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HB25 question — Parallax Forums

HB25 question

RontopiaRontopia Posts: 139
edited 2007-04-23 15:14 in Robotics
I have been wanting to buy a new "base" for some time. I have bought a bunch of componets to that end. I am looking at or thinking about this http://www.lynxmotion.com/Category.aspx?CategoryID=57. the thing is it has 4 motots.

so im thinking i can hook them up in parallel and drive each side with one HB25. is that possible?· even in parallel they wont draw enough current to even come close to hurting the drivers.

also any other bases out there that you guys like?


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IC layout designer
Austin Texas

Comments

  • WhitWhit Posts: 4,191
    edited 2007-04-16 19:20
    See "check out my new robot" post below or see this link.

    http://www.lynxmotion.com/images/html/proj071.htm

    cabojoe might have some good insights.


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    Whit+
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-04-16 19:37
    Hello,

    The HB-25 can accept multiple motors on one HB-25 that will be driven at the same relative speed/direction. That is, connected with the same polarity a second motor (of the same type) will move in the same direction and speed. Likewise connecting it with the polarity reversed will cause the speed to match by the direction to be opposite. If the maximum stall current of both motors is under 25A you should be fine. Take care.

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    Chris Savage
    Parallax Tech Support
  • RontopiaRontopia Posts: 139
    edited 2007-04-16 20:13
    thats what I figured.. thanks

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    IC layout designer
    Austin Texas
  • RontopiaRontopia Posts: 139
    edited 2007-04-16 21:22
    any other bases that look better? I was hoping for one a little bigger. maybe 12 x 12

    I have been looking for a while and short of building my own this is the closest thing i can find.. (link in first post)

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    IC layout designer
    Austin Texas
  • T0mT0m Posts: 124
    edited 2007-04-17 01:26
    I have 6 gear motors ( 3 on each hb25 ) and they work fine.
    Tom

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  • crgwbrcrgwbr Posts: 614
    edited 2007-04-19 12:08
    This base seems to be a good deal: http://www.hobbyengineering.com/H1506.html

    It's not quite as big as you wanted though.

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    Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning.

    Microsoft: "You've got questions. We've got dancing paper clips."
  • RontopiaRontopia Posts: 139
    edited 2007-04-19 14:22
    thanks.. I have looked at tho's and came to the same conclusion.. not quite big enough. also.. I have decided not to use a tracked bot. they look cool but the truth is its more moving parts that in the end have never given me anything but trouble. Im sure in the future I will use tracks on another bot, but for now im wanting to have something that is more reliable.

    im still looking for something better than the lynxmotion rover, if anyone has any ideas.

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    IC layout designer
    Austin Texas
  • PARPAR Posts: 285
    edited 2007-04-19 18:52
    Rontopia said...
    im still looking for something better than the lynxmotion rover, if anyone has any ideas.
    What do you want the "base" to _do_ for you? So far, you've only mentioned "looks". size, no complex, prone-to-failure parts, and maybe not four drive motors?

    Lots of people toss or sell for a few bucks their old RC cars (look for them in garage sales, recycle stores). Those chassis can be cannibalized for parts (wheels, suspensions, drive trains, motors and gearbox, electronics (RC, H-bridge), etc. Adapting them to be under partial control of a Stamp, adding sensors, etc, ·provides a cheap "base" as well as an interesting project in system integration.

    PAR
  • RontopiaRontopia Posts: 139
    edited 2007-04-19 19:16
    your right.. I really havent defined what i was looking for.. sorry about that.

    what i really want.

    1) a bot that can navigate indoors and out. in is more important but I do want something that can do light outdoors traversing.

    2) bot must be able to go at walking speed

    3) have a 12 pound payload

    5) big enough to carry a small x86 computer(way future) micro atx board? or is it a mini atx? I cant remember which is···· smaller at the moment.. the one i have in mind is about 9" x 8"

    6) 12v motors.

    I spoke with lynxmotion and the guy there told me that the 4x4 rover is limited by the tires as far as weight. the tires he said are hollow and after about 6 to 8 pounds start to depress. other than that this rover is just about what im looking for. its about 2 to 3 inches smaller in long ways that I want. the only other thing I would like to have is something that is quite. geared motors make alot of noise, I was really hoping to find something that is rather quite. dont know if that exists..

    this should be a good platform that will last through many many changes that im sure i will test or make.

    the only reason I ask the question is that some of you may know of some website I have not seen before? with a base that is better or costs less. 178.00 or so is not bad really.

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    IC layout designer
    Austin Texas

    Post Edited (Rontopia) : 4/19/2007 7:22:43 PM GMT
  • John AbshierJohn Abshier Posts: 1,116
    edited 2007-04-19 19:52
    Rontopia, Zagros Robotics bases may meet your needs. https://www.zagrosrobotics.com/Index.asp
    Another vendor with many bases is Trossen Robotics
    http://www.trossenrobotics.com/store/c/2658-Differential-Steering.aspx
    Regarding the hollow tires. It may be possible to fill them with something, expanding foam or some type of plastic. In the MIT 6.270 course they fill lego tires with rubber bands to keep them from collapsing.

    PS.· If we win the lottery, the MMP-30 would be nice.·
  • RontopiaRontopia Posts: 139
    edited 2007-04-19 20:51
    HOLY Smile!! im in the wrong business. 500+ bucks for some of these things? are you kidding me?

    one of them looks like a RC truck with the body pulled off and a flat piece of PVC attached.. 500 big ones. wow and those 5000 dollor bases.. even if the wife would let me spend that much on my hobby, 5000 bucks!! wow.

    anyway thanks for the links. I will read up on these.

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    IC layout designer
    Austin Texas

    Post Edited (Rontopia) : 4/19/2007 8:56:09 PM GMT
  • crgwbrcrgwbr Posts: 614
    edited 2007-04-20 11:56
    Rontopia said...

    5) big enough to carry a small x86 computer(way future) micro atx board? or is it a mini atx? I cant remember which is smaller at the moment.. the one i have in mind is about 9" x 8"

    Go for a mini-ITX or nano-ITX. Mini-ITX ($150-$200 with processor) boards are 170mm X 170mm. Nano-ITX motherboards ($300+ with processor) are 120mm X 120mm. The nano's are about as small as your going to get for a motherboard, they are made by VIA corporation.

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    Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning.

    Microsoft: "You've got questions. We've got dancing paper clips."
  • RontopiaRontopia Posts: 139
    edited 2007-04-23 15:14
    i have looked at tho's and they just dont have enough bandwidth. but thanks for the in put.



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    IC layout designer
    Austin Texas
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