going to a arduino mega

i was wondering if i would be loosing anything major by going to a arduino mega over the other kits out there, it has more memory and ram, but it seems to be slower than the 20mhz the other kits include.

i am just trying to build my repstrap i am not very far along yet, so i thought i would start with the items that i need to learn the most about.

[mike-mack.blogspot.com]

is there anything else that i should be considering,


i am also trying to figure out if this stepper motor is strong enough for the extruder, i am sure it is more than good enough for the base plate, i plane on setting mine up much like mendle where the print head moves on the Y,Z axis
stepper

Edited 2 time(s). Last edit at 01/09/2010 10:37AM by dissidence.

Except you have to use one of the firmware forks (check mine and the forks on github), I see nothing wrong with the Arduino Mega.

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FiveD Firmware fork (supports Arduino Mega): [github.com]
reprapsource.com

I have an Arduino Mega ready to play with on one of my Repstraps I will get Mendel working first thou.

From the various posts on the forum here I don't think that 2.3kg/cm is strong enough for the extruder I think it needs to be more like 4.6kgm/CM well I will be trying a 4.6 Kg/cm with the hope that it has enough torque.

2.3kg/cm = 0.22555295 newton meter

4.6kg/cm = 0.4511059 newton meter

using the calculatore here http://www.onlineconversion.com/torque.htm

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Bodge It [reprap.org]
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BIQ Sanguinololu SD LCD board	BIQ Stepcon	BIQ Opto Endstop
BIQ Heater Block PCB	BIQ Extruder Peek clamp replacement	BIQ Huxley Seedling
BIQ Sanguinololu mounting	BIQ standalone Sanguinololu or Ramps mounting	Print It Stick It Cut it

My rep strap: [repstrapbertha.blogspot.com]

Buy the bits from B&Q pipestrap [diyrepstrap.blogspot.com]
How to Build a Darwin without any Rep Rap Parts [repstrapdarwin.blogspot.com]
Web Site [www.takeaway3dtech.com]

i was wondering if you ever ran into any trouble with the speed of the arduino, i know it is slower than the 20mhz of the the one they are using in the gen 3 motherboard. i was wondering if any one has run into troubles with that, i think it is close enough that it may be able to cope fairly well.

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[mike-mack.blogspot.com]

The motherboard also uses a 16Mhz crystal: [www.flickr.com]

The chip used (also on the arduions) can do 20Mhz, though.

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FiveD Firmware fork (supports Arduino Mega): [github.com]
reprapsource.com

oh i thought it was running at the 20mhz i wonder if i would gain anything if i tried to overclock it to 20mhz, but for now i will take stability over anything else though.

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[mike-mack.blogspot.com]

You wont be over clocking it running just running at is specified speed if you ran it at 25 MHz that would be overclocking.

You might have to change any software timing loops in the firmware if you change the clock frequency.

This PC is an over clocked dual core Pentium giving double the power/speed without any extra cost.

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Bodge It [reprap.org]
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BIQ Sanguinololu SD LCD board	BIQ Stepcon	BIQ Opto Endstop
BIQ Heater Block PCB	BIQ Extruder Peek clamp replacement	BIQ Huxley Seedling
BIQ Sanguinololu mounting	BIQ standalone Sanguinololu or Ramps mounting	Print It Stick It Cut it

My rep strap: [repstrapbertha.blogspot.com]

Buy the bits from B&Q pipestrap [diyrepstrap.blogspot.com]
How to Build a Darwin without any Rep Rap Parts [repstrapdarwin.blogspot.com]
Web Site [www.takeaway3dtech.com]

thank you, i am still learning allot about electronics, i am sure i will have a few more gaffs along the way, for that matter i still need to get more of the proper tools, witch i dont have the money for right now has well. but i will get them in time too.

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[mike-mack.blogspot.com]

My first processor I overclocked was my Nascom Z80 CPU in the late 70's
Next was an Atari Mega to get a DTP aplication working faster.
On the old 486 DX mother boards I just changed the Xtal osilator on a 25MHz board to a 33Mhz one..

There is a risk in over clocking though and that is over heating the proccesor chip I have been very luck never having killed a CPU from over clocking it.

You can also cause memory accsses problems if you are not carefull and certainly render any badly writem programs useless. These are programs that rely on timing loops created by instruction processing times.

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Bodge It [reprap.org]
=======================================

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BIQ Sanguinololu SD LCD board	BIQ Stepcon	BIQ Opto Endstop
BIQ Heater Block PCB	BIQ Extruder Peek clamp replacement	BIQ Huxley Seedling
BIQ Sanguinololu mounting	BIQ standalone Sanguinololu or Ramps mounting	Print It Stick It Cut it

My rep strap: [repstrapbertha.blogspot.com]

Buy the bits from B&Q pipestrap [diyrepstrap.blogspot.com]
How to Build a Darwin without any Rep Rap Parts [repstrapdarwin.blogspot.com]
Web Site [www.takeaway3dtech.com]

i can tell you have been at it allot longer than i have been the first ones i got to play on were my grampas and uncles 286's they had an older one than that that was one piece and had to load the old 5 1/4 in floppies i cant remember its name but it was just a mono green text screen

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[mike-mack.blogspot.com]

the oly real difference between the mega and the others is the pin layout/s, and even these are minor changes, so if yo are willing to encounter a few "minor hassles" figuring it out, feel free to use the standard firmware, and just tweak it to suit yourself.
Buzz.

thats always good to hear, i hope to use it to the best of my ability, though right about now i kinda wish i could get the same one they are using for a better price, yay for tight funds

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[mike-mack.blogspot.com]

i did find this guy it seems to be the same has the arduino mega, but is a good chunk cheaper, [www.robotshop.ca] so i am going to buy it this week i hope, gotta wait for the funds to transfer still.

has any one else here used them before, from what i can tell they are a Japanese company and it is the same has the arduino mega.

i am sure i can flash it with the firmware i would need if it was not the same already

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[mike-mack.blogspot.com]

Dissidence

I have a couple of the same boards, I don;t have a real arduino mega for comparison but they work fine. Their crystal is 16Mhz.

I use atmega168's with 20mhz crystals. If you want to do this though you need to tweak the crystal speed settings in the arduino definition's files or the uart speeds etc will be wrong and you won't be able to talk to it from the PC.

Easiest route is to stick to 16mhz for now.

Re The mega it has twice the memory of the sanguino (128k versus 64k) and a bunch more IO. But runs all the same code with little modification, speed of operation will be pretty much the same because the processor core is the same. for the firmware you will need to edit the pin definitions whuch are defined as constants in the top ot the sketch file. These specify which pins do what. Then make sure youconnect up the pins to match your definitions. It could be worth your while if you are just startign out to see if someone else has got a file ready to go that you can blag a copy of.

Take a quick swing past the firmware section of the forum, the arduio firmware is currently undergoing an (Triffid_Hunter) update that should make it faster. (replacing floating pint with scaled arithmetic etc) if you are worried about speed head this route.

[dev.forums.reprap.org]

Hope this helps.

Cheers

aka47

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Necessity hopefully becomes the absentee parent of successfully invented children.

i did order my aurdino mega board, so i am jus waiting for paypal now. but thank you for your advice, i hope that i can start to learn more about it soon. i don't think i will be doing too much fiddling with speeds just yet, i dont know why but i am inclined to try to use both the mega and and arduino one to just work the steppers and the mega to do the work, kinda like a duel core cpu, i am sure i will get the idea out of my head some time soon

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[mike-mack.blogspot.com]

dissidence

I owe you an apology, I had already given you much the same in another thread. Serves me right for posting at silly o'clock in the morning. I am not stalking you honest guv.

I am personally a big fan of multiprocessor, and liked the original electronics method of a serial bus with many processors linked to achieve the tasks. it made it all very modular and of course the more you add the more processing power you add, so it scales fairly well.

A lot of people fail to realize how many processors reside in the average PC/Workstation each doing their own tasks in parallel and freeing up the main CPU from too much trivia.

Nopheads current extruder head design with it's own dedicated processor is a most excellent case in point.

aka47

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Necessity hopefully becomes the absentee parent of successfully invented children.

ah no worries, but i will get my project going first then i will try to learn how to do what i want.

but i do think this was the better rout to go hardware wise. i think this will become the more common one soon,

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[mike-mack.blogspot.com]

thanks for the vote of confidence, I think I need to press ahead and get a backplane and controller board design knocked out for the Arduino Mega.

aka47

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Necessity hopefully becomes the absentee parent of successfully invented children.