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Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Tue Jun 27, 2017 9:25 pm
by slippyr4
LATEST VERSION IS V3.1.0 - CHANGE TO THE 3.1.0 BRANCH IN GITHUB


Those that have build a clone prusa i3 MK2 (perhaps a dolly, or similar) that have bought one of the now available clone MK42 beds might be interested in running stock prusa firmware.

The original firmware is setup for the mini rambo- ramps uses different pins and doesn't have digipots for stepper current. That means that the "quiet mode" vs "power mode" won't work at all.

I've put the work in to port v3.0.11 over so that it works with standard RAMPS pinout. That means it works with RAMPS and other hardware that copies RAMPS like MKS BASE, MKS GEN etc.

The MKS boards are a better bet because they have an extra output mosfet which is used to drive the extruder fan; if you use a real RAMPS you'll have to just hardwire that to the supply.

Get the firmware from https://github.com/slippyr4/Prusa-Firmware

Clone the repository, open it in arduino ide and upload the sketch to your prusa clone. If you've built your clone properly and have a MK42 it should pass calibration ok.

I shall aim to keep it up to date - the latest prusa firmware is an RC that merely adds support for the multi material upgrade which I don't have, so i've not merged those changes yet. I'll wait for a non-RC release.
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Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Tue Jun 27, 2017 9:26 pm
by slippyr4
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(a bit overextruded, I know. but thats the supplied gcode, not resliced)

Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Tue Jun 27, 2017 10:34 pm
by chumm
This is awesome, thanks! How are you finding your clone MK42 (and which did you buy?)

Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Wed Jun 28, 2017 11:36 am
by slippyr4
chumm wrote:
Tue Jun 27, 2017 10:34 pm
This is awesome, thanks! How are you finding your clone MK42 (and which did you buy?)
I have two actually, one from each of the two indigogo campaigns. One of them is too warped to use, and the other one seems pretty good. I'm certainly impressed with PEI as a print surface.

Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Fri Jun 30, 2017 1:09 pm
by hendrik
Hi, would you mind to hint which seller had the non warped version? :)

BTW: There are some people eager to have this firmware in the prusa forums: http://shop.prusa3d.com/forum/english-forum-f4

Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Fri Jun 30, 2017 1:29 pm
by slippyr4
I know, but you can't post in those forums if you're not a prusa customer!!

The autotronix board is the better board.

Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Fri Jun 30, 2017 4:56 pm
by hendrik
slippyr4 wrote:
Fri Jun 30, 2017 1:29 pm
I know, but you can't post in those forums if you're not a prusa customer!!
I didn't know - I though I registered before buying a Prusa .. but I'm not sure anymore.
slippyr4 wrote:
Fri Jun 30, 2017 1:29 pm
The autotronix board is the better board.
Hey thanks a lot!

Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Sun Jul 23, 2017 12:14 pm
by slippyr4
I've now updated the firmware on github to 3.0.12

No multimaterial support at the moment. I will look into that in the future, but so far the electronics for the extruder multiplexer board isn't publically available and that makes it more trouble than it's worth to try and implement that on a clone.

Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Sat Aug 12, 2017 11:59 pm
by IanC
Fantastic work, I'll be trying out this firmware on my MKS Gen shortly.

I just had a quick question, as this is my first time using print controller boards like this. Do I need to get a separate MOSFET expansion board to use the MK42 heatbed with the MKS Gen 1.4? I have heard some people say that the screw terminals can't handle the current for the MK42 heated bed and that I'd need to use a separate MOSFET board anyway.

How did you adjust the current of the steppers, did you just measure across the pots to match the values from the Prusa firmware?

Re: Prusa firmware for RAMPS Prusa i3 clones with MK42 beds

Posted: Sun Aug 13, 2017 9:05 am
by slippyr4
I've not had a problem with the connectors, and the mosfet itself can cope. Make sure you strip the wire well and I'd tin the ends with solder to get the best contact possible.

You need to match the current to the steppers - if you suppply more current than a stepper is rated for it will get very very hot and possibly meet an untimely end. Google your stepper motors to find out what their max current is and then set the Vref accordingly. What you set it to varies depending. In what driver you're using; there's a http://reprap.org/wiki/Pololu_stepper_driver_boarduseful page on reprap.org which tells you what to do.