Cool, right off the bat, while all the posts are loading, I already hooked
up with some Schematics sites. Still downloading teh whoel NG (over 500K
posts going back to at least 2003...)
If I had any idea how to find a qualified person, I'd pay for tutoring!
I'd actually emailed several places to ask about having the circuit
designed, i.e. hwat it'd cost, but no replies - I htink the project is just
too small to be of interest to professional designers (and any who might be
interested would prob be way too expensive for me). But it'd be
interesting if I could find s/o who could look at the App Notes and
Datasheets I'm using, and explain to me how they work so I could get soem
knowledge that I could generalize. I have no knowledge whatsoever of the
eelctronics world, so it's not really feasible for me to "just ask my
friends" (esp. as, in real life, I'm very introverted). Much of the time,
I'm not even sure how to ask the right question, because I don't "speak the
lingo" - I didn't even know what an "LED driver" was until someone
mentioned it, and I looked it up, so until that point, I didn't know how to
ask about it.
Maxim's notes give an example of a switch-mode circuit using th e DS2715
that, to be bluntly honest, looks to me like a plate of spaghetti, and I
don't know enough to how to simplify it (or if that is even possible...)
GAWD but I hate having limitations =>:-p ARRGH!!!
Anyhoo, I'll look into that group, thanks!
Cool! Do you charge by the hour o by the job? What is your rate (pref in
US dollars)? Would an International Money Order be the best way to send
the fee? (I don't have a PayPal account because I don't trust PayPal.)
What I can do is either (1) work up the whole circuit and send the file, or
(2) send the links to the literature on the Maxim site. As I understand
what the Maxim folks told me, the various example circuits I've been
looking at on the Maxim site can be daisy-chained tgether (tho' I'd also
like to toss in a photoresistor so that the LEDs won't start running off
the batteries until Dusk), but the battery-charging circuit is the one I
need the most help with, because it outputs 1070mA, which I *think* (but
don't actually know) is too much for the batteries (at this point, 1500mA
AA 1.2V NiMH, but I can also get 2500mA AA NiMH batteries). ALso, the 5V
Supply generating circuit outputs 500mA at 5V, so I don't know whetehr I
need to alter the battery-charging circuit for that, since the charging IC
accepts an input Voltage of between 4.5 min and 16.5 max, but I'm, having
difficulty figuring out whether a *current* of 500mA will operate the IC
(not sure whether I have ot add up *all* of the current vlues for the
various things listed in the "DC Electrical Characteristics" chart, or
Frankly, it amazes me that people can figure all of this out, and amazes me
even more that all of this was discovered <!>
I've been reading a bit to try to get a feel for the group before horning
in ;) Looks pretty good so far, thanks again for the recommendation.
I've got the basic concepts down pretty well (and wrote up "crib sheets"
for concepts and formulae I need to keep straight but might not remember
right), and can figure out basic things using Ohm's law and other basic
relationships, but wht confuses me are (1) how to trace circuits to even
try to figure out how the designers did/approached the various calculations
- I keep assuming I'm supposed to start from the "input" point, but none of
the circuit diagrams indicates which way to continue to trace when things
branch off, and (2) it sometimes seems to me that, for example, resistors
are placed "behind" the components to which the resistors are supposed to
be controlling the voltage, so that appearance of "horse before cart" adds
to my confusion. I couldn't visualize it when I took Physics 30 yrs ago
<!>, and I still can't. It'd be a lot easier on us Rubes if little "charge
flow arrows" were noted on circuits <G!>
So, as you can see, the complexity of this is way beyond me:
http://www.maxim-ic.com/appnotes.cfm/an_pk/4180 , the part of interest
being the very last section, "Powering the Load Directly from Batteries".
I understand the *concept* - they are using various "feedback loops" so
that the IC can sense that the batteries are charged, and switch off the
charging flow and turn on the LEDs ("load") to run off the battery. But I
don't knwo enough to figure out whether I need to change it to handle the
batteries I want to use, and if so, how or where to make the changes.
Right now, I'm entering all the parts listed on the three circuits into a
spreadsheet so I can add up the costs and come up with a good estimate of
expenses, but I'm also trying to figure out whether I actually *need* to do
it all as is illustrated in the various datasheets and Application Notes...
Yeah, the Maxim site has been up on my computer almost continuously for
over a week <L!> They do have a lot of great info, and they even answer
email, which is IMO pretty darn impressive.
Is this something like that?
|<--Booster Circuit (utilizing MAX866 and MAX1771)
| | (as per AppNote1029)
| battery pack-------MAX1848-----LEDs
| (2-3 NiMH) | 4 or 6
| | | |
Thanks, I need it! <LOL!>
OOTH, I tend to learn better when I'm learning through an application, as
opposed to just having to memorize a lot of facts, or solve textbook test
questions that don't relate to anything. If I can manage to pull this off,
I can see it as a step towards understanding a lot more about both
alternative energy, and real-life "electric stuff" ;) , both of which are
potentially useful, and at the least, interesting. I have to say that, the
more i learn about this small project, the more sense whole-house solar is
making, due to the "demystification" so to speak :)
The trippiest part is doing it in parallel with learning the variosu new
creative techniques using glass, and also trying to do design work using
those techniques (the fusing efforts being much elss successful on my part
than were teh copper foil designs, but it's all a learning process). I
also designed and am building a simple, collabsable-portable splatter-
enclosure to use while grinding glass (it splatters terribly, and i don't
have a real studio area I can nmess up). All I need to do now is throw in
learnign a new language, and the Mental Mayhem will be nearly complete
Now you know why I seem so confused sometimes - I am! ;)
Onwards and upwards -
Well, *that's* scary =:-o
Sorry for the delayed response, BTW, had a lot going on...
Just a few comments at this point - I did post my "flow chart" and
questions to the sci.electronics.design newsgroup, so I'm going to wait and
see what comes out of that.
I've got this thread marked as "KEEP" in my newsgreader, so what I'll do is
see whether anyone in that NG has some design suggestions, and take it from
there. I might just go ahead and build the thing, and see whether it
works, and thake it all from that point.
It's isn't going to be the cheapest thing, but ti will still be only about
1/4 or so of the total price I'd be asking for the lamps/lanterns/whatever
- I dunno what to call them; they're supposed to be "garden lights", but
given (1) the sizes I intend to make, and (2) that fact that the 6 LED
versions should yield around/nearly the same number of Lumens as a 40-watt
incandescent light bulb, they could prob also be "table lamps". One of the
problems is that, when people hear "solar garden light", they think of
something small and dim (even tho' they've gotten brighter as LED
technology has improved). Which is, I think, the reason that I've gotten
so many suggestions to "just go buy a cheap one, take it apart, and put the
guts into your item".
Of course, some other folks suggested things like patent applications and
copyrights...but I don't really think I can take circuit sdesigns from a
company website, and then get a patent just becasue I glombed them together
and schlepped them into something I make <LOL!>
OTOH, who knows these days...
ANyhoo, thanks for the info re: your consulting, and so on. It's good to
know that such a resource is out there :)
Thanks :) - hard to believe that I was able to make it that
comprehensible ;) THe Strattera must be working <L!>
I hadn't thought of it that way, but it does make sense. Especially
since I'm trying to respond to a desier/need expressed by everyone I've
polled. If I *can* get the brightness I'm trying for, the things could
also function as a sort of emergency lighting, as well as boutdoor table
and garden lighting. ((I like Multi-Use items.))
Ugh...got too many of those as is ;)
My only "manufacturing" will be Yours Truely.
At least one thing I know to *never* do is fall for any of those "we'll
help you patent and market your invention" scams. I've known a couple
people who got burned that way :(
OK, that is *too* nifty ;)
I can imagine using it in lighting units from public to private, and from
utilitarian to artistic - and imagine if it could be combined with
hurricane-resistant glass! I can envision everything from blunt-ended
tubes ("Light Torpedo"), to art pieces, that incorporate the system...sorta
gets me all tingly <LOL!>
Seriously, tho', very cool, thanks for the link!
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