanks for pointing out the other group too. This was the first group that came up when I googled. :)
-- You might want to try sci.electronics.basics for some kinder, gentler replies.
This is more a sci.electronics.basics question, I think.
And it would also help if you described more about what you are thinking of and how it is different from what is already available in the market -- what special features it needs (size, operation time, weight, illumination purpose, etc.)
For example, there are flashlights available on the market, for example, using LEDs. I just picked up a pair at US$13.50 each using the Luxeon emitters and o-ring gasketed, all-aluminum housings requiring two AA batteries to operate. From what you wrote, I cannot tell if this would meet your needs, or not.
You might just want something that looks like a burgler-alarm system for your car, where you only want a red LED that blinks slowly. I still cannot tell.
Write more and ... probably in sci.electronics.basics.
Jon
3V lithium + a resistor....? Then you'll apply ohms law. If you don't know that one - thats a good place to start.
(Or maybe a Zetec switcher? Guess not...)
Google is your friend! Say:
/A
Jonathan Kirwan wrote in news: snipped-for-privacy@4ax.com:
Jon,do you have any links to those flashlights you bought? TIA.
-- Jim Yanik jyanik-at-kua.net
I got them at Costco in a two-pack on an aisle end-cap. Just checked on the online store and I don't see them there, though. So it must be a store item and not a catalog item. I'd consider getting some and sending them to you if that's of interest, since I go there two or three times a month. These are way nice flashlights, too. Removing the front aluminum cap, which has a focusing lens in it, I have lambertian dispersed beam that is great for walking down my 1/4 mile driveway at deep night (I can see fully out to my peripheral vision without having to move the flashlight around) or I can put the cap back on and have a "normal" flashlight behavior. The thick, turned aluminum body was a complete surprise to me as I was expecting molded plastic with a "aluminum" coating on the outside. I took a screwdriver and scratched some inner areas to see what came of it and it was just more metal shavings, so... looks real to me.
I don't think these are going to continue being manufactured this way for long. I think it was done this way to get it into the market fast, but profit motives will catch up soon, I believe. Won't see these again, then.
Jon
Jonathan Kirwan wrote in news: snipped-for-privacy@4ax.com:
I think because of the heat sinking requirements of the Luxeon LEDs,you need an aluminum body.
Thee's a Costco near me,,so I'll go check it out.
-- Jim Yanik jyanik-at-kua.net
Doesn't get close to warm. I just measured things at the emitter and I see a about a 60kHz waveform, switching between about 3.0V and 3.6V:
3.6V ****. ****. * ***. * ***. * ***. * * ***. * * ***. * * *. * 3/0V * ''********and so on. The declining ramp falls to about 3.2V, then makes a 0.1V instant drop, then gradually comes down to 3.0V before the next rise. The 3.6V to 3.2V slide lasts 9.6us and the total period is 16.4us.
Peak current is about 0.58A. Minimum current is close to zero (I get about
0.06A on my Tek DMM916 using Peak/Min.)The emitter gets barely noticeably warm to the touch after some time running (5 minutes.) I believe we are talking less than 2 watts average, here, at the emitter. I think regular flashlight bulbs are worse at dissipation.
Okay!
Jon
They're a big-box warehouse-style club format like Sam's Club. You have to pay something like $50 per year to be able to shop there, and there is almost no service. Selection is not great, and packages sizes tend to be huge.
OTOH, if you can live with those limitations, prices and value are very good. Their profit is about equal to the membership income.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Great stuff - we should have such a thing in the .dk hierachy too =)
/Anders
Just tried it with nearly dead (0.8V) AA batteries and it still emits. Not at all brightly, but it does light up a spot!
Well, I checked already at
The circuit type is easy to build, by the way. I believe that "Satcure" was selling some inexpensive demonstration units that work on white LEDs quite well. (He was very generous to me and sent me one to look at because of my interest. I've since had fun monitoring it and exactly calculating the observed waveforms on paper.) His arrangement uses one resistor, one NPN, the LED, and an easily hand-wound transformer. By changing the details of the resistor and the transformer, I'd guess that pretty high-current pulses can be achieved for the Luxeons. I haven't examined the circuit inside the flashlight, though I suspect it works similarly, because it's "down in the tube" and I haven't gotten it out of there.
Jon
see a
Great stuff! Been searching for one of those (highpower LED on AA/switcher) for a long time!
Hmm - wonder if I'll get'em near me (in Denmark). Don't they have a name one can search on the www?
Cheers, Anders
They pay their employees well (I've had discussions with several of them about this, after reading a few articles say so) and the ownership is very liberal minded, contributing to the right causes. :) They are growing well, against the trend of some in their business area and they are doing it while maintaining good employment policies (also in contrast to some.)
Jon
AA/switcher)
Not at
That's the brilliant thing about switchers. I'd expect little or no dimming though ;-)
one
you'll do
Not knowing what I'm searching for I guess not... ;-)
carry --
The alu. casing is kind of tough to do on the kitchen table though...
well.
interest.
waveforms
easily
the
suspect
it out
Zetex makes som nice LED switchers operating down to 0.8V - single cell operation =)
Cheers, Anders
Jon
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