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Potentiometers — Parallax Forums

Potentiometers

ArchiverArchiver Posts: 46,084
edited 2003-09-09 04:28 in General Discussion
Hi all, Im new to the group so Im sorry if this topic has been
covered. Im trying to control serveral servos using a SSC2, driven by
a BS2, which is reading several potentiomers. Sounds straight forward
until I try to read from the pots. Im using the resistor/Cap method
in the BS manual, but arent havent any luck. Im getting a reading of
0 from the pot until I touch the pot then it goes beserk, when I turn
the pot I get no responce.
Am I better off using a BS1 and using the POT command ?. Is there an
IO expander for the BS1.

I'd really like to get the BS2 working as I've already bought it. Any
help would be greatly appreciated. Thanx in advance.

RXC

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-07-04 16:32
    The POT command has it's limitations. A better solution might be to use a
    serial ADC. Maxim makes excellent ones and stamp code for interfacing them
    is available. Check out the MAX187 and 186 at:

    http://www.maxim-ic.com

    These folks also have an outstanding free sample policy 8^]

    Best, Duncan
  • ArchiverArchiver Posts: 46,084
    edited 2000-07-05 03:14
    So if I go down the ADC path, is this going to take less effort than RCTime.
    Can anyone draw me a simple circuit to give me an idea on how to use a ADC
    in the circuit.

    Regards
    RXC

    Original Message
    From: orthner@s... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=LtnIZ-GSfBw7uIbcaND_8JnIx04nTomWE-ZmFI1nIrz0CxdUpc-JTufuexZlsenTMYLciwD83lLNpDWF3lnd]orthner@s...[/url
    Sent: Wednesday, 5 July 2000 3:32 a.m.
    To: basicstamps@egroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] Potentiometers



    The POT command has it's limitations. A better solution might be to use a
    serial ADC. Maxim makes excellent ones and stamp code for interfacing them
    is available. Check out the MAX187 and 186 at:

    http://www.maxim-ic.com

    These folks also have an outstanding free sample policy 8^]

    Best, Duncan
  • ArchiverArchiver Posts: 46,084
    edited 2000-07-05 08:06
    At 02:14 PM 7/5/00 +1200, you wrote:

    >So if I go down the ADC path, is this going to take less effort than RCTime.
    >Can anyone draw me a simple circuit to give me an idea on how to use a ADC
    >in the circuit.

    The hookup is simple and will be clearly shown in the datasheet for the
    device, which can be D/L'd from the Maxim site. The code is only a few
    lines - I can't say whether this is 'less effort' or not...For using pots
    to drive seros via pulsout I've always found RCtime to be inadequate - not
    enough resolution and too slow. But if it works for you - go with it 8^]

    Best, Duncan
  • ArchiverArchiver Posts: 46,084
    edited 2001-04-01 04:17
    I need to know how to hook up a potentiometer to my Basic Stamp2 and
    how to program it so it can read what it's set at.
    Thanks.
  • ArchiverArchiver Posts: 46,084
    edited 2001-04-01 04:18
    Mat I suggest that you do a search of this group first to see if the
    question has allready been answered, there are some good examples around,
    plus the RCTIME command as shown in the stamp manual is worth a look.
    Chris

    Original Message
    From: <sjohns10@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Sunday, April 01, 2001 11:17 AM
    Subject: [noparse][[/noparse]basicstamps] potentiometers


    > I need to know how to hook up a potentiometer to my Basic Stamp2 and
    > how to program it so it can read what it's set at.
    > Thanks.
    >
    >
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-04-01 04:23
    Go to the Parallax site and download the schematic and instructions for the
    Activity Board. It shows you how to hook up a pot and how to read it.

    Most of what I picked up on using my Basic Stamp has been scamming stuff off
    their web page. Lots of useful stuff there if you take time to poke through
    it.

    Original Message


    > I need to know how to hook up a potentiometer to my Basic Stamp2 and
    > how to program it so it can read what it's set at.
  • ArchiverArchiver Posts: 46,084
    edited 2001-04-01 12:06
    [font=arial,helvetica]In a message dated 3/31/01 11:44:12 PM Central Daylight Time,
    sjohns10@hotmail.com writes:


    I need to know how to hook up a potentiometer to my Basic Stamp2 and
    how to program it so it can read what it's set at



    Take a look at the description for RCTIME in the Stamp manual. ·In that
    section you will find the schematic for connecting a pot to the Stamp.

    [/font]
  • ArchiverArchiver Posts: 46,084
    edited 2003-09-08 01:57
    Hello, im having trouble finding a way to read the value of an
    analogue potentiometer, any suggestions? Thanks!
  • ArchiverArchiver Posts: 46,084
    edited 2003-09-08 05:37
    --- In basicstamps@yahoogroups.com, "blinkersrulez" <binky7000@a...>
    wrote:
    > Hello, im having trouble finding a way to read the value of an
    > analogue potentiometer, any suggestions? Thanks!


    Binky, Use a BS2 module at least, and look in the pbasic syntax guide
    under RCTIME command.

    Other documents you might like are available at www.parallax.com

    Regards,
    C.C.
  • ArchiverArchiver Posts: 46,084
    edited 2003-09-08 06:51
    --- In basicstamps@yahoogroups.com, "captainconstructor"
    <captainconstructor@y...> wrote:
    > --- In basicstamps@yahoogroups.com, "blinkersrulez" <binky7000@a...>
    > wrote:
    > > Hello, im having trouble finding a way to read the value of an
    > > analogue potentiometer, any suggestions? Thanks!
    >
    >
    > Binky, Use a BS2 module at least, and look in the pbasic syntax
    guide
    > under RCTIME command.
    >
    > Other documents you might like are available at www.parallax.com
    >
    > Regards,
    > C.C.

    When I try to use the RCTIME with my BS2sx all I get is either 1 or 0
    any ideas? Thanks for your help!
  • ArchiverArchiver Posts: 46,084
    edited 2003-09-09 02:49
    The Basic Stamp comes with some VERY fine manuals. They are not only
    available in hard-copy format, but they are also available online here:

    http://www.parallax.com/html_pages/downloads/basicstamps/documentation_basic_sta\
    mp.asp


    The reading of the value of a POT is a very good first project. I suggest
    you RTFM (Read The Fine Manual) and then, if you still have questions,
    post your code and results of your experiments, and I'm sure everyone
    will be happy to help you. Not trying to be obstinate, just trying to
    adhere to good proverbs:

    "Give a man a fish, and you feed him for a day. Teach a man to fish, and
    you feed him for life."

    or:

    "Build a man a fire, and he's warm for a day. Set a man on fire, and he's
    warm for the rest of his life." [noparse]:)[/noparse]

    Vern

    PS: Cant take credit for the above, got it from here:
    http://www.halfbakery.com/idea/Give_20A_20Man_20A_20Fish_2e_2e_2e

    --
    Vern Graner CNE/CNA/SSE | "If the network is down, then you're
    Senior Systems Engineer | obviously incompetent so why are we
    Texas Information Services | paying you? Of course, if the network
    vern@t... www.txis.com | is up, then we obviously don't need
    Cell 507-7851 Desk 328-8947 | you, so why are we paying you?" VLG



    blinkersrulez said:
    > Hello, im having trouble finding a way to read the value of an
    > analogue potentiometer, any suggestions? Thanks!
    >
    >
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  • ArchiverArchiver Posts: 46,084
    edited 2003-09-09 04:28
    --- In basicstamps@yahoogroups.com, "blinkersrulez" <binky7000@a...>
    wrote:

    > When I try to use the RCTIME with my BS2sx all I get is either 1 or
    0
    > any ideas? Thanks for your help!

    Can you post the relevant code and schematic?

    Without them...
    In no particular order...

    If you forgot to discharge the cap before issuing rctime you will get
    a 1 result...If your variable is bit-sized (should be word) you would
    only get a 0 or 1 result...the component selection/hook-up may not be
    correct.

    Jamie says "Hmm...could be anything!"

    C.C.
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