What's the best solution for a homebuilt robot arm?

[Chriszuma]

So basically, I want to build a robot arm this summer as a side project. I was looking at a few different microcontroller/servo controller solutions, and I was wondering if anyone has experience with any of these, or can offer some advice.

The first one I was looking at is the Make Controller. It's a fully-featured controller and dev board with 4 servo controllers, and built-in networking and lots of useless stuff like that. It is $150. Link.
Then, there is also the Gumstix platform, which is a linux computer the size of a stick of gum, with different expansion boards. There is one expansion board, the robotstix, which has 6 servo controllers. However, this seems much more complicated to program and configure. It would also run about $150. Platform and Expansion boards.
Parallax makes a cool USB 16-servo controller for $40, which would be fun to play around with but wouldn't be suitable for a standalone robot arm. Link.

There are also a plethora of basic stamp and PIC development platform out there, but I don't want to use a basic stamp because I hate basic, and I can't seem to find a reasonable PIC platform. I'm good at figuring things out like this, so a steep learning curve isn't that much of an issue. What I am primarily concerned with is how much effort each one of these will take to work with, so if anyone has tried them, I'd like some insight.

Thanks.

[KenWittlief]

what do you want the arm to be able to do once you have it assembled and tested?

[Chriszuma]

Originally Posted by KenWittlief

what do you want the arm to be able to do once you have it assembled and tested?

Basically I just want to build it for the sake of building a robot arm. Ideally I'd like it to be able to manipulate small objects, maybe even draw pictures with a pen. (yes, I know there will be crazy math involved, that is half the point)

[sanddrag]

How much are you looking to spend total on the project?

EDIT: Perhaps you'd be interested in building a CNC router instead? Check out www.cnczone.com

[Chriszuma]

Originally Posted by sanddrag

How much are you looking to spend total on the project?

For the controller I was hoping to keep it around $150 or thereabouts. You have to understand though, my projects don't exactly work on a budget. I just funnel my expendable funds into them until they are done. Of course, I don't want to end up spending thousands on this, maybe in the few-hundred range.

[KenWittlief]

it might help if you think through the applications you want to use it for.

One idea, a few years back the team I was on purchased our own button machine. It was hand operated and there were several steps involved to make one button.

A couple of mentors were kicking around the idea of automating it for a summer / fall student project - either using pnuematics to drive the levers, or making a pick and place 'robot' to feed the materials into it.

I always have a problem designing generic stuff "generic computers, generic robots...." but if you tell me what you want the system to do then everything falls into place for me and I can proceed with a logical plan /approach. Thats why I recommend you approach this project in the same manner.

Theres lots of creative things you could do with a robot arm - teach it to play the piano, or a classical guitar, design one to airbrush designs onto tee shirts - design one to open your mail and feed the contents directly into a paper shredder (I need one of those!) If you know what you want it to do, then you can design it accordingly. Designing a generic robot arm that can do 'anything' is open ended - it will drive you insane trying to define the design.

[Chriszuma]

Originally Posted by KenWittlief

it might help if you think through the applications you want to use it for.

One idea, a few years back the team I was on purchased our own button machine. It was hand operated and there were several steps involved to make one button.

A couple of mentors were kicking around the idea of automating it for a summer / fall student project - either using pnuematics to drive the levers, or making a pick and place 'robot' to feed the materials into it.

I always have a problem designing generic stuff "generic computers, generic robots...." but if you tell me what you want the system to do then everything falls into place for me and I can proceed with a logical plan /approach. Thats why I recommend you approach this project in the same manner.

Theres lots of creative things you could do with a robot arm - teach it to play the piano, or a classical guitar, design one to airbrush designs onto tee shirts - design one to open your mail and feed the contents directly into a paper shredder (I need one of those!) If you know what you want it to do, then you can design it accordingly. Designing a generic robot arm that can do 'anything' is open ended - it will drive you insane trying to define the design.

Ideally, I'd like to be able to draw designs with it, with a pen on the desk, or an airbrush on a vertical surface. That, and it would be sweet if it could do other random stuff like make toast.

Mostly it's just for the fun of building a computer controlled robot arm.

[=Martin=Taylor=]

What about hacking a printer?

It may not sound very creative, but you can get old printers for cheap and program the stepper motors (or replace them with something else).

If you want it to paint instead of squirt ink just replace the printer head with a brush.



It sounds a little too simple, so there's probably something I'm missing, but at least its a start.

[Chriszuma]

Originally Posted by Hachiban VIII

What about hacking a printer?

It may not sound very creative, but you can get old printers for cheap and program the stepper motors (or replace them with something else).

If you want it to paint instead of squirt ink just replace the printer head with a brush.



It sounds a little too simple, so there's probably something I'm missing, but at least its a start.

Yeah, there is something you're missing. The point here isn't to be able to airbrush. The point it to build a robot arm. The airbrushing is just sort of a bonus. I would be perfectly happy if all it did was dance around.

[brainonska]

it really depends on what you want to use the arm for
also it sounds like you are describing a gripper "hand" not a arm
for most uses I find parallel grippers the best because objects slip
out when you uses hinge grippers

[sanddrag]

Originally Posted by Hachiban VIII

What about hacking a printer?

It may not sound very creative, but you can get old printers for cheap and program the stepper motors (or replace them with something else).

Good idea. Stepper motors seem like a lot of fun.

[Chriszuma]

Originally Posted by sanddrag

Good idea. Stepper motors seem like a lot of fun.

I disagree. That sounds infinitely more complicated than using servos.