Arduino, Sanguino, and newbies, oh my!

Hey all!

Well I've got some spending money burning a hole in my pocket, and I've been itching to get a Darwin up and running at home for a while. This weekend I cleaned up my workspace at home and got a desktop computer up and running with desk space that I think would be nicely used to have a Darwin running over there.

But now that I'm trying to buy something, I'm running into the age-old problem of documentation bitrot in this evolutionary design. Everything on the wiki is telling me that if I want to build the latest-and-greatest Repstrap, that I need an Arduino. But now that I'm looking around, the most recent references talk about Sanguino.

Also, I'm looking at the Stepper Motor 1.1 controller, but now I'm seeing parts lists for SMC's 2.0 and 2.1. If they are any cheaper than the 1.1 version, I'd be very interested in that -- it sounds crazy to me that the SMC 1.1 kits are each more expensive than the Sanguino kits.

I recognize that there's always some lag between what's in development on the "bleeding edge" and what's in production for us lay-people.

I'm not afraid of assembling boards, and if I need to, I can even get my own PCBs printed (though I'm more of a software guy than a hardware guy).

Anyone have advice for me? Should I hang onto my cash for a few weeks/months in order to get in on the next up-and-coming revision? Sanguino looks great, and I would really like to start running some stepper motors, but if the SMC 1.1 boards are two revisions back, I'd really like to see about using the SMC 2.1 plans (but I can't find references to them on any of the wikis).

Thanks!

--clint

Sitting next to my Arduino powered Darwin busily churning out replacement parts (hey, I'm super stoked, I think I can brag a little!), I'd say go for the Arduino. Yes, we'll likely move on to the Sanguino, or even something else bigger, better, badder and faster, but right now the Arduino works. Right this second, the Sanguino code isn't done yet, so if you build one of those, you might end up waiting a while for working code. I've got a Sanguino kit myself, but I'm waiting till there's some software out there before I try building it.

Besides, the Arduino's are great little devices. For $35 each, I bought two, and use one for testing out code without having to stop production on my Darwin. There's all sorts of uses for them besides Repraps. Within a day of getting mine in the mail, I had a little XY servo mechanism slaved to my mouse via Arduino and Processing. Sounds like Zach is going to make the code extendable anyway, so if you upgrade to a Sanguino, you can still use the old Arduino as an LCD controller or something. Maybe a laser range finder controller, who knows?

If you wait for the next version, you'll be waiting forever, as all this stuff is a work in progress. Get whatever is ready to go now, and start building. I'm using the stepper drivers version 1.1, and they work perfectly.

One thing I would do, is get the Arduino Breakout Shield - that makes wiring a lot simpler. And put screw terminals on the outputs of your stepper boards - the Molex connectors are OK, but a pain to put together, and a pain to change if you got the connection wrong.

On the other hand, if you really, really want to save money, wait a year or so. There will probably be a lot more Reprapped parts available at cheaper rates, and the electronics will be further refined.

But heck, it works now!

Wade

Edit - one more thing, go for some sort of closed loop extruder control. The open loop makes building things a lot more difficult. I'm using Zach's magnetic encoder, and Nophead has built a reprapped fringe wheel, but I don't think it's working yet. Nophead is using an optical encoder with about 200 counts I think.

I actually made an encoder out of an old mechanical ps2 mouse, but never got around to writing the software. As soon as I had it working, Zach came out with the magnetic encoder, which came with software, so it was easier for me to just use that.

Edited 1 time(s). Last edit at 10/24/2008 06:29PM by Wade.

Excellent, thanks for the updated state of the project -- that helps clarify things for a newbie like me.

Much appreciated!

Yeah i'd go along with the Arduino at the moment as well.

wait. I have. (mine is in the mail )

Hopefully by the time you get your first Rep(st?)Rap donw, there will be some experience with milling PCBs (Forrest is working on that) and perhaps more. so that you could improve/build another RepRap much more easily than if you wait.

Also, you sound like the kind of guy that would contribute to the project - it would be a shame to have you on the bench for so long

-Leav

Thanks for the advice, Leav.

I may very well go for the Arduino as well as a Sanguino -- they're so incredibly cheap, and seem like handy little processors to have around.

You're right -- I think I'm the sort of guy who would like to contribute to the project, and if the expandability of Arduino is tapped out, then I'm interested in helping write code for the Sanguino. If the only thing that doesn't work is code, that's fine -- I've written software to mess with g-code before (albeit on the computer side, not on the embedded side, but embedded c is what I do for a living). If I could help out by writing some new code for the project in order to get it working, that actually sounds like a lot of fun.

Especially reading on the RRRF blog ( [www.rrrf.org] ) that they got 60 more Sanguino kits in stock at the end of last month, I'm still going back and forth on this issue. If by getting a Sanguino I can help push development forward on this open-source project, I'm actually pretty okay with that. I'm more interested in tinkering with this project and advancing the technology than I am with actually building anything in particular.

But the processor decision is sortof a cheap one -- adding an Arduino is only an extra $35 or something, and I'm sure another processor could come in handy, and I'll probably just get both.


The next big thing that I'm still wondering about right now is the stepper motor board, since that's not /quite/ as cheap. What is the state of the revisions on that board? From the parts list, I see that the new boards use a completely different controller chip -- is that significantly cheaper or smoother or anything? If so, I'd be very interested in getting a cheaper stepper controller, as each one of those boards is such a significant chunk of change, that I'd like to invest in some good drivers.

Does anyone know the status on being able to order version 2.1 of the stepper driver boards?

Thanks!

--clint

If I am not mistaken, the RRRF has a policy where as they have to run out of the older version of the boards before they will ship the new ones....

It kindof makes sense - it is our foundation in a way and if we want it to be able to always order from stock, that means they have to have several sets lying around which are already bought and paid for. if we got the new boards every time they updated, and just leave the old ones in stock, the RRRF would collapse..

So basically, you should ask Zach both about the motor boards, and about helping out with the sanguino code. (you can e-mail him but he's a busy person so don't expect an instant reply)

Welcome Aboard

-Leav