BNC sigma just released all the fies for there sigmax (Dual independant head}
And the folds at e3d are developing a 4 head tool change system.
And iirc the folks at ultimaker still have source files for there machines available.
you may want to take a look at this technology as well.

This is the beauty of open source you can improve on others work legally and help everyone in the process.

Whatever you decide have fun this is a hobby.

If you want to design a board go for it . IMHO there is plenty of room for innovation. Just make sure you are making measurable improvements . This is a hobby how you go about it is your business. 
And do not take carl wrong he is just citing previous work  and trying to lead you away from pitfalls and redundancy.

Sure, I get it. I just thought I was quite clear on my exact reasons for my project being intentionally different from what is already out there. You know how the veterans like to chide the noobs with "read the whole thread". Well...

Might be true, but I am pretty sure there are user doing ABS. Most people who buy these junk piles and decide to keep them usually print a new extruder and install a better hotend first thing. The stock hotends have a very well known history of constant jams. So you would most likely need to swap out your hotend as well in your project to be as fully functional as you want. Otherwise there is no real meaning to making an open source board since you would still be limited by the hotend.

I see no reference to anyone printing ABS on a Mini. The firmware limits the extruder temp to 200°C +/- 10°C. Is there a web page referencing someone 3D printing an improved extruder the Da Vinci Mini? I used to think my Hot End was jamming too, then I learned about Z-height adjustment. No problems with that now. My printer did have an issue with the filament drivers overheating causing the feed motor to not run at all partway into a print, but guess what? That's a board issue! There's a whole thread on this forum relating to porting Repetier or Marlin over to the JR. How is what I'm not doing better than that? In both cases you'd have a clean hardware solution but in my case, there will be much better hardware under the hood. This in turn will allow for better firmware to be written and developed, not just ported.

Also, is no one reading my motivations? I want to learn about 3D printing by doing the hardware from scratch. That is the meaning for me. Just because you personally and others have no interest in my project, because you clearly do not have a Mini, does not make my project meaningless. I'm betting there are Mini owners who will appreciate what I'm doing, but that's not a requirement, just a perk. The Mini is not as junky as people might think, it's just poor implementation. I'm starting to gather that the Mini might be made with better parts than the JR. Maybe the JR jambs all the time, you can't automatically say the Mini does the same. The Mini has a 24V head while the JR has a 12V head. The engineer in me says that's better. Not because 24 > 12, but because at 24V it takes half the current to push the same amount of power. I'm going to suggest that of all the $200 platforms, I've chosen perhaps the best one to make my project. It's one thing to know how to hack something and write up instructions, it's another to understand precisely how and why something works. You cannot innovate if you don't know PRECISELY how the thing works, you can only copy and be another "me too" PCB hack. If I don't see the potential for innovation, then there would be no little point in my project. For people who claim "There's nothing left to innovate here, it's all been done." I say that's the difference between a hacker and an innovator. ;P

carl_m1968 wrote:

The_Extruder wrote:

You may want to re-read my stated motivations. In the end, I'll have made a better Mini; it won't look like a hack job; other Mini owners will easily be able to install it, and I'll learn a ton about how a 3D printer works in the process. If I wasn't motivated by the sum total of those goals, I'd just go buy one of the existing hacks.

The minimover APP is nothing but an APP for your phone that allows you to buy blank NFC tags and program them with your desired settings and filament type. You then place it over the tag reader in the machine in place of the one on the spool. Then use the filament of your choice. There is no modification to the machine, no change in appearance or function or program. Just giving it a different tag to read.

Ah, but I thought the Mini(And, perhaps JR) was(were) incapable of printing ABS because you could not command the extruder to print at ABS temperatures. Is that not true?

Might be true, but I am pretty sure there are user doing ABS. Most people who buy these junk piles and decide to keep them usually print a new extruder and install a better hotend first thing. The stock hotends have a very well known history of constant jams. So you would most likely need to swap out your hotend as well in your project to be as fully functional as you want. Otherwise there is no real meaning to making an open source board since you would still be limited by the hotend.

The_Extruder wrote:

carl_m1968 wrote:

The minimover app lets you set the machine to do PLA, ABS, and PETG. So again you technically are late to the game. All you are doing is just basically making an enclosed 32 bit machine such as my CT'c and the Azteeg X5.

You may want to re-read my stated motivations. In the end, I'll have made a better Mini; it won't look like a hack job; other Mini owners will easily be able to install it, and I'll learn a ton about how a 3D printer works in the process. If I wasn't motivated by the sum total of those goals, I'd just go buy one of the existing hacks.

The minimover APP is nothing but an APP for your phone that allows you to buy blank NFC tags and program them with your desired settings and filament type. You then place it over the tag reader in the machine in place of the one on the spool. Then use the filament of your choice. There is no modification to the machine, no change in appearance or function or program. Just giving it a different tag to read.

Ah, but I thought the Mini(And, perhaps JR) was(were) incapable of printing ABS because you could not command the extruder to print at ABS temperatures. Is that not true?

carl_m1968 wrote:

The minimover app lets you set the machine to do PLA, ABS, and PETG. So again you technically are late to the game. All you are doing is just basically making an enclosed 32 bit machine such as my CT'c and the Azteeg X5.

You may want to re-read my stated motivations. In the end, I'll have made a better Mini; it won't look like a hack job; other Mini owners will easily be able to install it, and I'll learn a ton about how a 3D printer works in the process. If I wasn't motivated by the sum total of those goals, I'd just go buy one of the existing hacks.

The minimover APP is nothing but an APP for your phone that allows you to buy blank NFC tags and program them with your desired settings and filament type. You then place it over the tag reader in the machine in place of the one on the spool. Then use the filament of your choice. There is no modification to the machine, no change in appearance or function or program. Just giving it a different tag to read.

IMHO if you are going to reinvent the the main board make it universal like the arduino Ramps so it can work  on any 3d printer.  I understand folks will have to work with the physical format a bit but we already have to do that with the ramps.

Marlin is already 32 bit comparable then  i is a matter of tweaking Marlin or repitier for the most popular printers. 
If i was developing a new board I woul make sure it is compatable with trinamic drives  they seem to be one of the up and coming technologies.

If you are anywhere close to Bel Air Md, come out to EERF and see what much of the rest of the world  is doing   http://eastcoastreprapfestival.com/

Well, the first one I make is going to be exactly what I want. If I have luck with it, I can respin it for other printers or make a universal one. It would just be a layout change and possibly some resistor options for extruder voltage and current settings. I'll check out the Trinamic driver chips, but I'll be checking out all of the options available. These QFN motor drivers are new to me. The one's I'm used to using are HTSSOP with big pins and a slug on the bottom. That was for non-stepper BLDC's though with a stall current at 4.0A.

I'm on the wrong coast for EERF, but I'm actually not diving full in to 3D printing at this stage. This just one of many, varied, projects I'm working on.

Marlin is already 32 bit comparable then  i is a matter of tweaking Marlin or repitier for the most popular printers. 
If i was developing a new board I woul make sure it is compatable with trinamic drives  they seem to be one of the up and coming technologies.

If you are anywhere close to Bel Air Md, come out to EERF and see what much of the rest of the world  is doing   http://eastcoastreprapfestival.com/

The minimover app lets you set the machine to do PLA, ABS, and PETG. So again you technically are late to the game. All you are doing is just basically making an enclosed 32 bit machine such as my CT'c and the Azteeg X5.

You may want to re-read my stated motivations. In the end, I'll have made a better Mini; it won't look like a hack job; other Mini owners will easily be able to install it, and I'll learn a ton about how a 3D printer works in the process. If I wasn't motivated by the sum total of those goals, I'd just go buy one of the existing hacks.

carl_m1968 wrote:

Lot of work considering there already is an easy to use Java based program to program and use your own blank NFC213 tags and third party filament.

This is not just about the tags. I like to make stuff! Also, I may learn something about the extruder during my experimentation that suggests we could also use ABS with this printer. Impossible with the existing hardware or at least firmware platform. Maybe not a limitation of the extruder with the proper driving hardware? Perhaps. Once I learn the pinout of the extruder, I may make a standalone test fixture where I can dial in the temperature and push different filament through it. Also, I could do some "burn-in"(Ha, a pun!) longevity testing as well.

The minimover app lets you set the machine to do PLA, ABS, and PETG. So again you technically are late to the game. All you are doing is just basically making an enclosed 32 bit machine such as my CT'c and the Azteeg X5.

Lot of work considering there already is an easy to use Java based program to program and use your own blank NFC213 tags and third party filament.

This is not just about the tags. I like to make stuff! Also, I may learn something about the extruder during my experimentation that suggests we could also use ABS with this printer. Impossible with the existing hardware or at least firmware platform. Maybe not a limitation of the extruder with the proper driving hardware? Perhaps. Once I learn the pinout of the extruder, I may make a standalone test fixture where I can dial in the temperature and push different filament through it. Also, I could do some "burn-in"(Ha, a pun!) longevity testing as well.

IMHO reinventing the wheel or in this case a control board is not necessary the best path. .

Oh, I'm actually not attempting to re-invent. I'm attempting to innovate and make something that is less Hack and more drop in improvement. I start in a virtual vacuum so my thoughts are not steered intentionally toward what has already been done. Also, as many 3rd rate 3D printer companies have proven, when you just copy another product without fully understanding the nuances(control systems, fluid dynamics), you end up making and selling a product you don't understand, and no surprise, it ends up being considered "crap".

Atmel 8-bit processor based? No thanks. Also, why would I want to be just another tutorial writer that shows you how to wire up rats nest? Again, I don't know the full specifics or capabilities of the ramps based hardware, but with an 8-bit MCU, I'm suspecting you can't just dump a job onto it and have it print. It's likely getting spoon fed instructions from the host. Again, I could be wrong and I don't even want to know as I want to embark on this with no preconceptions. Otherwise, I'm just copying, not innovating. That's the real goal for me. I'm suddenly curious about 3D printer technology and precisely how it works. What better way to learn than by making a platform. Since mechanical fabrication and ID are actually costly, why not use this cheap, troublesome-for-many, Mini and use it as a starting point? The people wth those machines, I'm sure would love to have a drop in board and not have to hack together a rats nest of harnesses. A solution for non-hackers if you will.

Never said I wanted to sell firmware. I would only sell the hardware. But I may develop my own set of APIs as well for myself or anyone else who may have innovative ideas they want to test out that don't fit in with the existing open source firmware platforms. Any engineer knows that there are potentially hundreds of ways to solve the same problem. I'm assuming we may not yet have found the best one for cartesian based 3D printing

Hence the drop in board. No rebuilding required. As far as cost, I'm hesitant to speculate this early in the project, but It will definitely not cost near as much as a new Mini. It will likely coat more than a Ramps + 4 Polulus, but should be competitive given the hardware features it will include.

Thanks , although it will take more time than luck, in this case. I kind of already have the hardware architected in my head...