Re: 12 LED resistance circuit help


"John Fields" <jfields@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:qv3r61pi5lrm9h07ai7bvovk2drcnqva90@xxxxxxxxxx
> On Mon, 25 Apr 2005 20:11:58 GMT, "Anthony Fremont"
> <spam@xxxxxxxxxxxx> wrote:
>
> >
> >"John Fields" <jfields@xxxxxxxxxxxxxxxxxxxxx> wrote in message
> >news:fe8q61pdi7787n4c5c2sqvsqhj77nb9vrf@xxxxxxxxxx
> >> On Mon, 25 Apr 2005 00:43:35 GMT, "Anthony Fremont"
> >> <spam@xxxxxxxxxxxx> wrote:
> >>
> >> >
> >> >"John Fields" <jfields@xxxxxxxxxxxxxxxxxxxxx> wrote in message
> >> >
> >> ><snipped a bunch more side-stepping and invective/ad-hominem crap>
> >>
> >> ---
> >> Translation: "The sonofabitch nailed me, so I'll just shout one
more
> >> insult and pretend he didn't. And now for something completely
> >> different..."
> >
> >However you wish to see it John, though I didn't use any cuss words.
>
> ---
> 'Crap" is a cuss word, and besides, "The thought is the same as the
> deed."
> ---

Crap is just a tad less ugly than FU, don't you think?

> >> >> ---
> >> >> HC4066, about 50 cents, cap about a dime, resistors about a
nickle,
> >> >> diodes about a nickle so, for a one off, that's about $0.70.
> >> >
> >> >Didn't you have a pot in your design?
> >>
> >> ---
> >> Yeah, but it was a nicety. For the cost-conscious, and if the
period
> >> isn't all that critical, 510k +/- 5% will be just fine.
> >
> >I'd go with jumpers on a micro. They're cheap and highly
configurable.
>
> ---
> Not as configurable as a delta R, and good luch with those jumpers on
> an 8 pin chip.

8 pins makes it trickier with just 6 for i/o, but not impossible. 1 pin
to drive the relay leaves 5 jumpers and that still gives me an easy 32
steps to be used however I wish.

> >
> >> >> PCB, transistor, relay is a wash for either system.
> >> >
> >> >Probably wouldn't need a transistor to drive the relay as long as
> >> >5V@25mA will do it. Why not a nice SSR instead?
> >>
> >> ---
> >> Oh, I don't know... Maybe because that's not what the OP of the
thread
> >> in sed you referenced asked for?
> >
> >An SSR doesn't qualify as a relay?
>
> ---
> Not as a relay with mechanical contacts, but it doesn't matter. The OP
> asked for something which could _drive_ a relay, which is what I gave
> him. I showed a mechanical relay because that's what he said he was
> going to use, but if he wanted to switch to an SSR, that would be up
> to him.
> ---
>
>
> >> >> A one off for a micro is gonna cost you the micro, a programmer,
a
> >> >> learning curve and programming and debugging time.
> >> >
> >> >How come the full cost of a programmer and the micro's entire
> >learning
> >> >curve gets factored in every time a micro is mentioned as a
solution?
> >>
> >> ---
> >> Because if you haven't bought/built one and you haven't been
through
> >> the process, then you'll have to buy/build one and go through the
> >> process if you want to play.
> >> ---
> >
> >The same goes for test equipment, soldering stuff etc.... It's just
one
> >more tool that you need, nothing more. A good PIC programmer is less
> >than $100. Compared to the $150 I spent on my audio frequency
generator
> >that I almost never use, it's a great investment.
> >
> >> >It's a one time cost, just like the rest of anyones test equipment
or
> >> >education.
> >>
> >> ---
> >> Yes, of course, but it's a one-time cost and an ongoing effort
which
> >> will will be unwarranted if the goal at hand is to build a one-off
> >> widget with a total cost of, say, $10 or less.
> >
> >But it would be worth buying a DMM, a soldering iron, solder, etching
> >stuff etc.....?
>
> ---
> You'd need that stuff whichever way you decided to go, but you'd only
> need the other stuff if you were going to implement the device using a
> micro, so it would be stupid to go that way when the other way is so
> simple.

For a one off, one-time project either way would be stupid from a cost
vs. return viewpoint.

> >> >I spent less than $75.00 on my programming hardware and the
> >> >dev tools were free from Microchip. My scope cost me more than
$400
> >> >fifteen years ago and it was used then. Nobody worries about the
> >> >thousands of dollars needed for the rest of the stuff you need to
> >> >effectively tinker in electronics, just the $50 for the programmer
> >like
> >> >it's some kind of major show-stopper.
> >>
> >> ---
> >> The keyword there is 'tinker'. If that's _your_ bent, then fine.
> >> Spend away. Understand however, that that's not _everyone's_ cup
of
> >> tea and that some folks only want a simple, inexpensive, easily
> >> realizable solution for a problem peculiar to them. Asking them to
> >
> >Well, I guess that I see PIC chips like you see 74xx's
>
> ---
> I doubt it. I work in both camps as well as in analog, and so far
> you've demonstrated no skill with anything other than some alluded-to
> ability to substitute programming for hardware you admittedly don't
> understand and don't want to "take a lifetime to learn", or something
> like that.

That's a real twisted interpretation of what I said there John. You
might be surprised by what I've been able to glom together over here.
I've even used a few transistors, op-amps and other icky analog stuff.
I'd like to see you search a Dallas 1-wire bus using a bunch of 74xx's.

The projects that I've built are a wee bit more complicated than the
project at hand. They would have been quite difficult to do without a
micro. I'm not saying that they couldn't be done, but they'd have been
real tough even by your standards I think.

I don't make a habit of bragging, but you make me feel obliged to put
forth some kind of evidence of ability. Therefore here are some of my
completed/working projects that I did:

I did an ultrasonic range finder w/lcd display. No biggy, but I used an
op-amp and comparator. A pendulum clock beat analyzer w/lcd of course
w/more analog stuff. Gives ratio of tick/tock beats/min etc.. An IR
controlled temp sensor display that reported readings from various
sensors strewn accros a 1-wire bus onto a graphical LCD screen. This
uses cool looking OCR numbers created from picking apart MS Paint bitmap
files (one of my cooler hacks, I think). All I had for the display was
a data***.

I also did a phone line powered Caller-ID display with a software modem
(that was probably the busiest PIC program I ever wrote with multiple
ISR handlers). That worked ok, but it was never quite perfect (in the
pure sense of the word). Since I don't have a DSO or logic analyzer I
could figure out what the problem was. I chalked it up to eronious zero
cross detects from 60HZ common mode noise on the phone line. Working
with phone line powered stuff is a real pain since you can't ground
anything. It was >99.9% correct, but that ain't good enough when one
bit error wrenches it up in a major way.

My recent ultra low-power project is a temperature data logger that
takes samples every 30 seconds and writes them to a 24C512. There is a
DS1307 RTC and an LM34. The sleep current is <5uA and the average
current is <200uA. I didn't think that was too shabby given the I2C
parts, the LM34, the RTC, the Vref for the ADC and the fact that it woke
up every second to see if it was time yet. You may think otherwise. It
also has a serial interface to pull the info out of the eeproms and to
set the clock/sample rate etc...

I have done many other projects as well, though many of them were never
committed to a permanent circuit board. Since the software is the key
part, they can be easily reproduced if needed. Most were built just to
see if I could "make it work", or to try communicating with some new
protocol (I2C, 1-Wire, SPI etc...) or to utilize some internal feature
of a PIC (CCP, ADC, UART, PWM, etc)

On a side note, I also did build my own 8052 BASIC computer using an
ATMEL 89c52, a surplus latch and 32K SRAM chip. Of course I flashed the
chip myself using the freely available image. I used a 373 as I didn't
know about the 573 latch. Lots of jumpers but it fits on a smallish
radio shack experimenter type circuit board. :-( Pretty neat when the
welcome message first came out. ;-)

Feel free to demand any sort of proof you need to back up these claims.
I have plenty of source code to show you and I could probably even take
a few pictures if necessary.

> >> spend _anything_ on hardware which is going to gather dust after
the
> >> project is finished is, at best, stupid. As is asking them to
spend
> >> time learning how to use it, and to acquire the software skills
> >> necessary to bring the "project" to completion.
> >
> >Burning yet another straw man, you really are a fire bug. I don't
> >recall asking anyone to spend money on equipement to be used once.
>
> ---
> It's not a straw man at all.
> When you insist that using a µC is a better solution than using
> "discrete" logic, then if that insistance bears fruit, the requirement
> for the equipment necessary to implement your solution will become
> de rigueur. If the breadth of the project is the yield of a single
> unit with a cost basically down in the noise compared to the required
> expenditure in time and money to complete the project, then doesn't it
> seem stupid to you to do it that way when doing it in hardware would
> be so much faster and less expensive?

As I already said about this, yes it would be stupid to learn an
unecessary procedure for a one-off project. But then it would be stupid
to undertake the project under those conditions anyway (single unit,
super low cost). You can hardly justify the expense for any toolset
under those conditions. You seem to view the micro learning as a per
job expense, and I see it as a per life expense. As weve covered
before, the only dollar cost in PIC development is in the programmer
(and maybe the software that runs it). The rest of the devtools kit is
free. So all I see is a $75 expense and some hours to learn about
it(which a hobbiest, that's all it's about). Perhaps I am prejudiced
since I have 25 years of "professional software design" experience. ;-)

> > As I "self agrandised" before, if I was adamently suggesting a PIC
to
> >someone, I'd be offering some help to go with it. You can make of
that
> >what you wish.
>
> ---
> From what you've offered so far, I would suggest that anyone who
> decides to go that route find help elsewhere.

You haven't seen any of my work, so what qualifies you to judge it? But
that's what prejudice is all about, isn't it?

> >> >IME, debugging time for this
> >> >project would be virtually non-existent and the end result would
be
> >more
> >> >useful since it would have a much greater dynamic range on the
time
> >> >constant.
> >>
> >> ---
> >> If you think the OP was wrong in asking for what he wanted, then
why
> >> don't you get your ass over to sed and tell him about it instead of
> >> sitting here playing self - aggrandising games and kvetching about
> >> every goddam thing under the sun?
> >
> >Er um, because I don't want to. You really ought to stop trying to
> >control things around here. Ordering people around on usenet is not
> >likely to win you many friends.
>
> ---
> Er um, because you're a chicken*** and you know that if you do you're
> going to wind up getting your ass handed to you. Again.

How so, if I code it up and flash the chips for him? Who's going to
"hand me my ass" then?

> You really ought to follow your own advice, hypocrite. You telling me
> to stop trying to control things around here is you trying to control
> me. Friends I've got. Insignificant gadflies like you I don't need.

Only making an observation, carry on as you see fit. Or is that me
telling you what to do again?

> >> Hint: He doesn't _want_ to be able to change the timing, he just
> >> wants something that'll give him a contact closure, repeatedly,
every
> >> hour or so.
> >> ---
> >>
> >> >> You figure it out.
> >> >
> >> >Your cost may be a little less assuming a PIC 12Fxxx (~1.20 single
> >qty),
> >> >but a 4 bit micro would change that.
> >>
> >> ---
> >> YAFI, LOL! Suggest away, and don't forget to include the cost of
the
> >> programmer and the dev tools, and the time required to learn how to
> >> use them and to learn the instruction set.
> >
> >Programmers and dev tools don't count. We've already covered this.
> >They are in the same category as all other dev tools and electronics
> >equipment you own.
>
> ---
> Other than your just being obstinate, I fail to see why, (without
> even going into the learning curve part of it) you think that paying
> money for dev tools which will only be used once is better than not
> having to pay for the dev tools, yet winding up with exactly what you
> want anyway.

That was never my argument. That's the argument you keep making back
because that's all you think you hear from me. I wouldn't suggest
someone buy dev tools for a one time simple project like this. In fact
I wouldn't suggest that they buy much of anything as the cash outlay for
minimal equipment is still ridiculous for a project like this. I would
suggest they find someone that can do it for them and pay them.

> >> >Outside of the minor cost
> >> >difference, I still feel that the micro offers far more potential
for
> >a
> >> >better end result.
> >>
> >> ---
> >> "Minor cost difference"? You're either trying to sneak some ***
in
> >> there or you can't do, or haven't done, the arithmetic, so I'll do
it
> >> for you: Since the transistor, the base resistor, the clamp diode,
> >> the relay and the PCB are a wash, what's left is $1.20 for your
> >> suggested PIC way VS about $0.63 for my way.
> >>
> >> That comes to:
> >>
> >>
> >> $1.20
> >> -$0.63
> >> ------
> >> $0.57
> >>
> >> which is about 1/2 as expensive as your way. "Minor cost
difference"?
> >> I think not.
> >
> >It's certainly not half as expensive when you factor in a board and
the
> >rest of the common parts. The difference quickly shrinks to ~10% or
> >less, now doesn't it?
>
> ---
> That's a good point but, bottom line, you still save about 50 cents if
> you don't do it with a micro and you don't have to learn how to do it
> and buy all the stuff to do it with if you're not going to do it
> again.

How many people learn to program a PIC for one simple project and then
never use them again? That's got to be a fairly small number.

> ---
> >
> >> Hmmm... Where did I read this:
> >>
> >> "BTW, I feel that a microcontroller would be a simpler, cheaper,
more
> >> reliable (iow better) solution to the problem of resetting the
network
> >> appliances on a regular basis. What do you think?"
> >>
> >> 1. Cheaper? I've just proven that it's not cheaper in onesies, and
I
> >> doubt that with that huge cost differential it could be made
cheaper
> >> in volume.
> >
> >Admittedly for one off, it's pretty hard to be cheaper using an 8-bit
> >micro. A 4-bit proc would do the job, and it would be cheaper. BTW,
> >your quoted prices were a bit low as shown on Digikey, so things
aren't
> >as bad as you wish to make it seem. Of course your price was 70
cents
> >yesterday and now it's only 63 cents, so why am I not surprised?
>
> ---
> Because you're stupid?

Not too stupid to see that you put forth numbers massaged to further
your personal agenda.

> ---
>
> >According to Digikey, the fairchild 4060 is 77 cents in single qty,
the
> >ST part is 55 cents each.

You just called me stupid, yet you don't even bother to comment on this.

> >> 2. Simpler? Since the µC way would require a large investment in
time
> >> in order to climb the learning curve, that can hardly be considered
a
> >> simpler solution for a one-off.
> >
> >What about the electronics learing curve? It's only about 1000 times
> >larger, be for real. That's the same old tired mantra formerly sung
by
> >"professional tube circuit designers" when whining about having to
learn
> >yucky old transistor theory.
>
> ---
> Dumbass, the OP over on SED wasn't interested in spending a great deal
> of time and some bucks on learning how to design a µC timer; what he
> wanted was something quick and easy which he could solder up, probably
> on a piece of perfboard, which would do what he wanted. That's what
> he got, and I got private email from him thanking me for the circuit
> and letting me know that he'd let me know how it worked out. Rest
> assured that I'll post the good news when I hear it.

Yes, we will all be duly impressed that you successfully designed a
ripple counter to reset a router once an hour. Perhaps you can get
another patent.

> Now, do you have any comments on whether it'll work or not? Why don't
> you build one and find out? It'll only cost you five bucks or so and
> we'll learn whether you know how to solder or not. Or wire-wrap. Or
> whether you're just plain ol' fulla ***.

The soldering part was cute, but I'm not just out of school. I've
actually been soldering for a "little while" now. Never was really
interested in wire wrapping, to messy. I do allot of solderless
breadboard stuff though. They're great for knocking out PIC projects.

.

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