Driving a mix of G3 and pololu steppers from G3 motherboard

Hello All

As per my other posts I have blown one of my Makerbot G3 stepper controllers. Although I have decided the cost effective option is to replace the chip as per this post, I had considered replacing the blown stepper controller with a pololu one.

That raises the question of how hard/easy would it be to drive a mix of G3 and pololu stepper controllers from the G3 motherboard. Obviously I would need to build a shield(is that the term?) for the pololu with the neccesary power and data connections as well as the endstop but then what about the firmware? Would special programming be required?

Has anyone succesfully achieved this? (I am sure there must be)

Cheers

Yes,

for a brief while, I had the Sanguino connected to Pololu drivers, before I migrated to TZ electronics.
I have not checked the Pololu updates, so there may have been changes in the Wiki; but basically the process was as follows:
1. build the Pololu strip board, as per pololu wiki - Adrian basically designed this circuit, and I added 1.5A fuses just in case
2. Investigate the ATMega644p pinouts on the sanguino schematic, and match step, dir, rst pins to pololu board inputs
3. Identify appropriate pins on IDC headers for X- Y- and Z- stages.

No changes in firmware is required.

This worked for me. YMMV

Regards
Marius

This one looks good: [www.thingiverse.com]

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-Nudel
Blog with RepRap Comic

the stepper controller doesn't use the end-stops. they pass through the stepper board untouched and go directly to the motherboard.

the A4983 needs a heatsink. cheap stick-on RAM heatsinks are apparently adequate

don't forget decoupling caps!

let us know how you go

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Wooden Mendel
Teacup Firmware

Quote

Has anyone succesfully achieved this? (I am sure there must be)

Yes we have and this is what we did

Ok...... the machine on this thread uses a techzone motherboard with Pololu boards set to 1/16 step for X&Y, 1/2 step Pololu board for the extruder, techzone stepper for Z, and a Makerbot extruder board.

Microstepping with Pololu stepper boards on a Gen 3 motherboard



We have another machine using all other Makerbot boards with Pololu 1/16 step for X&Y, and this one has been tested, just need to finish hooking up the build plate power supply to start printing.



So as far as I can tell, you can pretty much mix and match just about any way you want. You just have to set the appropriate steps per millimeter for the Pololu's, depending on which setting you use on the individual boards.

In the beginning we weren't sure how much micro stepping the system would tolerate so we built jumpers into the Pololu boards to easily adjust. We found with the extruder, that it doesn't need to do any more than 1/2 stepping to run smoothly.
We originally tried micro stepping with the extruder ala Tony Buser because we were having so many problems with stepper stutter causing inconsistent flow of filament. Full micro stepping on the extruder was pretty neat, sounded like electronic music, but it caused lag in X and Y commands, so we cut the stepping back, to 1/8 then 1/4 then 1/2. Even at half stepping we had to double the steps in the firmware to get the same flow rate as running straight from the extruder board, so I assume the extruder board uses single stepping.

We started experimenting with Pololu boards for X & Y when we had an unsolvable stepper wandering problem with a set of techzone boards. Knowing that micro stepping the extruder caused lag, we built jumpers into the X & Y boards so we could easily adjust.



This time we started at 1/2 step and after listening to the very smooth Techzone boards. the Pololu boards made the machine sound, how do I put this, ANGRY. Like the motors movements were sharper or better defined. Made the machine much louder, even with the motors running at lower ambient temperature.
Anyway, we jumped the boards up to 1/4 stepping, and had no problems. So on we went to 1/8 and it started throwing communication errors. I remembered reading something about somebody experimenting with higher baud rates, but getting a little absent minded in my old age I couldn't remember where I read it. After Googling around for a while I found thisNightly Builds So we downloaded and uploaded and tried it again..... errors gone. So we went for the gusto. Full micro stepping...... Smooth as silk. Haven't had any problems since.

I sometimes run a machine in my basement right under my living room chair, that way I can watch some TV and keep a distant ear on the machine rattling away. I can't hear it anymore. I can't hear it in the next room any more. Nice, but a little unnerving at times.The machines run so much better now it's hard to describe.
I ran a couple Mendel circuit boards spacers as a test print at 80 mm/sec last weekend. It got a little grumbly around the holes but other than it ran smooth.

Guess that's all I've got
If you have any questions just ask

Bruce

Edited 1 time(s). Last edit at 12/19/2011 09:35PM by Bruce.