parasite power - steal power from data line

Archiver

I would like to use the Basic Stamp IIp to transmit data and power
to another BS IIp using two lines - one ground and one data/power.
I read a paper by Dan Awtrey of Dallas Semiconductor at
http://pdfserv.maxim-ic.com/en/an/onewirebus.pdf
that described how this could be done and I wanted to know if anyone
had any experience in this area.

Note that I don't have to use this specific method - I am just
looking for a means of transmitting data and power using just two
lines.


thanks

paul

Archiver

Devices that hang on a 1-Wire buss require very little current. I don't
think you're going to get away with sourcing current from a Stamp I/O
pin to another Stamp, especially if that other Stamp is driving any
other loads.

-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office

---

Original Message

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From: justforgoyourmove [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=GPjTj71FTCLmWUPVEaSLeNnGpSJUPQQpQAQcFp2ocwBmha38IEYKqaYvWsPbYNOEN9hXvkMRVWUPHA]pjw24@c...[/url
Sent: Wednesday, January 28, 2004 2:25 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] parasite power - steal power from data line


I would like to use the Basic Stamp IIp to transmit data and power
to another BS IIp using two lines - one ground and one data/power.
I read a paper by Dan Awtrey of Dallas Semiconductor at
http://pdfserv.maxim-ic.com/en/an/onewirebus.pdf
that described how this could be done and I wanted to know if anyone
had any experience in this area.

Note that I don't have to use this specific method - I am just
looking for a means of transmitting data and power using just two
lines.


thanks

paul

Archiver

As you dont have enough juice to feed the Stamps with, hve you thought of
adding some high frequency on top of the power signal ??

If you use DC, you can add some oscilating signals with the help of toroids,
and at the opposite side you would do the same for demodulation.

If you use AC to feed the remote Stamp, just transmit data on ever zero
crossing cycle. You are able to transmit a lot of data using this method.
Thats the one they use for the famouse X10.


Antonio Sergio Sena







> I would like to use the Basic Stamp IIp to transmit data and power
> to another BS IIp using two lines - one ground and one data/power.
> I read a paper by Dan Awtrey of Dallas Semiconductor at
> http://pdfserv.maxim-ic.com/en/an/onewirebus.pdf
> that described how this could be done and I wanted to know if anyone
> had any experience in this area.
>
> Note that I don't have to use this specific method - I am just
> looking for a means of transmitting data and power using just two
> lines.
>
>
> thanks
>
> paul
>
>
>

Archiver

If I were to attempt such a thing, and expected the slave stamp
to need much power I would probably try something like this:

First, buffer the output of the master stamp with an amplifier that
can source *plenty* of current, and maybe do it at a higher
voltage, like 8 or so. Send the data down the wire using this
high power output. At the receiving end, spilt the data line
and send it to a diode and large capacitor. (power for the slave)
and also through a resistor to the slave stamp I/O pin. Put a
zener diode across the slave I/O to keep from overstressing the
stamp.
Try and arrange your code so that during dead time when no data
is being transmitted, the stamp pin is high and feeding power
to the slave. If you use a high enough voltage you should be able
to use a regulator (and lots of capacitance) to get a nice clean
voltage for the slave stamp.


Steve

---

At 12:24 PM 1/28/2004, Paul wrote:

>I would like to use the Basic Stamp IIp to transmit data and power
>to another BS IIp using two lines - one ground and one data/power.
>I read a paper by Dan Awtrey of Dallas Semiconductor at
>http://pdfserv.maxim-ic.com/en/an/onewirebus.pdf
>that described how this could be done and I wanted to know if anyone
>had any experience in this area.
>
>Note that I don't have to use this specific method - I am just
>looking for a means of transmitting data and power using just two
>lines.
>
>
>thanks
>
>paul

---

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[noparse][[/noparse]Non-text portions of this message have been removed]

Archiver

When I've seen this sort of thing before,
typically the power supply line is put to
+5 volts (or perhaps 9 or 12 volts, if
you're driving for some distance) and the
data signal is then capacitively coupled
onto and off of the power line.

If you use 9 or 12 volts, the idea is
that you'll have a linear regulator
at the 'far end' to provide the
+5. With the Stamp, of course,
there's an on-module regulator, so
perhaps you don't need this part.

I don't think 'pure' RS-232 will
do this well -- you need a signal
with little DC component. You could
use 'SEROUT' to generate this if you
use "U" for a 0, and "f" for a 1.

The reason to use these two characters is
in binary "U" is 1010101 (hex 55), and
"f" is 110110 (hex 66) both of which
limit their DC component.


--- In basicstamps@yahoogroups.com, laurasdog@w... wrote:
> If I were to attempt such a thing, and expected the slave stamp
> to need much power I would probably try something like this:
>
> First, buffer the output of the master stamp with an amplifier that
> can source *plenty* of current, and maybe do it at a higher
> voltage, like 8 or so. Send the data down the wire using this
> high power output. At the receiving end, spilt the data line
> and send it to a diode and large capacitor. (power for the slave)
> and also through a resistor to the slave stamp I/O pin. Put a
> zener diode across the slave I/O to keep from overstressing the
> stamp.
> Try and arrange your code so that during dead time when no data
> is being transmitted, the stamp pin is high and feeding power
> to the slave. If you use a high enough voltage you should be able
> to use a regulator (and lots of capacitance) to get a nice clean
> voltage for the slave stamp.
>
>
> Steve
>
>

---

> At 12:24 PM 1/28/2004, Paul wrote:
>
> >I would like to use the Basic Stamp IIp to transmit data and power
> >to another BS IIp using two lines - one ground and one data/power.
> >I read a paper by Dan Awtrey of Dallas Semiconductor at
> >http://pdfserv.maxim-ic.com/en/an/onewirebus.pdf
> >that described how this could be done and I wanted to know if
anyone
> >had any experience in this area.
> >
> >Note that I don't have to use this specific method - I am just
> >looking for a means of transmitting data and power using just two
> >lines.
> >
> >
> >thanks
> >
> >paul
>
>

---

>
>
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.569 / Virus Database: 360 - Release Date: 1/26/2004
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]

Archiver

>I would like to use the Basic Stamp IIp to transmit data and power
>to another BS IIp using two lines - one ground and one data/power.
>I read a paper by Dan Awtrey of Dallas Semiconductor at
>http://pdfserv.maxim-ic.com/en/an/onewirebus.pdf
>that described how this could be done and I wanted to know if anyone
>had any experience in this area.
>
>Note that I don't have to use this specific method - I am just
>looking for a means of transmitting data and power using just two
>lines.
>
>
>thanks
>
>paul

Paul,
Here is a solution that I have used before that might work for
you. Basically you drive an H-Bridge in saturation mode (full
forward or full reverse) as if you were driving a motor from the
"Master Stamp". The polarity represents your data weather it's
a 1 or a 0. On the receiving "Slave Stamp" you have a full wave
bridge rectifier converting the AC (data signal) back into DC to
supply power on the receiving end. In addition you take a leader
line off of the AC so that the "Slave Stamp" can determine the
incoming polarity and reconstruct the original data.

http://www.angelfire.com/wizard/y2kbc/STAMPS/dop.gif

-Beau Schwabe

Archiver

Here is one possibility that my professor found:

http://www.hth.com/plm-24/

The plm-24 is described as perfect for working with BS's

Thanks

Paul
--- In basicstamps@yahoogroups.com, "justforgoyourmove" <pjw24@c...>
wrote:
> I would like to use the Basic Stamp IIp to transmit data and power
> to another BS IIp using two lines - one ground and one
data/power.
> I read a paper by Dan Awtrey of Dallas Semiconductor at
> http://pdfserv.maxim-ic.com/en/an/onewirebus.pdf
> that described how this could be done and I wanted to know if
anyone
> had any experience in this area.
>
> Note that I don't have to use this specific method - I am just
> looking for a means of transmitting data and power using just two
> lines.
>
>
> thanks
>
> paul