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Faster Motors for BOE-Bot??? — Parallax Forums

Faster Motors for BOE-Bot???

RoboticsProfessorRoboticsProfessor Posts: 54
edited 2008-10-24 00:18 in Robotics
I'm just finishing a line maze bot with BOE-Bot, and I can see it does the maze well.

But in a "fastest time" contest, I'd be in trouble.

Anybody have any experience with faster servos?
Or will I have to replace servos with motors to get more speed?

Comments

  • SRLMSRLM Posts: 5,045
    edited 2008-10-21 06:23
    The Parallax servos are .28s for 60 degrees.

    This servo is .15s for the same

    While this servo is .11s. You'd have to modify this one to continuous rotation.
  • SRLMSRLM Posts: 5,045
    edited 2008-10-21 06:23
    You could also just get bigger wheels.
  • iDaveiDave Posts: 252
    edited 2008-10-21 06:53
    Thanks for the info SLRM..I've also been looking for a faster servo for my telepresent robot

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  • FranklinFranklin Posts: 4,747
    edited 2008-10-22 02:26
    Or get some of these www.pololu.com/catalog/product/993 as seen here www.pololu.com/catalog/product/975

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    - Stephen
  • SRLMSRLM Posts: 5,045
    edited 2008-10-22 03:00
    Personally, I'd stick with servos: they are drop in replacements for the same price as the motors (at least the pololu one is). However, at 440 RPM the motor is certainly faster.
  • ercoerco Posts: 20,256
    edited 2008-10-22 17:13
    You can speed up your existing servos somewhat by increasing their supply voltage from 6 volts to 7.5. Jumping to 9 volts is pushing it. Make sure your Stamp gets regulated 5 volts.

    Some servos are definitely faster than others, if you want to check specs and swap them out. But I agree with Franklin that replacing servos with gearmotors will give you the widest range of speed & torque. Pololu and Solarbotics both offer a variety of gearboxes (brass and plastic, each available·in multiple gear ratios) and the Pololu·dual motor controller is small, cheap and works well: http://www.pololu.com/catalog/product/411.·You can use up to 9 volt motor supply voltage. The controller adds "set & forget" speed control so you don't have to send a continuous string of pulsouts to keep your motors moving, so you're free to monitor your sensors and react accordingly.

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    ·"If you build it, they will come."
  • gelfling6gelfling6 Posts: 60
    edited 2008-10-24 00:18
    I did a little cross-platform working a few years back, between the VEX robotics system( Pre-IFI, When Radioshack sold BOTH), and the Parallax BOE-BOT. I was surprised, the VEX motor modules ran a little faster rotation, when driving them off the BOE & the Homework boards. The output frequency was (a) a little wider, and (b) offset a few Hz., but virtually identical operation..

    I also ran into a few fairly easily servos at a local RC-Hobby store, which ran a little faster too, but were a bear to modify to constant rotation. (mechanically, easy, but connecting a 5K Trim-POT to the outside, was tough.. too much signal drift.
    they seemed sensitive to RFI.) I bought a pair, with the idea of replacing the stock CR-Servos from Parallax, which were beginning to "Scream" (motor bearings worn. result, massive armature chatter.)..

    Stephen
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