Good robot arm for 9-year-old?

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).
Any recommendations on another good, cheap kit?
Thanks, Daniel
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
DA had written this in response to http://www.www.roboticscommunity.com/robotics/Good-robot-arm-for-9-year-old-29259-.htm :

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)

If the usual suspects like the Lynxmotion arm are beyond the budget, take a look around for older SAM kits (or built robots). They are servo-based (5 servos) and were pretty solidly built (although the servos may or may not have survived - depending on what they've been through)
I have also seen servo sellers on eBay sell kits of plastic parts to build a simple 4 or 5 DoF arm using 4 or 5 of their servos - it's hard to refer to the product because I don't believe I've ever seen it named, just look for robotic servo arm or something to that effect.
Good luck!
##-----------------------------------------------## Delivered via http://www.roboticscommunity.com/ Web and RSS access to your favorite newsgroup - comp.robotics.misc - 13723 messages and counting! ##-----------------------------------------------##
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 10/29/2010 01:12 PM, DA wrote:

http://www.www.roboticscommunity.com/robotics/Good-robot-arm-for-9-year-old-29259-.htm
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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.