Re: 1-wire to USB converter that can use 1820s directly

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Robert L Bass" <sales@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:89qb429lpr5ka0deorbb2ogrfil4vbiqbg@xxxxxxxxxx

Dude,

You're all clearly unaware that we've received a personal visit from a
legendary internet personality, Rod Speed.

http://www.google.com/search?q=%22rod+Speed%22

When I mentioned "RS" to an Aussie mate of mine a few years back, I got the
whole scoop.  I'll add my limited wisdom inline:

>> Its clearly a lot cleaner to use one of the existing USB ports
>> than to need to add another PCI card to support serial ports.

"USB Only" is obviously a much higher priority requirement for the OP than
most replies have acknowledged.  If there's anything that's typical about
Usenet in this thread, it's that a lot of answers that fall under the
heading: "not *exactly* what that user wanted."  If my mate's read of Speed
is right, we can be sure, if nothing else, that RS knows *exactly* what he
wants.  That's probably pretty clear by now, anyway.

The state of PC and HA wiring is such that it's easy (for me at least, and
especially my wife) to
understand how someone could finally say "not one more f'ing wire!"  I, too,
am struggling with cleanly implementing similar systems and have no serial
ports to spare nor a desire to add additional ports via PCI cards.

> On one of my older machines we had need of eight serial ports for a bunch
of
> terminals and various other I/O devices.  I forget the brand (it was quite
a few
> years ago that I did this) but I installed a PCI card with an RS485 port.
To
> this I connected a port expander with 16 RS232 (convertible to RS485 but I
> didn't need that) ports.  The operating system was THEOS though the kit
came
> with a driver disk for Windows as well.

This sort of approach is fraught with peril, as the cliche goes.  You are
limited to what PC can talk to your net (got have a special board
installed), gotta learn another OS (Theos or some other proprietary OS).  A
machine failure is a crisis.  Rod obviously wants something he can maintain
easily.  Anything that requires a special board in a PC means "maintenance
issues" and I've supported enough of them to know.  USB-based means he can
plug it into a laptop, a Mac, a PDA and lots of other things and *hopefully*
run his sensor net without having to crack open a machine or buy cards or
adapters.  I can see why he's so hard over on demanding that as a
requirement.  It's incredibly important for CPU device "independence."

> The entire system was extremely simple to set up and use.  The hardware
ran 24/7
> for many years without a hitch.

Know why?  You probably never tinkered with it once it was set up and
running.  Those sorts of systems work fine once you've put in the time to
set them up.  But if they fail, you either need an identical spare or lots
of qualified spare parts to really assure 24/7 performance.  I think that's
one thing the OP, Mr. Speed, has in mind.

> We sold the business and the computer system
> with it six years ago.  To the best of my knowledge it's still
> running today.

Compaq, at its zenith, was selling wonderfully overbuilt machines with
connectors rated for 10X what was then "industry standard practice."  I
marvel at the sturdiness of some of the old PC "iron."  It doesn't, however,
have a whole lot to do with the OP's USB requirement.

> I wish I could say the same for some of my other PC equipment.

Still, performance doubles every few years so longevity isn't as big a
factor as it would be in a car.  I would love to see my gas mileage improve
the way PC clock speeds and peripheral throughput has.  I would buy a new
car as often as I bought a new PC if it did.  IMHO, longevity is not a big
requirement of the OP.  I would say his USB requirement is actually a way of
factoring in getting a new PC and being able to use it to control the net
right out of the box, without adding a serial IO card.

> > Serial ports done that way arent that easy to support in VBA
> > either, support for non standard serial ports is pretty poor.
>
> Anything is easy if you know how.  I don't write code . . .

You should have stopped right there.  I know how to rebuild a VW engine.
That doesn't make it easy in the slightest.  If you don't write code, it's
really a stretch criticize his code-writing ability.  I don't do much
programming, but I know that experience ranges wildly.  If he wants to stick
with standard, easy to understand and probably easy to port IO routines,
well, that's clearly his choice and one I would be likely to make as well.

The OP is really the only one capable of commenting on the mix of factors
that dictate his choice of SW.  He's reiterating how important "standard" is
to him in his design specs.  Still, you're not listening!!!

> but folks I work with develop software for industrial PC's
> and they don't seem to have much of a problem.  I'm not trying to
> belittle your skills, friend.

Perhaps you aren't, but I'm betting he'll take umbrage.  He's explained his
requirements to the point of perseveration. (-:  Disparaging his programming
skills, however "gently" isn't likely to get a positive response.  I'll bet
it contains the "F" word at least.

> But I think you're unnecessarily constricting your project
> by ignoring other possible solutions.

And he should care what you think about his project exactly why?  (-:

I don't want to sound mean, but I see so many newsgroups where the responses
just get farther and farther away from the specs that I feel I have entered
the twilight zone. I hear that "doo doo, doo doo" music right now.  He wants
a USB solution that he can program in VBA in a non-exotic sort of way.
Pretty simple. It may not be realistic, given some other constraints on the
project, but that's what I expect he came here to find out.  There have been
a number of posts that I think have been very helpful, but in the end, he's
the one who gets to decide if they were.

> FWIW, some of the alarm system configuration software I regularly use
requires a
> serial port and will not function at all using a USB-serial converter.

This is probably one of the many reasons the OP demands a straight up USB
solution.

> Some of the other software functions perfectly with either type.
> What I'm trying to say is that nothing is 100% better or worse.

Interestingly enough, from my read of your comment, you're *exactly* backing
up the OP's reasons for NOT wanting anything BUT a USB solution.  The more
intervening HW or SW objects, the more chance that one of them will not
function correctly.  The same is true for any non-standard SW treatment.

> On another note, I haven't followed this thread very closely so forgive me
if I
> got it wrong but did you indicate you plan to use telco cables (the flat
"satin"
> stuff) to wire up this system in multiple rooms?  If so, I'd strongly
advise you
> to reconsider.

This may indeed be an area where the OP should test assumptions before going
much further.  I suspect he may have already done the testing, but my
experience with cutting and soldering those cables has been bad.  Maybe
Ozian RJ11 cables are different or he's got a batch of cables he knows he
can work with.  I suspect by the time he gets this far down, you've already
lost much of your ability to persuade him.  :-)

> That's an area where I have extensive knowledge and hands-on
> experience.  You really don't want to try to use that kind of cable for
> permanent wiring of any sort.  More importantly, you don't want to run it
> through walls (code violation).  It's a royal PITO to splice, does not
take well
> to being stapled in place and is not robust enough for anything other than
it's
> intended purpose -- as a flexible cord to plug telephones into nearby wall
> jacks.
>
> If that is not your intention, ignore the above paragraph.  :^)

I hope he expands on the RJ11 cabling issue.  I can see why he wants to use
the cable - it's pretty unobtrusive as far as cables go, but it may be
harder to work with than he's expecting.  If he's got a solution to what I
have found were to be the most unsolderable wires on earth, I'd like to
learn it.

--
Bobby G.