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Semi-OT - servomotor circuit — Parallax Forums

Semi-OT - servomotor circuit

ArchiverArchiver Posts: 46,084
edited 2003-03-07 15:53 in General Discussion
I've just had the opportunity to recover some Honeywell modulating
motors that are not operational. After examining them I've determined
that the fault is thier position feedback gizmo. What they use is two
semi-circles of (apparently) painted on resistive material around the
shaft and a couple copper arms that slide over them. Basically just a
big variable resistor. The resistive material has worn through to the
PCB underneath so the feedback is no longer operational.

Would anyone happen to know if I can purchase a paint-on resistive
material at all? I can use an ohmmeter to find out the ohms per inch
or whatever.

If I get these functional I can have some great fun interfacing them.
At 80lbs torque they'd be capable of some real work. I'd just have to
cook something up!

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-03-07 14:56
    Possibly the resistive paint used in car rear windows
    for defrosters could work. You 'paint' this stuff on,
    and then heat it with a heat gun (I think 800 degrees)
    to cure it. If the disk will take the heat, this
    could work. My Honda dealer had the stuff for
    repairing rear window defrosters.

    --- In basicstamps@yahoogroups.com, "ghidera2000" <ghidera2000@y...>
    wrote:
    > I've just had the opportunity to recover some Honeywell modulating
    > motors that are not operational. After examining them I've
    determined
    > that the fault is thier position feedback gizmo. What they use is
    two
    > semi-circles of (apparently) painted on resistive material around
    the
    > shaft and a couple copper arms that slide over them. Basically just
    a
    > big variable resistor. The resistive material has worn through to
    the
    > PCB underneath so the feedback is no longer operational.
    >
    > Would anyone happen to know if I can purchase a paint-on resistive
    > material at all? I can use an ohmmeter to find out the ohms per
    inch
    > or whatever.
    >
    > If I get these functional I can have some great fun interfacing
    them.
    > At 80lbs torque they'd be capable of some real work. I'd just have
    to
    > cook something up!
  • ArchiverArchiver Posts: 46,084
    edited 2003-03-07 15:06
    Years ago I purchased a pen that one used to write circuit traces onto
    just about any surface... I do not know if it would hold up in your
    situation, but it might be worth a look....

    A quick google search game me a couple of links:

    http://www.contacteast.com/product/prodpage.cfm?grp=4088BDCD-EEE0-11D4-8
    A710050DA5FEB55

    http://www.circuitspecialists.com/level.itml/icOid/823

    --Aaron

    Original Message
    From: ghidera2000 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Tl-YdPrKif2ctvw4PB6ewfkkUHy67jWNbJq2b7R_r15ZEVYnp1mJS0wNtBsdhlLWSnj0ud_T1Sr8x4sWKw]ghidera2000@y...[/url
    Sent: Friday, March 07, 2003 6:01 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Semi-OT - servomotor circuit


    I've just had the opportunity to recover some Honeywell modulating
    motors that are not operational. After examining them I've determined
    that the fault is thier position feedback gizmo. What they use is two
    semi-circles of (apparently) painted on resistive material around the
    shaft and a couple copper arms that slide over them. Basically just a
    big variable resistor. The resistive material has worn through to the
    PCB underneath so the feedback is no longer operational.

    Would anyone happen to know if I can purchase a paint-on resistive
    material at all? I can use an ohmmeter to find out the ohms per inch
    or whatever.

    If I get these functional I can have some great fun interfacing them.
    At 80lbs torque they'd be capable of some real work. I'd just have to
    cook something up!




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  • ArchiverArchiver Posts: 46,084
    edited 2003-03-07 15:53
    you might go to a auto store and check out the stuff
    they use to repair rear window defrosters it comes
    in a little bottle like nail polish it's a type of
    conductive ink with some resitence in it you would
    have to experiment i have heard of people reparing
    potentiometers with it [noparse]:)[/noparse]
    --- Aaron Bond <abond@q...> wrote:
    > Years ago I purchased a pen that one used to write
    > circuit traces onto
    > just about any surface... I do not know if it would
    > hold up in your
    > situation, but it might be worth a look....
    >
    > A quick google search game me a couple of links:
    >
    >
    http://www.contacteast.com/product/prodpage.cfm?grp=4088BDCD-EEE0-11D4-8
    > A710050DA5FEB55
    >
    >
    http://www.circuitspecialists.com/level.itml/icOid/823
    >
    > --Aaron
    >
    >
    Original Message
    > From: ghidera2000 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=RTEpEC2uPPrju5P4O_5Bbd0XWs9g-mwG65wXj0eD-KCQBJmJFM0EWnqOSRba6JIfbhPXnRKm9YVpuK6mglLa]ghidera2000@y...[/url
    > Sent: Friday, March 07, 2003 6:01 AM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Semi-OT - servomotor circuit
    >
    >
    > I've just had the opportunity to recover some
    > Honeywell modulating
    > motors that are not operational. After examining
    > them I've determined
    > that the fault is thier position feedback gizmo.
    > What they use is two
    > semi-circles of (apparently) painted on resistive
    > material around the
    > shaft and a couple copper arms that slide over them.
    > Basically just a
    > big variable resistor. The resistive material has
    > worn through to the
    > PCB underneath so the feedback is no longer
    > operational.
    >
    > Would anyone happen to know if I can purchase a
    > paint-on resistive
    > material at all? I can use an ohmmeter to find out
    > the ohms per inch
    > or whatever.
    >
    > If I get these functional I can have some great fun
    > interfacing them.
    > At 80lbs torque they'd be capable of some real work.
    > I'd just have to
    > cook something up!
    >
    >
    >
    >
    > 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/
    >
    >
    >
    >
    > 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/
    >
    >


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