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'[EE]: Light bulb make square to sine wave'
2004\05\17@104214 by llile

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Matthew,

>P.S. any tips/hints are welcome for rules for posting message, or
protecting myself from spam etc.  I mostly have just been reading the list
from the safety of google groups.

Welcome to the list!  Here are some things that might help make your
experience more satisfying:

1. Notice that I put a topic tag [EE]: in the subject of the email.  These
wierd tags are used by some PIClisters to sort out some of the noise on
the PIClist.  Read more about them ont he PIClist home page
http://www.piclist.com  It is considered polite to add the tags, since it helps
some of the list members reduce the clutter in their inbox.

2. Go ahead and post any technical question, no matter how simple or
basic!    Many people new to the group are reluctant to ask things for
fear of being flamed.  We are here to help each other learn about
electronics (and physics, and philosphy, and cows, and languages, and
amateur rockets.. and the difference between Australian and New Zealand
Slang Words,  and a lot of other stuff) .

3. It helps us a lot if questions also have some background information.
Many new posts will say "why doesn't my program work?" without much
background, which makes answering difficult.  An easier question to answer
is "I have set up a watchdog timer with such and such code but it doesn't
work like I understand it should, it works like so-and-so.  Am I missing
something?"  The devil is always in the details.

3. We are here for the long term.  I've been on this list 9 years, and I
am one of the new guys.  Remember that people you talk to here will
probably be here to talk to you a year from now.  Most of us are
professionals, don't have a huge amount of spare time, and like to get to
the facts and the answers.  From your post I can tell that you are a
person who expects a certain level of civility and politeness, and these
qualities are appreciated on this list.

4. As stated on the PIClist.com home page, posts about religion or
politics are discouraged, since there is no settling such questions.  We
usually bend these rules in the wake of signifigant holidays or gigantic
international disasters, but only for a day or two and then James will sit
on us and make us talk about electronics again.

-- Lawrence Lile





Matthew Brush <spam_OUTmatthewbrushTakeThisOuTspamYAHOO.CA>
Sent by: pic microcontroller discussion list <.....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU>
05/17/2004 07:23 AM
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       To:     PICLISTspamKILLspamMITVMA.MIT.EDU
       cc:
       Subject:        Light bulb make square to sine wave


Hi all,

I'm new to the PIClist ... well, I've been reading it for months now, just
not posting.

I'm sorta sending this message for 2 reasons;

1. I'm not used to this type of list, I usually just use outlook for
newsgroups or whatever.  So I wanna make sure this works.  Let me know if
it does.

2. Keep reading...

I'm just starting to look into making a little serial to dtmf modem dealy
with a PIC16F628 or similar.  While doing some research, I came accross
some brief information about a light bulb being used to convert a square
wave to a sine wave?  or am I on crack?  I believe the idea was conceived
by Hewlett or something.

I'm pretty sure I'll be able to create a good enough sine wave with PWM
hardware and some filtering, but I still though it might be interesting to
look into this idea.  It's used as a voltage variable resistor or
something?  Is this similar to those things I've seen in guitar effects
circuits that use an LED and a photo-resistor inside a piece of heatshrink
tubing?

Anyway, please excuse my ignorance, I'm an MCSE ... nuff said ... hehehe

P.S. any tips/hints are welcome for rules for posting message, or
protecting myself from spam etc.  I mostly have just been reading the list
from the safety of google groups.

MJ Brush

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2004\05\17@112051 by llile

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Matthew,

I believe Microchip was making the first PICs by that name in about 1989
time period.  Not real sure. Someone else on the list will probably soon
post with exact figures on these items, these are all from my (leaky)
memory.

Some time before that they were a division of another company, and the PIC
architecture had been settled on in the late '70's or early '80's.   I
started messing around with them in 1991-1993, IIRC, and soon my hobby
turned into a job.

As far as being born 20 years earlier or later?  I often think of
particular periods in our industry, such as the late 70's when just
writing a game like PAC-man could make you a rich man, or when some
college drop-out running a rag-tag company full of pony-tailed,
fashion-impaired software geeks was approached by IBM to write MS-DOS, and
imagine it would have been a better time to be doing this.  However,
amazing and wonderful things are discovered every day, and 20 years from
now we may look back on 2004 as the golden age of something or other.  And
you are likely to hear about it here first from the people designing it.

-- Lawrence Lile





"Matthew Brush" <.....matthewbrushKILLspamspam.....yahoo.ca>
05/17/2004 10:03 AM


       To:     <EraseMEllilespam_OUTspamTakeThisOuTsaltonusa.com>
       cc:
       Subject:        Re: Re:[EE]: Light bulb make square to sine wave




You've been on this list for 9 years?  At this risk of dating myself, how
long has Microchip been around?  I always just assumed that they were a
newer company.  Man, I wish I was born 20 years earlier.  But I guess I
I'd be 20 years closer to death. hehehe

Thanks for the advice, much appreciated ... Peace

MJ Brush





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2004\05\17@113959 by David VanHorn

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At 10:20 AM 5/17/2004 -0500, llilespamspam_OUTSALTONUSA.COM wrote:

>Matthew,
>
>I believe Microchip was making the first PICs by that name in about 1989
>time period.  Not real sure. Someone else on the list will probably soon
>post with exact figures on these items, these are all from my (leaky)
>memory.
>
>Some time before that they were a division of another company, and the PIC
>architecture had been settled on in the late '70's or early '80's.   I
>started messing around with them in 1991-1993, IIRC, and soon my hobby
>turned into a job.

General Instruments, I thought.

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2004\05\17@140815 by llile

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This is definitely typical PIClist fare.

All of us are caught in the SMT/Thru hole gap.  Most good manufacturers
still make DIP parts for the developer, but there are many exceptions. And
thru-hole is not dead yet, my company still makes millions upon millions
of appliances 100% thru-hole.  Many of them are made by the crudest
possible process, hand stuffed and dip-soldered in a big solder pot,
cleaning consists of slushing in a bucket of solvent with a cooking spoon
and labor costs $10 a day.  I kid you not.  Simple boards are still
cheaper to make with thru-hole, require less skill on the part of the
operators, and can change production from one product to another with
virtually no delay.  They can literally build product A and the very next
board coming down the line is Product B without any delay for tooling
changes.  Forget that kind of flexibility with SMT.

Thru hole is also used in small production runs, where tooling costs are a
signifigant fraction of the production costs.  If you need ten of
something, SMT is nuts.

Many boards are still hybrids, with power filtering capacitors, relays,
and other heavy power comonents being thru-hole, microcontrollers being
SMT.

Anything slightly more sophisticated than a toaster, with size or power
restrictions, with tricky or sensitive electronics, or with high volumes,
or manufacturing in Europe or the USA, is likely to be better made SMT
these days.   I am willing to bet the first prototype was thru-hole in
most cases.

I've made many SMT prototypes by hand (a tedious process) but usually that
is very late in the design cycle.  Some PIClisters are going to SMT for
early prototypes, but I doubt it is a majority, it is just too inflexible.


There are a lot of places that make sheets of SMT/DIP adapters for various
package sizes for not a lot of money.  You snap off the adapter you need
and add a 0.100" header, voila - a thru hole part.

Big corporations aren't the only ones with access to SMT.  A lot of
electronics are designed by essentially one-man shops.  Sure it takes
money to make an SMT prototype, that is what clients are for!  If you have
400 smackers to invest in 10 or 20 boards at Advanced Circuits, then you
are in the SMT business.

-- Lawrence Lile





"Matthew Brush" <@spam@matthewbrushKILLspamspamyahoo.ca>
05/17/2004 10:49 AM


       To:     <KILLspamllileKILLspamspamsaltonusa.com>
       cc:
       Subject:        Re: Re:[EE]: Light bulb make square to sine wave


Hehe ... that's exactly what I was thinking about when I mentionned
wanting to be born 20 years ago, it seemed like you could make a tonne of
cash for the most trivial software/devices, but then again, I guess it
wasn't trivial back then.

The problem with today's technology is that all the parts are going to
surface mount, which means bye-bye solderless breadboard and hello PCB
production for every prototype.  It's really a bummer IMHO, cuz it's
taking a lot of resources away from the very people that tend to be the
most inventive.  Personally, I can't afford to buy SIP adapters or make
PCBs whenever I want to prototype a new circuit, so I just avoid SMT parts
altogether, but it's getting tougher.

Although I do like the fact that devices are getting smaller, I don't like
the fact that the only one's who will have access to technology will be
the big huge corporations.  Or at least it's heading that way i think.


P.S. I replied directly to you again, because I wasn't sure if the topic
was appropriate to send to the list.


MJ Brush
----- Original Message -----
From: RemoveMEllileTakeThisOuTspamsaltonusa.com
To: Matthew Brush
Cc: spamBeGonepiclistspamBeGonespammitvma.mit.edu
Sent: Monday, May 17, 2004 11:20 AM
Subject: Re: Re:[EE]: Light bulb make square to sine wave








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2004\05\17@201250 by Russell McMahon

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> 1. Notice that I put a topic tag [EE]: in the subject of the email.

But it should have been [EE:]     :-)
Colon is meant to be inside bracket.
Holy war ensues ....

>  These wierd tags are used by some PIClisters to sort out some of the
noise on
> the PIClist.

True. But they are used by ALL PICListers who want most people to see their
messages.
If you use no tag then only people who accept all mail (as I do) will see
them. People who have settings set to accept eg only [PIC:] and [EE:] will
not see untagged messages.
(Or, at least, that's what they tell me. As i see them all I can't be sure
this is actually true).


       Russell McMahon

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2004\05\18@042956 by Alan B. Pearce

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Well I will try and stick with the spirit of subject lines :))

>Many of them are made by the crudest possible process, hand
>stuffed and dip-soldered in a big solder pot, cleaning
>consists of slushing in a bucket of solvent with a cooking
>spoon and labor costs $10 a day.

Just dismantled an Akai video recorder that was beyond economic repair, and
am amazed at the PCB technology therein. Single sided phenolic board, with
SMD components on one side, and gazillions of wire links. Any electrolytic
appears to be a leaded component, no smd electros anywhere. Assembled in
Indonesia, for the UK market.

Still, it looks like I will get a few crystals and resonators for projects
from it. cannot work out who makes the IR receiver though, it has only what
looks like a date code on it.

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2004\05\18@171031 by michael brown

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From: <TakeThisOuTllileEraseMEspamspam_OUTSALTONUSA.COM>

<snip>
> 4. As stated on the PIClist.com home page, posts about religion or
> politics are discouraged, since there is no settling such questions.
We
> usually bend these rules in the wake of signifigant holidays or
gigantic
> international disasters, but only for a day or two and then James will
sit
> on us and make us talk about electronics again.

One thing you missed.  Never, never, never ask if .999999(repeating) is
exactly equal to 1.  I think this may be covered by the no religious
discussions rule.  ;-)

michael brown

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2004\05\18@174632 by llile

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>One thing you missed.  Never, never, never ask if .999999(repeating) is
exactly equal to 1.  I think this may be covered by the no religious
discussions rule.  ;-)

>michael brown

Well....   is it?
;-) ;-)

-- Lawrence Lile





michael brown <RemoveMEspam-mespamTakeThisOuTHOUSTON.RR.COM>
Sent by: pic microcontroller discussion list <PICLISTEraseMEspam.....MITVMA.MIT.EDU>
05/18/2004 08:05 AM
Please respond to pic microcontroller discussion list


       To:     EraseMEPICLISTspamMITVMA.MIT.EDU
       cc:
       Subject:        Re: [EE]: Light bulb make square to sine wave


From: <RemoveMEllileEraseMEspamEraseMESALTONUSA.COM>

<snip>
> 4. As stated on the PIClist.com home page, posts about religion or
> politics are discouraged, since there is no settling such questions.
We
> usually bend these rules in the wake of signifigant holidays or
gigantic
> international disasters, but only for a day or two and then James will
sit
> on us and make us talk about electronics again.

One thing you missed.  Never, never, never ask if .999999(repeating) is
exactly equal to 1.  I think this may be covered by the no religious
discussions rule.  ;-)

michael brown

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2004\05\18@221922 by michael brown

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From: <RemoveMEllilespam_OUTspamKILLspamSALTONUSA.COM>


> >One thing you missed.  Never, never, never ask if .999999(repeating)
is
> exactly equal to 1.  I think this may be covered by the no religious
> discussions rule.  ;-)
>
> >michael brown
>
> Well....   is it?
> ;-) ;-)

I think you should check the archives.  It should only take a month or
two to read the whole thread.
;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-) ;-)

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2004\05\18@222546 by Liam O'Hagan

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An old proof of this from high school...

X = 0.99999999 (repeating ad inifinitum)

10x = 9.999999999999 repeating

10x - x = 9x = 9.9999999 - .999999 = 9

9x = 9

X = 1


{Original Message removed}

2004\05\18@224702 by Jason S

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Nicely done, I've never seen it proven that way.

I just use the formula for sum of an infinite geometric series:
S = a / (1 - r)
where S is the sum, a is the starting term and r is the common ratio
here, S = 0.9 + 0.09 + 0.009 + 0.0009 ...  so a = 0.9 and r = 0.1 (each term
is 1/10th of the term before it).
now,
0.9999.... =  S = 0.9 / (1 - 0.1) = 0.9/0.9 = 1
So 0.9999...  = 1.

Also we should note, since 0.9999... is repeating, it is rational so it can
by definition be expressed as a quotient of integers.  In this case, that's
simply 1/1.

Jason



{Original Message removed}

2004\05\19@012657 by Wouter van Ooijen

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> > One thing you missed.  Never, never, never ask if
> > .999999(repeating) is
> > exactly equal to 1.  I think this may be covered by
> > the no religious discussions rule.  ;-)
>
> Well....   is it?

Covered by the 'no religious discussion rule'? Of course! :)

Wouter van Ooijen

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