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Home Built Motor Controllers — Parallax Forums

Home Built Motor Controllers

crgwbrcrgwbr Posts: 614
edited 2006-05-29 13:14 in Robotics
I am interested in Building two motor speed controllers to power my robot (Pefrerable 50+ AMP each).· I would like to use the PWM command to power a couple of mosfets.· Is this possible and/or a good idea?·

Comments

  • AmaRobotDudeAmaRobotDude Posts: 14
    edited 2006-05-18 16:20
    Its doable, theres lots of plans on the web but if you want to get your project going faster its easier to simpy purchase them. I built a couple small (5 amps) H-bridges from plans I found on the web and they worked out great.

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    So many hobbies, So little time.......and money [noparse]:)[/noparse]
  • crgwbrcrgwbr Posts: 614
    edited 2006-05-18 16:43
    Any suggestions of places to look for LARGE speed controller plans like that?
  • Pezi_Pink!Pezi_Pink! Posts: 32
    edited 2006-05-18 19:00
    There's a whole load of information and links to schematics/tutorials for all sorts of motor control circuits here. I would imagine you can find something suitable.

    [noparse]:)[/noparse]

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    Beware the pink squirrel!
  • Jim RicheyJim Richey Posts: 82
    edited 2006-05-18 22:35
    You might want to look this up on EBay. I've used this controller with fantastic results and it interfaces to your Stamp.



    80-Amp PWM DC MOTOR SPEED CONTROL (robotics
    Item number: 7620984595

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    Thanks, Parallax!
  • crgwbrcrgwbr Posts: 614
    edited 2006-05-19 12:22
    Thanks, now I just need a job, lol.· Know any places that hire 14 year olds?
  • FlyingFishFingerFlyingFishFinger Posts: 461
    edited 2006-05-20 23:54
    Same problem here...just got bumped from my attempt at a summer job[noparse]:)[/noparse] Reason: No hiring 15-year-olds.
    Blah.
    Rafael
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-05-21 00:55
    14 &·15-year olds need to find homes in the neighborhood without teen-agers of their own to punish and "hire" to cut their grass, rake their leaves, and do their choring.· C'mon guys, be/become enterprising and resourceful; it's called work for a reason (otherwise they'd call it fun.)
  • crgwbrcrgwbr Posts: 614
    edited 2006-05-21 20:41
    ya, I know, the catch is I'm allergic to grass and weeds. Last time I cut a medium sized law, I could hardly breath.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-05-22 16:26
    For 50amps, you might try building an H-bridge with Fets. Some go this high and can be controlled directly from a Stamp. I believe that some can be used in parallel too.

    Regarding work.
    I always wanted construction jobs, but California won't allow anyone under 18 to do the work -- too dangerous.
    Still, I managed to hustle apartment managers into keeping the common areas cleaned up in San Francisco.
    No grass.

    Mop, broom, and vacumn cleaner work. Make sure the laundry room looks reasonably civil. Possibly put out the weekly garbage, sort the stuff to be recycled. Washing windows can be very good too.

    Usually, this was a once a week deal of a few hours for each.
    If something else happened, you would get extra work. Sometimes, there is painting or cleaning an empty apartment.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-05-22 23:10
    crgwbr said...
    ya, I know, the catch is I'm allergic to grass and weeds. Last time I cut a medium sized law, I could hardly breath.
    I made most of my money when I was young performing chores for the elderly neighbors in my community. Hanging pictures, going grocery shopping (when I was old enough to drive), cleaning gutters, painting garages, washing cars, ...·basically anything besides mowing (except when the kid that did that was sick or on vacation).

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  • crgwbrcrgwbr Posts: 614
    edited 2006-05-24 19:18
    Does anyone know if you can get working papers in PA when your 14?

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    NerdMaster
    For
    Life
  • crgwbrcrgwbr Posts: 614
    edited 2006-05-26 21:02
    What do you guys think about these?· They look nice for smaller robots.

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    NerdMaster
    For
    Life
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-05-28 09:36
    Printed circuit boards can only handle about 5 amps and that is what it says. The 49amp MOSfet is nice, but you will burn up the board before you get there.

    Do you·know what size wire 50 amps requires?· It is huge, maybe 1/4 inch or more.

    When you try to put too much amperage through a printer circuit board, the copper will just melt or burn off of it.

    Why does a kid need 'working papers'? Usually, everything is just cash for chores. Most people would be glad to get someone dependable and not a theif for cash.

    Being able to earn you way is a significant boost to self-esteem.· The whole newspaper delivery system in
    America was based on that idea.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 5/28/2006 3:23:58 PM GMT
  • AmaRobotDudeAmaRobotDude Posts: 14
    edited 2006-05-29 04:11
    With those specs you might want to look at buying a controller. Heres a very good site that specializes in large scale controllers and such.....they are a bit expensive. burger.gif Look at the electronics section.

    www.robotmarketplace.com/store.html

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    So many hobbies, So little time.......and money [noparse]:)[/noparse]

    Post Edited (AmaRobotDude) : 5/29/2006 4:14:17 AM GMT
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-05-29 13:14
    Parallax's HB-25 is a very good controller that really will deliver all its power, not merely use some high amperage parts.
    I believe they are confident that it can control a 1/2 horsepower motor or roughly 25amps.

    Take a close look at what is involved. It has a cooling fan as well as protection circuits.·50 amps would require even more to be stable.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 5/29/2006 1:18:15 PM GMT
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