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Posted by D Herring on November 1, 2010, 6:36 pm
On 10/29/2010 01:12 PM, DA wrote:
> DA had written this in response to
>
http://www.www.roboticscommunity.com/robotics/Good-robot-arm-for-9-year-old-29259-.htm
> :
>> Hi all,
>> My 9-year-old nephew will be visiting for a couple months, and I
>> figured a robot arm kit would be good for him.
>> After a bit of searching, it looks like an OWI 535 is a good starter
>> arm that can be found for roughly $40. Any experience with it?
>> Can the kit motors be upgraded with servos?
>> With cheap motors and no sensor feedback, the OWI computer interface
>> doesn't look particularly useful. So I was wondering if I could put a
>> few hobby servos in to sequence with a USB servo controller (e.g. a
>> Pololu maestro).
> It's an old message and so you've probably already figured that out but
> the OWI arm is not much more than a toy. There is really no good way to
> replace the motors for servos and the motor couplings are not working well
> and let the motors slip all the time so it's nearly impossible to control
> either via PC using that interface or manually. I mean, we have to applaud
> the designers for putting a friction coupling on a toy arm at all (must
> save the plastic gears from shearing all the time) but they just make the
> whole experience a frustrating one. (this, by the way is my experience
> with the original OWI arm - I don't have an OWI-535 but something tells me
> that, since it's even cheaper, it would be a similar experience)
We went ahead and bought the OWI 535. It was a good supervised
building experience. We completed it over the course of a few
evenings, and he started learning how to build plastic models, use a
screwdriver, etc. He seems happy with its performance. Toy or not, I
think my expectations are much higher than his.
We can manually pick and place small blocks, etc. with no frustration.
It would not be easy to modify for servo control. Everything is
bolted onto the motor/gearbox modules; they are an integral part of
the structure.
Later,
Daniel
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