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Strange stuff — Parallax Forums

Strange stuff

ArchiverArchiver Posts: 46,084
edited 2003-11-29 00:39 in General Discussion
Hello everyone,

I have a Parallax BOE and am using it to control some servos
connected to the servo headers pins 14 and 15, but I am seeing some
strange things I can't explain. When I have a servo connected to pin
14 and do a looping pulsout to pin 15, the servo connected to 14
moves. Why is this? Here is my code:

main:

PULSOUT 15, 1000
PAUSE 20

GOTO main

Even if there is no servo connected to pin 15, the pin 14 servo still
moves very slowly. However if I add the following one line to the
program before the "main" routine this doesn't happen:

pulsout 14, anything

Why should I have to pre-pulse servo 14 to keep it from wandering
while pulsing servo 15? Please help.

-Nickel

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-11-28 18:38
    ive had the same problem with some robots too. I think its because the signal is
    "bleading" on to another pin. One way of fixing it is to set you pin to the
    servo you want to stay still to a low state. This should keep the servo from
    wandering:
    for example
    start:
    low 14
    pulsout 15,?????
    goto start
    of course when you want the servo to move again, well you know what to do. I
    hope this helps

    nickel152 <nickel152@y...> wrote:
    Hello everyone,

    I have a Parallax BOE and am using it to control some servos
    connected to the servo headers pins 14 and 15, but I am seeing some
    strange things I can't explain. When I have a servo connected to pin
    14 and do a looping pulsout to pin 15, the servo connected to 14
    moves. Why is this? Here is my code:

    main:

    PULSOUT 15, 1000
    PAUSE 20

    GOTO main

    Even if there is no servo connected to pin 15, the pin 14 servo still
    moves very slowly. However if I add the following one line to the
    program before the "main" routine this doesn't happen:

    pulsout 14, anything

    Why should I have to pre-pulse servo 14 to keep it from wandering
    while pulsing servo 15? Please help.

    -Nickel







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  • ArchiverArchiver Posts: 46,084
    edited 2003-11-29 00:39
    Thanks for the suggestion Walt. I'm glad I'm not the only one who has
    had this problem. More of a curious annoyance than a problem really.

    -Nickel


    --- In basicstamps@yahoogroups.com, Walt Trowbridge <wdt3_03@y...>
    wrote:
    > ive had the same problem with some robots too. I think its because
    the signal is "bleading" on to another pin. One way of fixing it is
    to set you pin to the servo you want to stay still to a low state.
    This should keep the servo from wandering:
    > for example
    > start:
    > low 14
    > pulsout 15,?????
    > goto start
    > of course when you want the servo to move again, well you know what
    to do. I hope this helps
    >
    > nickel152 <nickel152@y...> wrote:
    > Hello everyone,
    >
    > I have a Parallax BOE and am using it to control some servos
    > connected to the servo headers pins 14 and 15, but I am seeing some
    > strange things I can't explain. When I have a servo connected to
    pin
    > 14 and do a looping pulsout to pin 15, the servo connected to 14
    > moves. Why is this? Here is my code:
    >
    > main:
    >
    > PULSOUT 15, 1000
    > PAUSE 20
    >
    > GOTO main
    >
    > Even if there is no servo connected to pin 15, the pin 14 servo
    still
    > moves very slowly. However if I add the following one line to the
    > program before the "main" routine this doesn't happen:
    >
    > pulsout 14, anything
    >
    > Why should I have to pre-pulse servo 14 to keep it from wandering
    > while pulsing servo 15? Please help.
    >
    > -Nickel
    >
    >
    >
    >
    >
    >
    >
    > 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.
    >
    >
    > Your use of Yahoo! Groups is subject to
    http://docs.yahoo.com/info/terms/
    >
    >
    >
    >
    > Do you Yahoo!?
    > Free Pop-Up Blocker - Get it now
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
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