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help!-electrical noise problem — Parallax Forums

help!-electrical noise problem

ArchiverArchiver Posts: 46,084
edited 2002-05-28 17:15 in General Discussion
i've been using the BASIC stamp 2 for a robotic sculpture. the stamp
is controlling a 12v dc gear motor, and a radio shack sampler which i
modified so that it's triggered by a relay. my program for the stamp
is working fine (i tested it with LEDs) but the sampler is being
triggered when i don't want it to be. i was told that this is
interference of electrical noise from the motor...any suggestions on
how to get around this problem?
dianefig@yah

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2002-05-28 16:17
    --- In basicstamps@y..., "dianefig" <dianefig@y...> wrote:
    > i've been using the BASIC stamp 2 for a robotic sculpture. the
    stamp
    > is controlling a 12v dc gear motor, and a radio shack sampler which
    i
    > modified so that it's triggered by a relay. my program for the
    stamp
    > is working fine (i tested it with LEDs) but the sampler is being
    > triggered when i don't want it to be. i was told that this is
    > interference of electrical noise from the motor...any suggestions
    on
    > how to get around this problem?
    > dianefig@yah

    Hi,

    electrical noise can be tricky. There are two types in general. One
    type is radiated noise, which can be fixed by either moving the
    sampler a distance away from your motor and shielding the sampler
    with an aluminum or metal box. The other type is conducted, this
    noise which is conducted through the wires connecting to your sampler.
    Using shielded wires will help but it is best resolved with an
    electronic filter comprised of caps and inductor feeding the power
    source to the sampler. It would help if you could use a scope to see
    the noise level and frequency range. However you can try the following
    just to see if it solves the problem:

    <--- 100 mH ----> power source to sampler

    | |
    - 1 uf cap - 1 uf cap
    - -
    | |
    <
    > gnd
  • ArchiverArchiver Posts: 46,084
    edited 2002-05-28 16:36
    Hi,
    I am not quite sure what a radio shack sampler is or how your robotic sculpture
    is set up but I know in rc cars most motors have a small value capacitor (.1 uf
    or so) directly across their terminals to reduce spurious emissions. You can
    also put a small capacitor (100pf) across the positve and negative terminals
    wherever you have an ic: say for instance your stamp. It should be fine if you
    leave it on the board of education because it is already properly bypassed but
    if you have taken the stamp out and placed it into a breadboard you might want
    to bypass it with the small capacitors. The other problem could be lead lengths,
    if your board is 'sloppily' put together ie. 1 foot jumper cables connecting ic
    pins this could also result in noise. I hope this at least gets you started on
    something!
    Have a good day!
    -Randy Knutson

    dianefig <dianefig@y...> wrote: i've been using the BASIC stamp 2 for a
    robotic sculpture. the stamp
    is controlling a 12v dc gear motor, and a radio shack sampler which i
    modified so that it's triggered by a relay. my program for the stamp
    is working fine (i tested it with LEDs) but the sampler is being
    triggered when i don't want it to be. i was told that this is
    interference of electrical noise from the motor...any suggestions on
    how to get around this problem?
    dianefig@yah


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  • ArchiverArchiver Posts: 46,084
    edited 2002-05-28 17:15
    What kind of motor is it? how are you driving it? is there a schematic? Are the
    trigger wires in close proximity to the motor?

    dianefig <dianefig@y...> wrote: i've been using the BASIC stamp 2 for a
    robotic sculpture. the stamp
    is controlling a 12v dc gear motor, and a radio shack sampler which i
    modified so that it's triggered by a relay. my program for the stamp
    is working fine (i tested it with LEDs) but the sampler is being
    triggered when i don't want it to be. i was told that this is
    interference of electrical noise from the motor...any suggestions on
    how to get around this problem?
    dianefig@yah


    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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    Yahoo! - Official partner of 2002 FIFA World Cup

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  • ArchiverArchiver Posts: 46,084
    edited 2002-05-28 17:15
    What kind of motor is it? how are you driving it? is there a schematic? Are the
    trigger wires in close proximity to the motor?

    dianefig <dianefig@y...> wrote: i've been using the BASIC stamp 2 for a
    robotic sculpture. the stamp
    is controlling a 12v dc gear motor, and a radio shack sampler which i
    modified so that it's triggered by a relay. my program for the stamp
    is working fine (i tested it with LEDs) but the sampler is being
    triggered when i don't want it to be. i was told that this is
    interference of electrical noise from the motor...any suggestions on
    how to get around this problem?
    dianefig@yah


    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!?
    Yahoo! - Official partner of 2002 FIFA World Cup

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