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Thanks Sid (and how many feet? )Two different excel files, ... — Parallax Forums

Thanks Sid (and how many feet? )Two different excel files, ...

ArchiverArchiver Posts: 46,084
edited 2004-06-04 01:23 in General Discussion
In a message dated 6/2/2004 5:42:52 PM Eastern Daylight Time,
joeterk1@y... writes:


> Thanks Sid, and do you know how many
> feet of wire is the maximun for
> connect one pin of the BasicStamp A, to the other
> pin of the BasicStamp B ?
>
>

That would be for the serout? I would think that with 20 ga stranded you
could run 100 feet. 20 ga. has a resistance of about 1.2 ohms per hundred feet.
This would give you about a 1 volt drop over the distance, which should
leave enough to communicate with Stamp 2. I'd try it with 18 ga. lamp cord for a
start, although that may be a bit of over kill. If it was me I'd go with the
18 ga.

Sid


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

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-06-02 19:04
    In a message dated 6/2/2004 5:42:52 PM Eastern Daylight Time,
    joeterk1@y... writes:


    > Thanks Sid, and do you know how many
    > feet of wire is the maximun for
    > connect one pin of the BasicStamp A, to the other
    > pin of the BasicStamp B ?
    >

    Don't forget that you'll need a ground wire between the two Stamps. That's
    why I'd go with 18 ga. lamp cord, or maybe speaker w1re from Radio Shack.

    Sid


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2004-06-02 23:09
    Wow, 100 feet? I thought RS-232, with its
    +- 12 volt signaling, was only good to 50 feet
    (at 9600 baud).

    If you do this, you might want to talk at a
    lower baud-rate -- say 1200, or 300 baud. The
    problem here is not the resistance of the wire,
    the problem is the capacitance of driving that
    long a line. It could work -- the BS2 has
    LOTS of drive current (20 mA) available. The
    capacitance tends to remove the higher frequency
    parts of the signal -- your nice square wave
    232 signal starts looking like a rounded-hill
    sine wave.

    --- In basicstamps@yahoogroups.com, Newzed@a... wrote:
    > In a message dated 6/2/2004 5:42:52 PM Eastern Daylight Time,
    > joeterk1@y... writes:
    >
    >
    > > Thanks Sid, and do you know how many
    > > feet of wire is the maximun for
    > > connect one pin of the BasicStamp A, to the other
    > > pin of the BasicStamp B ?
    > >
    > >
    >
    > That would be for the serout? I would think that with 20 ga
    stranded you
    > could run 100 feet. 20 ga. has a resistance of about 1.2 ohms per
    hundred feet.
    > This would give you about a 1 volt drop over the distance, which
    should
    > leave enough to communicate with Stamp 2. I'd try it with 18 ga.
    lamp cord for a
    > start, although that may be a bit of over kill. If it was me I'd
    go with the
    > 18 ga.
    >
    > Sid
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2004-06-02 23:43
    I don't think it's the loss due to resistance so much as it is
    high-frequency roll-off due to the cable acting like a big capacitor and
    creating a low-pass filter. Note that with low-capacitance shielded wire you
    can run digital signals much further. I used to push 9600 baud RS-232 in
    excess of 300 feet with the right cable.

    Mike Sokol
    mike@f...
    www.fitsandstarts.com

    " One should not increase, beyond what is necessary,
    the number of entities required to explain anything"...
    -William of Occam-


    Original Message
    From: <Newzed@a...>
    To: <basicstamps@yahoogroups.com>
    Sent: Wednesday, June 02, 2004 5:56 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Thanks Sid (and how many feet? )Two different
    excel files, ...


    > In a message dated 6/2/2004 5:42:52 PM Eastern Daylight Time,
    > joeterk1@y... writes:
    >
    >
    > > Thanks Sid, and do you know how many
    > > feet of wire is the maximun for
    > > connect one pin of the BasicStamp A, to the other
    > > pin of the BasicStamp B ?
    > >
    > >
    >
    > That would be for the serout? I would think that with 20 ga stranded you
    > could run 100 feet. 20 ga. has a resistance of about 1.2 ohms per hundred
    feet.
    > This would give you about a 1 volt drop over the distance, which should
    > leave enough to communicate with Stamp 2. I'd try it with 18 ga. lamp
    cord for a
    > start, although that may be a bit of over kill. If it was me I'd go with
    the
    > 18 ga.
    >
    > Sid
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
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    >
    >
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    >
  • ArchiverArchiver Posts: 46,084
    edited 2004-06-04 01:23
    At >50 feet, I would start thinking wireless.

    My .02,

    Dennis

    Original Message
    From: Allan Lane [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=hzhKN1x5KioQ-2eAv-L5EGbl3217D_jaBhgR6dItPE-Q7kf3oWRXwgc9VqlaWuwYN7SMVxrtZANMbvgzIgRGqzp5]allan.lane@h...[/url
    Sent: Wednesday, June 02, 2004 3:09 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Thanks Sid (and how many feet? )Two different
    excel files, ...


    Wow, 100 feet? I thought RS-232, with its
    +- 12 volt signaling, was only good to 50 feet
    (at 9600 baud).

    If you do this, you might want to talk at a
    lower baud-rate -- say 1200, or 300 baud. The
    problem here is not the resistance of the wire,
    the problem is the capacitance of driving that
    long a line. It could work -- the BS2 has
    LOTS of drive current (20 mA) available. The
    capacitance tends to remove the higher frequency
    parts of the signal -- your nice square wave
    232 signal starts looking like a rounded-hill
    sine wave.
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