using old computer electronics in place of arduino kits

I have 3 old imacs. I am trying to make my reprap with as little money as possible, so I want to figure out a way to use old computer electronics instead of paying for arduino kits. I believe if I can succeed at this, and post my results, it will help reprap go viral because it will attract people who like to make stuff out of old things for fun and environmental reasons, and it will make the reprap that much more accessible to people low on funds in this harsh economic climate. Old computers are widely available.

I have joined the DIY community only recently so I am not too savvy yet with electronic hardware, nor do I have any real programming knowledge. From my research it appears to me whether this will work or not is all about the firmware on the hardware. If it can be removed, will the reprap firmware be compatible with the hardware? If it cannot be removed, is there away I can work with the firmware that is on it? Like can I add software on top of it or could the firmware itself work for the reprap applications?

You will create more problems (and cost) this way.

PCs do not have large numbers of GPIO (digital IO) pins (which are needed to control the motors and the heaters, and to read the end stops) or any analog IO pins (to read the temperatures). The nearest you will find to the digital IO is the parallel printer port.

So you will have to redesign your RAMPS (which gets attached to the arduino) and build it from scratch. That will cost more than buying a kit or a ready assembled unit.

David

It might be theoretically possible to use an old computer in place of a Arduino, but you will still need all the stepper drivers, mosfets, etc anyway.

Also, there will be no one size fits all solution. Every different computer would require a different process. Months of labor isn't worth the $30 for an Arduino.

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www.Fablicator.com

... the firmware moves the motor and controls the temperature ...beside decoding received strings and such.

You would have to programm all this functions on your own and solder an adapter between your computer and all the hardware/electronic bits you can't realize with the computer.

If your programming skills and electronics experience is low, then better buy a common electronic and try only to adapt the host software ...

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Viktor
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o so there is no way to get around paying for all the electronics, i was hoping that i would be able to salvage everything from some old commodity and only have to pay for the printed parts, what a bummer

kyleeamonahern Wrote:
-------------------------------------------------------
> o so there is no way to get around paying for all
> the electronics, i was hoping that i would be able
> to salvage everything from some old commodity and
> only have to pay for the printed parts, what a
> bummer


You'd have to buy stuff anyway, unless you have old appliances that you can salvage five NEMA 17 motors from, and you happen to have M8 threaded and smooth rods and a large number of miscellaneous metric fasteners lying around (not to mention the extruder parts). If you're concerned about the price of the electronics, get this kit that includes a Sanguinololu board, four Pololu drivers, and all the endstops you'll need. It's a steal for $105, and you'll wind up with a perfectly good machine that uses standard electronics that people can help you debug and hack on.

how hard would it be to put everything on a PCIe card?

There are several problems to put all this in a PCI card format.

1) Power (you need more power than you can get from the bus)
2) Are your old computers so new the have PCIe?
3) The glue logic for handling the bus plus the PCB you need to create are more than $100.
4) The timing of a modern computer is not as predictable as a small microcontroller (you may end up having trouble even if you succeed all the former).

Of course, it still can be done, but it will cost you more time and money that the alternatives (even if you succeed which is uncertain).

That's my two cents,

misan

1) PCIe is 12v and if you need the power of another rail just do what the high end graphics cards do and have another molex.
2) I wasn't the OP
the other two may be good points though.

kyleeamonahern Wrote:
-------------------------------------------------------
> o so there is no way to get around paying for all
> the electronics, i was hoping that i would be able
> to salvage everything from some old commodity and
> only have to pay for the printed parts, what a
> bummer

That's what I did :
[forums.reprap.org]

Almost everything is salvaged (steppers, stepper drivers, power supply, mechanics.

But it takes A LOT of time, I started the project on February and I only began to print some test cubes this week.
OK, it is not only a 3D printer but also a mini-mill, PCB engraver and lathe but that's still a lot of time.

Even if you don't start from scratch like me, I think you can find many components from old equipments like printers and scanners.
Old Epson printers have good NEMA17 steppers motors.
You can also find other parts like smooth rods, brass bushings, timed belts, timed pulleys, opto end stops, gears, springs for the leveling platform, glass for the bed...

Awesome thanks! thats exactly what I was planning on doing. I have a fax machine/scanner and another printer. Its nice to hear someone has accomplished this, but do to the time I think I will build my first one the normal way.

Once I have one up and running I want to try to develope a generalized plan for salvaging as many parts as possible and post it on the internet. I think that's how a sizeable amount of the reprap community will develope in the future; mainly in poorer regions. Thanks a lot for your encouragement, much gratitude, and thanks to all others who have responded. I have found all the advice useful.

That is awesome. Do you have a blog or anything that shows step by step what you did?

Edited 1 time(s). Last edit at 11/03/2011 01:18PM by kyleeamonahern.

I don't have a blog, but I use the forum to share my progress.
I made a topic for the extruder : [forums.reprap.org]
and for the extruder/bed controller : [forums.reprap.org]

And do up a wiki page on which old printers have the best salvageable parts.

My Prusa is using two Epson stepper for X and Y axis savaged from two old printers. Not only the motors but the belts and pulleys are useful. They are working nicely and saved me more than fifty bucks.

misan