Low cost 32-bit controller board February 20, 2015 07:12AM |
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Re: Low cost 32-bit controller board February 20, 2015 11:02AM |
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Re: Low cost 32-bit controller board February 20, 2015 11:15AM |
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Re: Low cost 32-bit controller board February 20, 2015 11:47AM |
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Re: Low cost 32-bit controller board February 20, 2015 11:51AM |
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Re: Low cost 32-bit controller board February 20, 2015 01:09PM |
Registered: 11 years ago Posts: 869 |
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dc42
* Two Z motor connectors to make it easy to connect two motors in series.
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* One heated bed output, rated at 20A.
* Two hot end heater outputs rated at 10A.
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Two outputs for 12V fans etc., one with PWM, the other without.
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* Three endstop inputs
* Three thermistor inputs
* A 4-pin connector for supporting several different kinds of Z probe.
Re: Low cost 32-bit controller board February 20, 2015 01:41PM |
Registered: 11 years ago Posts: 14,685 |
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dougal1957
I think you could be on to a winner with this idea especially if you can get the price break to be similar to that of a Mega + Ramps combo and that seems to be around the £25-30 mark (suspect this may be the stumbling block).
Re: Low cost 32-bit controller board February 20, 2015 03:03PM |
Registered: 10 years ago Posts: 569 |
Re: Low cost 32-bit controller board February 20, 2015 04:53PM |
Registered: 11 years ago Posts: 14,685 |
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Kurzaa
What would be the price difference between two hotends vs a single hotend?
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Kurzaa
Also, I only skimmed the list, but don't forget pins for fans, servos, and LEDs. Probably my biggest gripe with my current RAMPs board.
Re: Low cost 32-bit controller board February 21, 2015 10:06AM |
Registered: 14 years ago Posts: 7,616 |
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: Low cost 32-bit controller board February 21, 2015 11:07AM |
Registered: 11 years ago Posts: 14,685 |
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Traumflug
Like @Kurzaa I think you're already pretty high on the feature list for a low end board. Not much more and you can simply copy the Duet.
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Traumflug
A few words about what I observed about people's recognition over the years:
If you also offer a StepStick derivate with digital current control, people will likely recognize these derivates are required. The fact that Gen7 Opto Endstops exist makes most people thinking Gen7 requires Opto Endstops. Of course it doesn't, mechanical endstops work just as fine as on any other controller. With this in mind I'd stick to the pure Pololu form factor for the stepper drivers which is pretty much an industry standard now.
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Traumflug
Visual appearance is more important than technical facts. These large silkscreen logos on the back or similar. 4pi is recognized as "the controller with an entirely flat back". RepRapDiscount makes all its boards white (second silkscreen covering the whole board), for a more friendly appearance. Asking a friend with an artistic mind to put something nice, unique onto the board is likely a good idea.
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Traumflug
From the Open Source perspective: doing the design in gEDA or KiCAD would be awesome. Both are entirely sufficient for such tasks and KiCAD is currently on a steep rise: [reprap.org]
Re: Low cost 32-bit controller board February 21, 2015 12:35PM |
Registered: 10 years ago Posts: 1,159 |
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dc42
I'm in favour of using open source tools as long as they are up to the job, so I started doing a board layout for this in KiCad. But I quickly found that none of the major SMD components or even most of the connectors I need are in the KiCad library, or any other libraries for Kicad that I could find. I don't have time to design them all. So unless someone can point me to KiCad libraries for these parts that I failed to find myself, or an Eagle to KiCad library converter, I will carry on using Eagle. But I'm keeping the size to within the 100x80mm size limit of the version that is free for individuals to use. It's a great pity that there is no universal XML format to describe components to PCB layout programs, if there were then the component manufacturers might produce these files themselves.
Re: Low cost 32-bit controller board February 21, 2015 04:46PM |
Registered: 11 years ago Posts: 14,685 |
Re: Low cost 32-bit controller board February 21, 2015 06:57PM |
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Re: Low cost 32-bit controller board February 21, 2015 07:07PM |
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Re: Low cost 32-bit controller board February 21, 2015 08:08PM |
Registered: 14 years ago Posts: 7,616 |
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JamesP166
I am an electronics engineer and do my own board layouts with Altium - - - a bit more than an open source or free tools. but the cost is worth it for the power and performance and the libraries
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: Low cost 32-bit controller board February 21, 2015 10:29PM |
Registered: 10 years ago Posts: 977 |
Re: Low cost 32-bit controller board February 22, 2015 12:50AM |
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Re: Low cost 32-bit controller board February 22, 2015 04:59AM |
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Re: Low cost 32-bit controller board February 22, 2015 06:53AM |
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dc42
Having the web interface built in means that it can provide information that is not available via gcodes, and continue to provide real time information when the printer is executing commands that take a long time to complete.
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dc42
Eclipse is the obvious choice for open source firmware.
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: Low cost 32-bit controller board February 22, 2015 02:16PM |
Registered: 10 years ago Posts: 977 |
I confess I never actually used Pronterface, as I had an OctoPrint RPi box up and running before my first 3D printer was even fully operational.Quote
dc42
Thanks for the additional comments.
Regarding Ethernet support and a web interface, the Duet electronics and firmware provides an excellent web interface at the same time as running the printer, all on a 84MHz Cortex M3 processor with 96K RAM. The benefit is huge IMO. Once you have used the web interface, you never want to go back to Pronterface.
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Re: Low cost 32-bit controller board February 22, 2015 02:42PM |
Registered: 11 years ago Posts: 14,685 |
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AndrewBCN
The big hurdle I see for this new project is that basically it offers almost the same feature set as a Duet board (except for the fact that the Duet includes 4 Allegro A4982 steppers drivers soldered in), and yet one of its objectives is to reach a manufacturing cost similar to that of an Arduino Mega 2560 + RAMPS combo, something I would deem is very difficult if not impossible.
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AndrewBCN
Wouldn't it be a lot faster to develop, simpler, cheaper and more effective to just move the heavy duty processing to the Linux box and leave only the nitty-gritty realtime pulse generation and sensor reading to the Mega 2560?
Re: Low cost 32-bit controller board February 22, 2015 06:03PM |
Registered: 10 years ago Posts: 977 |
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dc42
...
The board I propose will also cost less to manufacture than a Duet, mostly by using a microcontroller with fewer pins and without on-chip Ethernet, leaving off the other Ethernet bits...
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dc42
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I'd be reluctant to move anything to a Linux box, because I like the fact that both my Duet-powered printers are ready to be controlled within a second of being powered up.
Re: Low cost 32-bit controller board February 22, 2015 07:07PM |
Registered: 11 years ago Posts: 14,685 |
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AndrewBCN
Just two posts above you argued in favor of including an Ethernet interface and now you are arguing that to save costs this same Ethernet interface should not be included in your new design?
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The small ARM boxes I use as Linux Debian / OctoPrint servers stay on 24/7, their power consumption being approximately the same as the standby power consumption of the ATX PSUs I use for my 3D printers (i.e 2.5W), so as far as "readyness to print after power on" is concerned, they are a non-issue
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So far it seems to me that you are planning your new design basically by making small changes to the Duet design, what I am proposing is to think outside the box and do something different.
Re: Low cost 32-bit controller board February 22, 2015 07:55PM |
Registered: 10 years ago Posts: 977 |
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dc42
Andrew, thanks for your thoughts.
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AndrewBCN
Just two posts above you argued in favor of including an Ethernet interface and now you are arguing that to save costs this same Ethernet interface should not be included in your new design?
Read the whole thread. I have always said that this board will not have Ethernet. But I posed the question, will that limit sales of the board too much, because I suspect that Ethernet will in time become a must-have feature.
Re: Low cost 32-bit controller board February 23, 2015 03:41AM |
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Re: Low cost 32-bit controller board February 23, 2015 05:14AM |
Registered: 10 years ago Posts: 100 |
Re: Low cost 32-bit controller board February 23, 2015 05:33AM |
Registered: 11 years ago Posts: 14,685 |
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plankton
@dc42
Good luck with this, a low cost viable alternative to RAMPS/Mega is long overdue (before anyone says anything, I know there are lots of alternatives already out there, but none have yet had the right combination of price and features to wean the majority of users away from RAMPS - which this project sounds like it could), my only request on the hardware would be to use screw terminals or friction fit (not ordinary pcb headers) for the main connections like stepper motors, endstops, and thermistors (as well as power, heatbed, and extruder(s)). If that is not possible then consider leaving room for people to solder whatever type of connector they want.
+1 for a pin for ATX power standby
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plankton
The biggest stumbling block I see to take up will be firmware, unless this can run a straight port of firmware from another board then you will not get large scale take up until people see it can match the features and performance of the likes of Marlin. Also the clone makers probably won't pick it up until they see viable firmware. Is your plan to develop new FW from scratch, or will this be based on an existing FW?
Re: Low cost 32-bit controller board February 23, 2015 07:48AM |
Registered: 10 years ago Posts: 100 |
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dc42
Screw terminals are nice for anyone who designs and builds a printer from scratch and doesn't want to pay £20 or so for for a crimp tool.
Re: Low cost 32-bit controller board February 23, 2015 07:48AM |
Registered: 10 years ago Posts: 977 |
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plankton
I think we can probably all agree that some form of network connectivity is a desirable feature, however if it will add significantly to the projected cost then that will defeat the intended purpose of this board (and Octo-Print is certainly a good solution for anyone that needs a Web interface).
@AndrewBCN
You make a good point that the software toolchain could be redesigned to remove more of the heavy lifting from the printer electronics (as has been discussed before on this forum), and that in turn could allow a rethink of the printer electronics, however that is a much bigger project than "just" producing a 32 bit RAMPS/Mega replacement.
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Tim