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Harvesting Parts from a Magician Chassis — Parallax Forums

Harvesting Parts from a Magician Chassis

Martin_HMartin_H Posts: 4,051
edited 2012-10-03 09:56 in Robotics
The Magician Chassis doesn't appeal to me, but on paper it comes with nice parts. Similar GM motors from Solarbotics are $7.00 each, a similar battery holder is $4.00, and the standoffs with screws are worth around $2.00. So that's about $20 worth of parts with some other stuff I don't care about.

Is the quality of these parts descent or are they lower quality than similar parts?

Is the quality is good, what's the gear ratio on the motors?

How can they sell it so cheap?

Comments

  • mindrobotsmindrobots Posts: 6,506
    edited 2012-09-28 12:03
    It wasn't bad for an inexpensive test/play platform, wheels aren't always round, the plastic seemed brittle, the motors need encoders, they aren't balanced, the standoffs and battery holder are nice! :0)
  • ercoerco Posts: 20,256
    edited 2012-09-28 13:45
    The motors are geared all wrong: too fast, no torque. Gotta chuck 'em.
  • Martin_HMartin_H Posts: 4,051
    edited 2012-09-28 13:48
    erco wrote: »
    The motors are geared all wrong: too fast, no torque. Gotta chuck 'em.

    Since the gear motors were the major appeal, that nixes it.
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-09-28 14:01
    Maybe it's because I'm getting old, but I'm finding spending the time to work with inferior products just not a worthwhile expenditure of my remaining years. I got two Magician chassis (chasses? chassises? chassi?) and immediately discovered they were more trouble than I wanted at the moment, so I just switched to a couple of the metal micro gearmotors and wheels Pololu sells, and instant gratification. Yes, these also don't have encoders, the wheel options are toward the smaller diameter, and the price for everything is more than double. However they worked out of the box, and everything about them is infinitely better than the all-plastic motors. Plus they consumed a quarter of the gigawatts of the low-end Magician motors, thereby allowing more play time per charge.

    While I always appreciate saving money, my time is worth something, too. I figured I'm ahead of the game just chucking the crappy stuff.

    -- Gordon
  • ercoerco Posts: 20,256
    edited 2012-09-28 17:33
    I found the gearmotor & wheel combo provided positively dreadful. If you changed the wheels to half diameter or less, or if you doubled the gear ratio, it would work much better. Ironically, on Ebay I see just this motor & wheel combo for sale :( and also a 4WD chassis using 4 of them. Somebody make them stop!
  • Martin_HMartin_H Posts: 4,051
    edited 2012-09-28 18:24
    This is exactly why I asked the forum. You get what you pay for, and sometimes you just need a reminder of this.

    Gordon, I've never used Pololu micrometal motors, but they look good. I believe Pololu sells an adapter to Lego wheels as well which broadens wheel choices.
  • mindrobotsmindrobots Posts: 6,506
    edited 2012-09-28 18:28
    I have a couple go the Pololu 3pi robots and some micro metal motors. They've been no problem. I'll need to checkout the Lego adapter.

    That reminds me, I need to start saving for Pololu and Parallax Black Friday sales!!
  • ercoerco Posts: 20,256
    edited 2012-09-29 17:21
    Having said all that about these Magically Bad motors, I realize that this would be great candidate for experimenting with those $3 Ebay stepper motors.

    Duane, if you beat me to it, why I'll... you know it won't be pretty!
  • ercoerco Posts: 20,256
    edited 2012-09-30 19:35
    Apparently, the lack of fine motor control is directly proportional to the battery voltage, 11 volts of Lipo here.
    Plus, I learned a new word in Spanish! :)
  • mindrobotsmindrobots Posts: 6,506
    edited 2012-09-30 20:25
    You've always warned us about too much speed in these situations, master!
  • photomankcphotomankc Posts: 943
    edited 2012-10-01 11:58
    erco wrote: »
    Apparently, the lack of fine motor control is directly proportional to the battery voltage, 11 volts of Lipo here.
    Plus, I learned a new word in Spanish! :)

    office-space-bobs.jpg
    So what would you say...... this thing does here?


    Other than rocket off into collisions in a blur :)
  • ercoerco Posts: 20,256
    edited 2012-10-03 09:56
    Three days ago I went to Sparkfun.com to order another Magician to retrofit stepper motors onto. But they were out of stock, thus forcing me to scratch-build that little chassis at http://forums.parallax.com/showthread.php?142831-Old-School-Rapid-Prototyping

    Yesterday I got an email notification that suddenly they have 598 back in stock. Someone or something in the universe didn't want me to order it when I tried. Divine providence?

    But the one I have, retrofitted with CR servos, works fine. If I ever find one in blue for Sparkfun's $15 price I'll nab another.
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