Shop OBEX P1 Docs P2 Docs Learn Events
servo functions and limitations — Parallax Forums

servo functions and limitations

stbrnrdstbrnrd Posts: 35
edited 2009-08-01 17:46 in BASIC Stamp
Hello all [noparse]:)[/noparse]
i have a small dilemma dealing with a servo and their limitations...
i have a BSX that is running the majority of a project but have to result to manual switching due to the variables (i don't know if the servo will work) of a motor.· i would like to make the whole project to be ran from the stamp but i would need to know if the servo could oscillate at 10-50 Hz while moving a 90 gm piston and 120 gm of water for a distance of 4cm onto a reservoir.·
key factor making the stamp drive an optocoupled (parallax)servo to oscillate 10-50 Hz (tunable) without making the servo decrease the life-span drastically.
help would be greatly appreciated [noparse]:)[/noparse]
·

Comments

  • FranklinFranklin Posts: 4,747
    edited 2009-07-30 23:09
    Doesn't really sound practical. the servo gears would die in short order if they could move that fast in the first place.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    - Stephen
  • stbrnrdstbrnrd Posts: 35
    edited 2009-07-31 00:50
    that's what i was affraid off; is there a device asides from a conventional motor that could yield the same results - a controllable cycle of movement controlled by a relatively small form-factor controller?

    i'm glad i posted the question before finding out about the gears [noparse]:)[/noparse]) so thank you!!

    any help would be greatly appreciated.
  • stbrnrdstbrnrd Posts: 35
    edited 2009-07-31 00:57
    would it be feasible to make a stepper motor move in a 45° @ 10-50 Hz?

    i have a conventional motor moving a "locomotive-wheel" to get the same aeffect that a servo or stepper motor would be able to do (but in a far more controllable way); the way it's rigged at teh moment is very inneficient due to the gearing that has to be used along with a clutch, resistors and an itchy trigger finger [noparse]:([/noparse]

    thanks again!
  • $WMc%$WMc% Posts: 1,884
    edited 2009-07-31 01:07
    stbrnrd

    I think a solenoid would work better. Think about it.


    _________$WMc%________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there············································ BoogerWoods, FL. USA
  • stbrnrdstbrnrd Posts: 35
    edited 2009-07-31 01:17
    i did, there was a small issue with the power requirements of the solenoids i had available, and the energizing of the coil in that frequency range made a magnet the size of a 'AA' battery; which in the enclosure that they reside made some glitches with the stamp and the i/o pins.

    can you (if you know, wouldn't want you to search) suggest a solenoid that could fit in an enclosure the size of an Ipod (3x5x3) and run on less than 12VDC?
    ·
  • $WMc%$WMc% Posts: 1,884
    edited 2009-08-01 00:56
    stbrnrd

    Thats a good one.

    Other then goggle, I don't know!


    _______$WMc%____

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there············································ BoogerWoods, FL. USA
  • stbrnrdstbrnrd Posts: 35
    edited 2009-08-01 03:09
    Just touching bases -
    i started to wind a custom solenoid for this applicaiton, if it works i'll definitelly post my results. i just didn't know how difficult it would be to do all from scratch. searched in google for about 4.5 hrs and found very little hope, which is why i'm spooling copper on a nail [noparse];)[/noparse]

    but thanks for the insights and getting the gears grinding to a different speed [noparse]:)[/noparse]

    if you happen to come accross a 1oz-pull 3-8vdc solenoid.... pleaaaassse let me know [noparse]:)[/noparse]
  • danieldaniel Posts: 231
    edited 2009-08-01 03:51
    stbrnrd said...
    ...is there a device asides from a conventional motor that could yield the same results - a controllable cycle of movement controlled by a relatively small form-factor controller?

    Perhaps a peristaltic pump driven by a continuous-rotation servo or a small gearmotor/steppermotor?

    en.wikipedia.org/wiki/Peristaltic_pump
    www.instructables.com/id/recirculating-gravy-fountain/



    Perhaps a re-purposed aquarium diaphragm pump? They are typically solenoid driven (but at 110 VACfirst link below is for a battery operated one).

    www.drsfostersmith.com/product/prod_display.cfm?pcatid=3693&cmpid=03csepg&ref=3475&subref=AA&srccode=cii_5784816&cpncode=17-34656634-2
    www.patentstorm.us/patents/6164932.html

    Daniel
  • stbrnrdstbrnrd Posts: 35
    edited 2009-08-01 17:22
    thanks Daniel - looking into it, going to the local pet-shop to get one of the pumps and breaking it open [noparse]:)[/noparse] hope that gives me a beter direction.

    greatly appreciate the help fellas!!!
  • PrettybirdPrettybird Posts: 269
    edited 2009-08-01 17:46
    · They do have super servos I have been experimenting with. A bit tricky to tune but what a difference. Recomend direct witing off a breadboard. Possable they might fry the foil on a parallax circuit board under heavy loads. Metal gears make a difference.



    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320396615160&ssPageName=STRK:MEWNX:IT
    IMG_2919.JPG
    3072 x 2304 - 1M
Sign In or Register to comment.