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'PIC question'
1997\01\29@115116 by D. R. Chicotel

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I have a PIC that is producing a serial data stream that I want to
superimpose on a constant DC source such that a 0 bit is 12V and a 1 bit is
17V.  The DC source is provided by a LM338 which is a three pin adjustable
voltage regulator.  I want to connect an output pin from the PIC to the
reference pin on the LM338 in some way, but I have no idea what would be the
correct way to do this.

A related question:

How would you extract the logic level voltage from this DC source just
described so that another PIC could read the data stream?  A zener diode maybe?

I am trying to provide power to a motor and serial commands to a PIC using
the same two
wires.  The PIC would sit between the motor and the power and issue the
appropriate PWM signals to the motor as directed by the data stream.

Does anyone have any ideas please?

Thanks - DRC

1997\01\29@121957 by Jeff King

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At 10:19 AM 1/29/97 -0600, D. R. Chicotel wrote:

>A related question:
>
>How would you extract the logic level voltage from this DC source just
>described so that another PIC could read the data stream?  A zener diode maybe?

I'd used windowed comparator with some hysteresis. Lets say 12-13.5 is a one
and a 15.5-17 is a zero. 13.51-15.49 is in determinant. This might give you
some noise margin.

{Quote hidden}

My concern would be noise appearing on the data lines. Any type of
filtering to tame it would have the effect of reducing your data rate.
You'd also need to consider the effect of the higher logic level on
the speed of the motor and/or its affect on the type of regulator you
chose. Might not be a (much of) issue with linear regulator but could
cause you some problems with a buck regulator.

Good luck.

Regards,

------------------------------------
| Jeff King      Aero Data Systems |
| spam_OUTjeffTakeThisOuTspammich.com  P.O. Box 9325     |
| (810)471-1787  Livonia, MI 48151 |
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------------------------------------

1997\01\29@125441 by Martin McCormick

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In message <.....199701291619.KAA07644KILLspamspam@spam@houinet1.hou.moc.com>, "D. R. Chicotel" write
s:
>I have a PIC that is producing a serial data stream that I want to
>superimpose on a constant DC source such that a 0 bit is 12V and a 1 bit is
>17V.  The DC source is provided by a LM338 which is a three pin adjustable
>voltage regulator.

       The LM338 adjust pin is a good place to start.  The usual
configuration is to have a resistor leading from the adjust pin to ground.
The value will be somewhere in the 2-5 K-ohm range to allow you to get 12
Volts out.  There is also a 250-ohm resistor which acts as a feedback from
the regulated output (case) to Adjust.

If you are feeding more than 17 volts in to the un-regulated side of the
LM338, you can put a fixed resistor between Adjust and ground to set 17
Volts.  Call this R1.  Take a second resistor which we will call R2 and
choose its value so that when paralleled with R1 the output of the 338 drops
to 12 Volts.  This is your modulation input.  Instead of grounding R2,
connect it to the open-collector (or drain) output of the PIC.

       In the high state, R2 just won't be there and the output should be
17 Volts.  In the low state, R2 is paralleled with R1 and should give you
12 Volts.

       The LM338 has some protection circuits which are supposed to detect
thermal and over-current overloads so I don't know how fast you can modulate
without causing strange things to start happening.  I don't even know if
it is an issue, but keep it in mind.  Also, if the PIC output can not handle
the current or voltage involved, one might need to add a transistor and
connect R2 to the collector of that instead of directly to the PIC.


>  I want to connect an output pin from the PIC to the
>reference pin on the LM338 in some way, but I have no idea what would be the
>correct way to do this.
>
>A related question:
>
>How would you extract the logic level voltage from this DC source just
>described so that another PIC could read the data stream?  A zener diode maybe

       That should work or a 15-Volt reference which would be fed
in to one input of a comparator and provide a threshold for when the data
came across.  The LM339 quad comparator gives you open-collector outputs,
but would work nicely for this task.  I do not know how fast the 339 can
respond so you might want to be sure that it can handle the data rate.

Martin McCormick WB5AGZ  Stillwater, OK 36.7N97.4W
OSU Center for Computing and Information Services Data Communications Group

1997\01\29@132559 by D. R. Chicotel

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At 11:51 AM 1/29/97 -0600, you wrote:
{Quote hidden}

If I understand you:



                        >---------.------------> Gnd
                      /           |
PIC -----------------| NPN         R1
                      \           |
                        --- R2 ---.------------> LM338 adjust
                                  |
                               250 ohm
                                  |
                                  .------------> LM338 out


Right?   (Sorry for the crudeness of ASCII)

1997\01\29@134234 by John Dammeyer

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At 10:19 AM 29/01/1997 -0600, you wrote:
{Quote hidden}

At the receiving end regulate your supply voltage down to 5 volts for the
PIC power supply.  Be sure to include a blocking diode to prevent reverse
polarity.  On the supply side, before the blocking diode build a simple
voltage divider to bring your 12 and 17 volts down to two values between 0
and five volts;  not really important what the values are.  Use an LM339
comparitor to differentiate between the two values and produce a TTL output.
Your biggest problem is going to be filtering out the EMI from your motor
hence the diode.  You may even need some LC filtering after the diode to
keep spikes from giving you false start bits.

Good luck

John
Pioneers are the ones, face down in the mud,
with arrows in their backs.
Automation Artisans Inc.      Ph. 1-250-544-4950
PO Box 20002                  Fax 1-250-544-4954
Sidney, BC CANADA V8L 5C9

1997\01\29@134818 by optoeng

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Martin McCormick wrote:
>
> In message <.....199701291619.KAA07644KILLspamspam.....houinet1.hou.moc.com>, "D. R. Chicotel"
write
> s:
> >I have a PIC that is producing a serial data stream that I want to
> >superimpose on a constant DC source such that a 0 bit is 12V and a 1 bit is
> >17V.  .....<snip good answer to LM338 question>

> >How would you extract the logic level voltage from this DC source just
> >described so that another PIC could read the data stream? .....


Have a look at the PIC16C62X chips with integral comparators, at least,
if you have a few port bits to spare.

--
NOTE: remove asterisks from email address to reply directly

Paul Mathews, consulting engineer
AEngineering Co.

email: EraseMEoptoengspam_OUTspamTakeThisOuTwhidbey.com
non-contact sensing and optoelectronics specialists

1997\01\29@151704 by John Dammeyer

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At 11:51 AM 29/01/1997 -0600, you wrote:
>        That should work or a 15-Volt reference which would be fed
>in to one input of a comparator and provide a threshold for when the data
>came across.  The LM339 quad comparator gives you open-collector outputs,
>but would work nicely for this task.  I do not know how fast the 339 can
>respond so you might want to be sure that it can handle the data rate.
>
>Martin McCormick WB5AGZ  Stillwater, OK 36.7N97.4W
>OSU Center for Computing and Information Services Data Communications Group
>

Granted this is anecdotal but I use an LM339 as the chopper oscillator for a
chopped DC motor controller and 25Khz is no problem.

I doubt you will be able to modulate the 12 to 17 volt line any faster than
that.  Keep us informed as to how well it works

John
Pioneers are the ones, face down in the mud,
with arrows in their backs.
Automation Artisans Inc.      Ph. 1-250-544-4950
PO Box 20002                  Fax 1-250-544-4954
Sidney, BC CANADA V8L 5C9

1997\01\29@181351 by Tony Matthews

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D. R. Chicotel wrote:
>
> I have a PIC that is producing a serial data stream that I want to
> superimpose on a constant DC source such that a 0 bit is 12V and a 1 bit is
> 17V.  The DC source is provided by a LM338 which is a three pin adjustable
> voltage regulator.  I want to connect an output pin from the PIC to the
> reference pin on the LM338 in some way, but I have no idea what would be the
> correct way to do this.
>
> A related question:
>
> How would you extract the logic level voltage from this DC source just
> described so that another PIC could read the data stream?  A zener diode
maybe?
>
> I am trying to provide power to a motor and serial commands to a PIC using
> the same two
> wires.  The PIC would sit between the motor and the power and issue the
> appropriate PWM signals to the motor as directed by the data stream.
>
> Does anyone have any ideas please?
>
> Thanks - DRC
You could clean up the edges of your signal if you use a shcmitt trigger
opamp configuration.Or consider impressing a frequency shift key signal
on the 12v line.If you use a voltage divider on lm338 simply pull it up
with a diode from the pic output. my 2 cents. Tony M.

1997\01\31@015613 by nigelg

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In message  <PICLIST%97012912544183spamspam_OUTMITVMA.MIT.EDU> @spam@PICLISTKILLspamspamMITVMA.MIT.EDU
writes:


>         The LM338 has some protection circuits which are supposed to detect
> thermal and over-current overloads so I don't know how fast you can modulate
> without causing strange things to start happening.  I don't even know if
> it is an issue, but keep it in mind.  Also, if the PIC output can not handle
> the current or voltage involved, one might need to add a transistor and
> connect R2 to the collector of that instead of directly to the PIC.

The LM338 is commonly used in satellite receivers for feeding either 13 or 17
volts to the LNB - it can also have a 22KHz ripple imposed on it for switching
Universal LNB's. However, the 22KHz ripple is only a very low level, but it
should be worth a try!.

If you want to see the sort of circuit used, there is a diagram on my web site,
available as a HP printer dump and a PCX file (thank you David Tait!).

Nigel.

       /--------------------------------------------------------------\
       | Nigel Goodwin   | Internet : KILLspamnigelgKILLspamspamlpilsley.demon.co.uk     |
       | Lower Pilsley   | Web Page : http://www.lpilsley.demon.co.uk |
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'pic question'
1997\03\09@014544 by mail12706
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> Meyer's Patent really has nothing to do with the gas, since it is not
> Brown's Gas.  Try Brown's patents.  In addition, the method of
> accelerating Brown's Gas output is outlined in the Puharich patent NOT
> the Meyer patent, nor any of the Meyer patents. Actually, Meyer
> highlights the wrong principles, sorry.

1997\03\09@032927 by mail12706

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seriously, in addition, the Brown patent without actually mentioning it,
makes use of ORMEes in the form of Fe and Ni, which through the
electrolysis and the alkali metal hydroxide are placed in the high spin
state. Meyer never mentions the cruciality of using alkali metal
hydroxide and thereby excludes the need for Monatomic Material in the
splitter, and thereby skips the concept of a monatomic gas burning
(atomic heat providing) flame. Single atoms in an evenly balanced s-ORME
group provide a better electrode. Go read the Hudson Patent GB2219995
before you read up on electrolysis using ordinary T-metals.

Anyway, we are not here to speculate, that time is Over, and now we are
dealing with refining a finished product.  Speculaters should leave this
group and do their homework or either wait till the finished plans have
been posted on John Bedini's Tesla Switch page. Those who are willing to
take the problem of frequency generation at face value are those who
should reply.

This thing being already done, a single chip driver needs to be made at
the exact Puharich specified freq of 63.25khz on the msb of the nibble
counter, and 1/2,/1/4,1/8 summed up by four resistors on four pins
RB(0-3) to generate a single wire having the prescribed Puharich
frequencies.  There is no problem doing that.  The next problem is to
place the driver for the Tesla Switch as a decrement or subtract by R
routine in the same increment loop as the Puharich loop, and take the
output of that when it has count down to zero and toggle Tesla switch
pin RB(4) and complement RB(5).  Now RB(6) and RB(7) are inputs for two
pushbuttons which channel a bounceless switch routine that changes a
number R up or down, that number is the one that the one that should be
used by decrement or subtract routine above!  In this way, the Tesla
Switch frequency can be variable, while the Puharich switch is fixed.

Why am I integrating a Tesla Switch with a water splitter?  To ease up
on the battery, since most invariably, a battery will be used.  I am
sure you would do the same.

1997\03\10@235908 by tjaart

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mail12706@pop.net wrote:
>
> Subject: Message not deliverable
> Date: Sat, 8 Mar 1997 23:13:22 -0700
> From: RemoveMEHub.AdminKILLspamspamccmail.microchip.com (Administrator)
> To: "mail12706STOPspamspamspam_OUTpop.net" <spamBeGonemail12706STOPspamspamEraseMEPOP.NET>
>
> > Meyer's Patent really has nothing to do with the gas, since it is not
> > Brown's Gas.  Try Brown's patents.  In addition, the method of
> > accelerating Brown's Gas output is outlined in the Puharich patent NOT
> > the Meyer patent, nor any of the Meyer patents. Actually, Meyer
> > highlights the wrong principles, sorry.

Is the PIClist the correct formu to discuss people's gas problems ? <G>
Perhaps it should move to a medical forum?

--
Friendly Regards

Tjaart van der Walt
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