@ThantiK So, you have a problem with the DRV8825 being on board instead of on a module you could unplug from the board and replace. What if the chip itself was mounted on a DIP socket? Do you think it may be possible to convince the board makers to design the board with DIP sockets for parts the occasionally fail? They could even have clip on chip clamps to make sure they do not fall out, but could still be easily replaced. The heat sink could perhaps be part of that chip clamp.
@Brook_Drumm I see blown printrboards on Soliforum almost weekly. It seems silly not to make the drivers modular, especially with folks wanting to upgrade to 1/32 stepping, etc. It just doesn’t make sense, not when the board costs $100+ and making the drivers modular adds a couple bucks at most.
Also, it make sense to have separate drivers if you have a board with more than 4 driver positions, adding extra extruders or whatever can then be discressional as an option rather than having to fork out initially for something you may not use…
A big upside of on-board drivers is adjusting the driver current in firmware.
@Tim_Elmore The difference in small batches from Shenzhen can be more like a couple of bucks a driver position. For a small distributor adding $5 in the fab adds at least 10 to retail. You’re basically building two boards Though they are panelized it’s two board types, two flows, two tests, and a package each from the fab then the integration and assembly. If it’s integrated it’s one board, one pick, one flow one test one package. From a manufacturer standpoint you gain using an integrated driver but from a user standpoint there can be issues blowing driver. Many people though told not to hot patch motors still do.
Dave
Hi,
seems that you are interested in ARM board with stepstick/pololu drivers. I’ve already created smoothieboard clone with stepstick drivers. It´s in prototype stage, so please leave a comment if you like to add/modify something. I’ll be happy for any feedback. Here is the link for my blog http://base48.blogspot.cz/
I know most reprap users will not agree with me.
Blown drivers are a result of bad design (pololu drivers) or production. Shorts, Opens and disconnecting under power should not damage the drivers.Putting power on the stepper pins can damage the driver, but this is a very unlikely event.
ARM boards can improve the motion part of the printer, But the current ARM firmware does not improve it a lot. (TinyG does a much better job). For delta there can be a big improvement. But I do not see it in the current ARM firmwares.
A real USB connection is better compared to the USB - serial conversion on most avr boards. This improves the data throughput and limits the buffer empty problems. (This is also fixed by printing from SD card, Printing directly from a PC can give problems because it does not guarantee a stable data stream)
The stepper timing does not influence the print quality because its frequency is much higher then the resonance frequency of the mechanics.
The DUET may be quieter because it uses nopheads fix.
The azteeg x5 uses 1/32 steps.
When I was running a cheap board replacement, I got a bunch of knock off boards that had crappy build quality and low quality components. Open source board design can’t ensure quality work or components.
That aside, we will move to arm because it’s actually cheaper. Faster is good and I love future-proofing. I make the cheapest board possible for the task and will soon drop the price significantly. Adding hardware to make the chips replaceable just isn’t in the cards for our low cost goals. The high end boards are cool, I just think they will have trouble making a home in a typical home printer being manufactured in the thousands. Comparing specs sounds good on paper but brings very little right now in the real world.
What I really want is wifi and space to run software like octoprint. Faster on board slicing would be welcome and needs more processing power. Someday, I think USB will be dropped for wifi only. This will require an integrated computer, really. Linux, no doubt.
Running off topic. Sorry.
Brook
People are happy with AVR boards because they have limited their expectations based on what AVR chips can do. Firmware writers have pretty much maxed out the AVR, there is little room for improvement. ARM chips open up a whole lot of possibilities which could be “must have” features when users realise they can do them.
Drag and drop programming may not be 10x better than using the Arduino IDE, but it definitely is better and a step forward. It’s crazy to download the IDE and reprogram the firmware just to change the config, but that horrible workaround has become “normal”.
And the funny thing, ARM chips are 10x more powerful yet cheaper than AVR chips, which are way overpriced for 8 bits. That kinda blows out the cost argument.
I suspect there will never be a resolution to the integrated vs modular stepper driver debate: vive la difference! 
I do not say ARM is not the future. I think it is stupid to start new avr board designs. But the current firmware versions still use the motion system that is optimised for 8 bit systems (GRBL).
I have designed an ARM board more then 2 years ago. But have no time to finalise the firmware. I have it running with the marlin core and ethernet etc. But not finished. I also am working on reworking the motion core, this is a lot of work and need much testing.
USB should be dropped as fast as possible. Use ethernet/wifi and store the file on a sd-card. (Copy the file via ethernet/wifi to sd-card and start the print).
Yes, it’s firmware that holds the Arm back, not cost. Moving to arm will set the stage for future improvements and features-- and ease of use. We are doing rev f b/c we saw low hanging fruit for improvements. It will be our last 8bit board… Hopefully. Next will be arm and focussed on ease of use… It may drive cost up a bit but worth it if it’s easier to live with.
Just including @Riley_Porter_ril3y in this as he’s working on TinyG.
Give me an assembled BBB cape with 8 stepper drivers on for under 50 quid (85USD) and I’ll be sold.
Surely a Beefy ARM with pru’s for the real time bits gives us the best solution. Lots of Linux horsepower for slicing and calculations with the needed real time control and no crappy serial link.
The price of BBB isn’t far off the price of a licensed Arduino Due. If the cloners do the same for BBB, it would be much better value than Due. There is a small window where Cortex M3 boards could take off, but they may be quickly eclipsed by Linux boards. Again software is the key, but Linux is already there and EMC2 is nearly there. BBB is an attractive option already for more demanding deltas, just need some cheaper capes like CRAMPS.
@Brook_Drumm
Of course, closed source design doesn’t guarantee quality work or components either, and anyway that is not the purpose of Open Source, so your point is doubly irrelevant.
However, Open Source does guarantee that the user has full access to schematics, source code etc, the ability to create and share improvements, and allows competitors to create better/cheaper versions - unlike your Printrbot closed source model.
Four Freeedoms : http://www.ohanda.org/
@bob_cousins DO ABSOLUTELY WHAT EVER YOU WANT [with the design] [from http://ohanda.org] is not a requirement for open-source, it’s the definition of public domain. Some organizations do exclude non-commercial licenses from their definition of open-source, but as far as i’m concerned, Printrbot’s hardware is open enough. And i mean, if you do want to screw over @Brook_Drumm , just buy a non-licensed printrboard clone: http://www.aliexpress.com/wholesale?SearchText=printrboard
ALL OPEN SOURCE ORGANIZATIONS EXCLUDE NON-COMMERCIAL LICENSES from their definition of Open Source, without exception. (Sorry I can do shouty but don’t know how to fancy italics). The OHANDA guidelines are little mis-worded, but the principles still hold.
I realize that Brook is a demi-god around here, and I am just a humble non-business owning Open Source developer, but there is so much bullshit spoken about Open Source it needs to be challenged!
It is very ironic that the About box starts with “A community centered around open-source…” yet the group owners don’t seem to understand what Open Source means!
Look, if someone says “we’re not an Open Source company, and we do not sell Open Source products” then fine, I won’t ever mention OS. I really don’t care about Brook Drumm’s proprietary products, I’ll never be buying one of his designs, official or clone, although he seems to be saying the same things Bre Pettis said.
If Brook hadn’t decided to have a little dig at Open Source which he so dislikes, I wouldn’t have said anything.
But PLEASE, can we cut the FUD, disinformation and outright lies about Open Source? If you don’t believe in supporting Open Source, fine, but take it out of your About box.
There are plenty of other places to learn about Open Source, e.g. http://opensourceecology.org/wiki/4_freedoms http://www.oshwa.org/definition/ http://opensource.org/osd
Open Source is actually a well defined thing, although the people who dislike Open Source or plain couldn’t be bothered to find out would have you believe it is just some fuzzy thing that means whatever is convenient for them.
Actually the OHANDA guideline is correct, “use for any purpose” is not the same as Public Domain. In Open Source the author retains authorship rights, PD means all rights are waived or expired. These sort of questions are easily answered if you look on the web. http://opensource.org/faq
@bob_cousins You love to yell about opensource not being opensource. What projects have you opensourced?
Do you make a living off of it?
Are they popular?
If the answer is no to any of these questions, back off until you make your mark.
The printrboard is completely open source. Completely. The PrintrBot original is too. The lasercut designs are all moving to CC attribution share and share alike. The metal simple wont be open until we update it at some point. I love open source and don’t mind the dig. Those that know my company and me know what’s up. I employ people to build on open source projects and openly share with the community. I’ll keep doing it. While not everything I release grows and helps the company, some does, but I don’t do it for money. I do it cause I love it and love the community and what’s happening on the 3d printing space. Not everyone believes my stated values, but that’s ok by me.
Brook