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Sensor question — Parallax Forums

Sensor question

ArchiverArchiver Posts: 46,084
edited 2003-10-24 18:33 in General Discussion
To control the filling level of a sawdust bin I am looking for a sensor.
I heard people use a slowly turning motor with a paddle, I guess when it
stalls in the dust the current goes up and this signal can be processed
further.

Where do I find such a device. What type of motor can be used for this purpose
without burning it up in the process??

TIA

Uwe

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-10-23 22:22
    Try www.keyence.com



    To control the filling level of a sawdust bin I am looking for a sensor.
    I heard people use a slowly turning motor with a paddle, I guess when it
    stalls in the dust the current goes up and this signal can be processed
    further.

    Where do I find such a device. What type of motor can be used for this
    purpose without burning it up in the process??

    TIA


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-10-23 22:23
    Would ultrasonic work for this? Sawdust?? Hmmm....there'd have to be some
    sort of reflection off of this!

    Disect your bin with a long thin bar with the sensor in the middle and
    monitor your dump height....



    Original Message
    From: othello159 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=DrPB0T93NBe8KodUIg0pumhoWOd58yvvUq3_DRalUjcQ1GMaEy4oKDCdC9wRLLMMYHWC35Pusb77SjHYwQ]othello159@h...[/url
    Sent: October 23, 2003 1:46 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Sensor question


    To control the filling level of a sawdust bin I am looking for a sensor. I
    heard people use a slowly turning motor with a paddle, I guess when it
    stalls in the dust the current goes up and this signal can be processed
    further.

    Where do I find such a device. What type of motor can be used for this
    purpose without burning it up in the process??

    TIA

    Uwe


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  • ArchiverArchiver Posts: 46,084
    edited 2003-10-24 01:28
    I don't know, I would be afraid of false alarms. There is sawdust all over and I
    am interested in the particular moment where sawdust is not only all over but
    starts to pack. That is why the paddle motor seemed to make sense since I
    imagine it senses density and ignores light density dust.

    Uwe


    --- In basicstamps@yahoogroups.com, "Brady,Steven [noparse][[/noparse]PYR]" <steven.brady2@e...>
    wrote:
    > Would ultrasonic work for this? Sawdust?? Hmmm....there'd have to be some
    > sort of reflection off of this!
    >
    > Disect your bin with a long thin bar with the sensor in the middle and
    > monitor your dump height....
    >
    >
    >
    >
    Original Message
    > From: othello159 [noparse][[/noparse]mailto[noparse]:o[/noparse]thello159@h...]
    > Sent: October 23, 2003 1:46 PM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Sensor question
    >
    >
    > To control the filling level of a sawdust bin I am looking for a sensor. I
    > heard people use a slowly turning motor with a paddle, I guess when it
    > stalls in the dust the current goes up and this signal can be processed
    > further.
    >
    > Where do I find such a device. What type of motor can be used for this
    > purpose without burning it up in the process??
    >
    > TIA
    >
    > Uwe
    >
    >
    > 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/
  • ArchiverArchiver Posts: 46,084
    edited 2003-10-24 01:45
    If it is safe to assume that when the amount of sawdust approaches the
    "packed" state or gets to the packed state the mass (weight) will also be
    measureably more than unpacked. Parallax sells a force sensor called the
    flexiforce that
    is easy to use with the RCTIME command and may work well for your application.

    see http://www.parallax.com/detail.asp?product_id=30056

    ken

    ________________________________________________
    I don't know, I would be afraid of false alarms. There is sawdust all over
    and I am interested in the particular moment where sawdust is not only all over
    but starts to pack. That is why the paddle motor seemed to make sense since I
    imagine it senses density and ignores light density dust.


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-10-24 02:20
    If I remember correctly these devises are called Bindicators. Used in
    silos and holding bins they use shaded pole motors geared down to
    only 1 or 2 revolutions a minute. The shaft that rotates inside the
    silo is stopped when the level reaches the paddle attached to the
    shaft. The shaft continues to move adding torque to the shaft that is
    spring loaded when that torque overcomes the spring it trips a limit
    switch (micro switch) that also stops the motor.

    Jean-Louis




    othello159 wrote:

    >To control the filling level of a sawdust bin I am looking for a sensor.
    >I heard people use a slowly turning motor with a paddle, I guess when it
    stalls in the dust the current goes up and this signal can be processed
    further.
    >
    >Where do I find such a device. What type of motor can be used for this purpose
    without burning it up in the process??
    >
    >TIA
    >
    >Uwe
    >
    >
    >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/
    >
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-10-24 13:48
    Yes, thats what I thought too, but the range of weight of one full bin is still
    way too great to be used as an indicator.
    For there could be heavier kinds of wood chips, or wet wood chips and all of
    that throws this approach off.

    I searched around and found that this type of indicator is extensively used by
    silo people and they call it a rotary paddle bin monitor and god is it
    expensive. We are not talking a $2 chip, we are talking about a solidly built
    $200 + motor unit.

    Maybe for now I have to continue sticking my head in there for a visual check
    every now and then...

    Uwe




    --- In basicstamps@yahoogroups.com, smartdim@a... wrote:
    > If it is safe to assume that when the amount of sawdust approaches the
    > "packed" state or gets to the packed state the mass (weight) will also be
    > measureably more than unpacked. Parallax sells a force sensor called the
    flexiforce that
    > is easy to use with the RCTIME command and may work well for your application.
    >
    > see http://www.parallax.com/detail.asp?product_id=30056
    >
    > ken
    >
    > ________________________________________________
    > I don't know, I would be afraid of false alarms. There is sawdust all over
    > and I am interested in the particular moment where sawdust is not only all
    over
    > but starts to pack. That is why the paddle motor seemed to make sense since I
    > imagine it senses density and ignores light density dust.
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-10-24 13:57
    --- In basicstamps@yahoogroups.com, "othello159" <othello159@h...>
    wrote:
    > To control the filling level of a sawdust bin I am looking for a
    sensor.
    > I heard people use a slowly turning motor with a paddle, I guess
    when it stalls in the dust the current goes up and this signal can
    be processed further.
    >
    > Where do I find such a device. What type of motor can be used for
    this purpose without burning it up in the process??
    >
    > TIA
    >
    > Uwe



    Pretty much any DC motor could be used, just current limit the power
    to it and put a hall effect senosr on the shaft.

    a clutch would work too if the sensor was on the thing moving.

    either way, reverse the direction upon stopping to prevent some stray
    bunching from a flase alarm.

    and cut power shortly after a known stop.


    A sonic system would be 'heard' across the faling fill, but muffled
    when one side is packed, that is if you can locate the sensors under
    the upper limit.
  • ArchiverArchiver Posts: 46,084
    edited 2003-10-24 18:18
    This is an interesting link with the same question
    http://www.plctalk.net/qanda/arch/topic/121.html

    Oorspronkelijk bericht
    Van: othello159 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=45Fyp3IvbZWEk_YcL3EYSyOmmcbQ5M4KigNirUAcaXnN5ofbGyJxrdElSQUaB5o9Lrb-DPcnFAo82JThC8uW]othello159@h...[/url
    Verzonden: donderdag 23 oktober 2003 22:46
    Aan: basicstamps@yahoogroups.com
    Onderwerp: [noparse][[/noparse]basicstamps] Sensor question


    To control the filling level of a sawdust bin I am looking for a sensor.
    I heard people use a slowly turning motor with a paddle, I guess when it
    stalls in the dust the current goes up and this signal can be processed
    further.

    Where do I find such a device. What type of motor can be used for this
    purpose without burning it up in the process??

    TIA

    Uwe


    To UNSUBSCRIBE, just send mail to:
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  • ArchiverArchiver Posts: 46,084
    edited 2003-10-24 18:33
    What about an IR tree?

    Sorry if I'm repeating ideas...haven't gone through the entire thread yet.

    But have a number of IR Tx'ers along one side and Rx'ers on the other side.
    This would give you a resolution to at least know when you are getting close
    to filling your tank....

    Original Message
    From: othello159 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=gQJJpz73g-nSeLledK3f7Z8xMn3YilvCk7PzRyzOtjEWBLyJkZmx8xxu301NaHmdIghd34gfJ5AeAGf-]othello159@h...[/url
    Sent: October 24, 2003 05:48
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Sensor question


    Yes, thats what I thought too, but the range of weight of one full bin is
    still way too great to be used as an indicator. For there could be heavier
    kinds of wood chips, or wet wood chips and all of that throws this approach
    off.

    I searched around and found that this type of indicator is extensively used
    by silo people and they call it a rotary paddle bin monitor and god is it
    expensive. We are not talking a $2 chip, we are talking about a solidly
    built $200 + motor unit.

    Maybe for now I have to continue sticking my head in there for a visual
    check every now and then...

    Uwe




    --- In basicstamps@yahoogroups.com, smartdim@a... wrote:
    > If it is safe to assume that when the amount of sawdust approaches the
    > "packed" state or gets to the packed state the mass (weight) will also
    > be measureably more than unpacked. Parallax sells a force sensor
    > called the flexiforce that is easy to use with the RCTIME command and
    > may work well for your application.
    >
    > see http://www.parallax.com/detail.asp?product_id=30056
    >
    > ken
    >
    > ________________________________________________
    > I don't know, I would be afraid of false alarms. There is sawdust all
    > over and I am interested in the particular moment where sawdust is not
    > only all over but starts to pack. That is why the paddle motor seemed
    > to make sense since I imagine it senses density and ignores light
    > density dust.
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]




    To UNSUBSCRIBE, just send mail to:
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    from the same email address that you subscribed. Text in the Subject and
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