Raspberry PI vs. Panelolu2 for stand-alone use?

I finally have most of the parts that I need to build my Mendel90, with the exception of the MDF - I just got my hardware kit and other assorted parts from Nophead in today's mail, along with my EBay "Elecfreaks" Melzi board (having a problem getting Arduino to compile, though, so I can update my firmware to Nophead's Marlin fork...keeps saying something about "undefined reference to setup" and "undefined reference to loop").

Anyway, I would eventually like to set my machine up to run without having to be hooked up to my ancient and tempermental laptop running Windows Vista (be my luck it would hiccup in the middle of a print). I don't have any prior experience with 3D printers, or their software (I'm used to programming G-code for Haas CNC mills at work, but that's about it). I have heard about people using a Raspberry PI (which looks like a neat gadget but I don't know much about it) or a Panelolu2 with a Melzi interface for independent operation. Which would likely be the better, less headache-prone option for me? Or is there a better one than either of those (that does not involve buying a new laptop or a different controller board, that is)?

I have both.

The Panelolu2 is great for showing me what's going on and running simple operations (jogging the axes around, setting temperatures, swapping filaments etc) and the in-built card reader makes it easy to start jobs from an SD card. I still need to move the SD card between my laptop/desktop/slicing machine and my Panelolu2, but for things where I might print multiples or repeat the job at a later date it makes things very easy. There's also a handy/easy-to-reach-in-a-panic reset switch that stops everything immediately - if, for example, I find my hotend dropping down onto my bed blanket because I forgot to remove it after my pre-heat phase...

Running OctoPrint on a Raspberry Pi (there's a ready-to-go distribution called OctoPi) gives me a network print server right there on my Mendel90. I can access the web GUI from anywhere in the house (or the web if I punch a hole through the firewall) and from which I can upload jobs, start/pause/cancel them, monitor my extruder/bed temps (with graphs!), preview the gcode paths and even watch a live webcam feed from the camera that I have installed (I use a Logitech C270 but the PiCam is now available in a much smaller package).

Both options are easy enough to setup - they're not something I would trust my mother to setup but if you manage to build and calibrate your printer then you'll be fine following the well documented instructions for configuring these.

quaking plums has hit the nail on the heat. The Panelolu2 is there as a hands on control, where as the more remote webs based options usch as octoprint have a lot more features but you are then fishing for a phone/tablet/pc to use them.

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DuetWifi.: advanced 3d printing electronics

Okay, so is there a good, cheap, and easy to set up system that will allow me to run my printer 100% independently ( not counting using a seperate computer for slicing and burning g-code on SD cards), without needing wi-fi or Bluetooth capability or
access?

Quote
Rich K.
Okay, so is there a good, cheap, and easy to set up system that will allow me to run my printer 100% independently ( not counting using a seperate computer for slicing and burning g-code on SD cards), without needing wi-fi or Bluetooth capability or
access?

Exactly what the Panelolu2 was designed for.

"good" - Yes, it works, does what it says in the product description.
"cheap" - All depends on what you compare it to but yes!
"easy to set up" - Needs you to upload different firmware, to do some wiring and to print out a housing/case to hold the electronics


I have a similar set up to Quackingplums which, as said, gives the best of both worlds - totally independent printing using the P2 which allows me to print from the SD card AND control via the Octopi web interface. The OctoPi system allows you to drag and drop GCode files directly to the Raspberry Pi and print via its USB interface too which is handy from time to time.

Even if I print using Octopi, I can also adjust parameters via the P2 as the print progresses if needs be. Increasing or decreasing speed for example involves a simple twiddle of the rotary controller - effectively an M220 Snn command on the fly.

Alan

Edited 3 time(s). Last edit at 10/02/2014 02:18AM by Alzibiff.

So in other words, I would not be able to use Nophead's fork for Marlin with that setup?

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Rich K.
So in other words, I would not be able to use Nophead's fork for Marlin with that setup?

Correct - you would need to make changes as described in the Think3DPrint3D blog effectively extending Nophead's fork of Marlin to include the LCD support files, NeilDarlow has done a lot of work in this area, have a read through this thread [forums.reprap.org]

Alan

Edited 1 time(s). Last edit at 10/02/2014 04:50AM by Alzibiff.

I can't remember if later kits came with a revised firmware that supports the P2, but forum user neildarlow maintains a fork here that incorporates the Nophead's changes and P2 support into the latest Marlin build.

EDIT: haha Alan beat me to it!

Edited 1 time(s). Last edit at 10/02/2014 04:45AM by QuackingPlums.

Now, can I use that particular firmware upgrade with my laptop, BEFORE I get a P2 or a R-PI? Or should I stick with Nophead's version until I am ready to upgrade the system?

Hi,

The firmware can be used without a Panelolu2 connected. In fact I had to expend considerable effort to permit that.

Panelolu2 and EEPROM settings support are enabled but will not interfere with normal operation of the firmware. The only difference is that I use Z_HEIGHT_MM where nophead uses Z_HOME_POS but the two essential settings are placed at the top of Configuration.h.

If you want to use the Heated Bed PID temperature control feature it has to be enabled manually because it is necessary to run a PID Auto-tune cycle. I was not going to make assumptions about what type of glass people print on so you need to determine the PID constants yourself.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Quote
Rich K.
Now, can I use that particular firmware upgrade with my laptop, BEFORE I get a P2 or a R-PI? Or should I stick with Nophead's version until I am ready to upgrade the system?

One of the changes which NeilDarlow has implemented in his version of the firmware is to enable the M90 to work with or without the P2 attached which was not the case with the T3DP3D firmware which, as described in the blog, "hangs" if a P2 board is not plugged in. So .... the answer to the question is "Yes".

As the RPi simply replaces a PC / MAC / Laptop and plugs into the USB port on the MELZI there are no worries there either.

Alan

Edited 1 time(s). Last edit at 10/03/2014 02:40AM by Alzibiff.

Quote
neildarlow

If you want to use the Heated Bed PID temperature control feature it has to be enabled manually because it is necessary to run a PID Auto-tune cycle. I was not going to make assumptions about what type of glass people print on so you need to determine the PID constants yourself.

Regards,
Neil Darlow

Sorry, but what exactly is PID? I will be using 3mm borosilicate glass to cover the bed, BTW.

P.I.D. is a temperature control scheme that employs three elements of feedback i.e. Proportional, Integral and Derivative.

The Proportional term controls the magnitude of output change for a given error between the set and measured temperature. The Integral term acts to reduce the steady state error to a minimum. The Derivative term defines the output change in response to a rapid change of input (set temperature vs. measured temperature).

For any closed-loop control system (which our extruder and heated bed are) there is one combination of P, I and D which produces a critically-damped response. This is where the measured temperature achieves the set temperature quickly with a tiny amount of overshoot and undershoot at the set temperature followed by maintaining the set temperature with minimal offset error.

Marlin can attempt to determine P, I and D values by performing one, or more, temperature cycles and prints out the values Kp, Ki and Kd for you to insert into the firmware for your particular setup.

Regards,
Neil Darlow

Edited 2 time(s). Last edit at 10/03/2014 10:01AM by neildarlow.

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Okay, I just ordered a P2 from T3dP3D today. I want to get a R-PI next, but from what little I know about the device, it basically comes as just a computer module with nothing attached. What add-ons will I need to get along with the basic R-PI to use it with the Melzi and P2? Also, can I power the R-PI from the same power suppply as the Melzi and P2? I'm using a 600 watt ATX power supply.

Quote
Rich K.
What add-ons will I need to get along with the basic R-PI to use it with the Melzi and P2?

A USB cable to connect the RPi to the MELZI. You will also need some way of connecting the Pi to your home network - either an ethernet cable if you are going to hard wire it or a USB WiFi dongle.

Quote

Also, can I power the R-PI from the same power suppply as the Melzi and P2? I'm using a 600 watt ATX power supply.

Yes. Wiring the PSU to the Pi is probably the hardest bit as the power connector on the Pi uses micro USB. Best plan is to get a good quality micro USB cable and cut it off close to the micro USB plug in order to strip back the two wires which you can then connect to a +5V line and GND on the PSU. A good starting point is to read Nophead's blog post here: [hydraraptor.blogspot.co.uk]

Alan

Edited 3 time(s). Last edit at 10/04/2014 06:26AM by Alzibiff.

Quote
Alzibiff
A USB cable to connect the RPi to the MELZI. You will also need some way of connecting the Pi to your home network - either an ethernet cable if you are going to hard wire it or a USB WiFi dongle.

Alan

I found a used R-Pi model B and a 3.2" touch-screen for a total of about $60 (the Pi, with a case, was $30). I wanted the touch screen so I would have a graphic interface with the Pi.

Nop Head says the Pi may be capable of doing its own slicing, though it would probably be slow. If that's true, then I really could go completely independent of another computer.

I was actually looking to run the printer without having to connect to my home network - the idea being to make the printer more transportable and useable in case I want to take it somewhere WITHOUT wi-fi or other networking, and don't want to tie up my only "full-featured" computer.

Quote
Rich K.
I was actually looking to run the printer without having to connect to my home network - the idea being to make the printer more transportable and useable in case I want to take it somewhere WITHOUT wi-fi or other networking, and don't want to tie up my only "full-featured" computer.

Which is where the Panelolu2 comes in! Adding the Pi as well gets you the best of both worlds IMHO!

Alan

Just finished modding my PSU. Had a scare because it doesn't have a "3.3v sense" wire at all (20-24 ATX connectors apparently don't always have them), but Nop Head says just ignore that part of the instructions in my case. One wire my PSU DOES have is a white "-5v" wire. I know the purple "+5v Standby" wire is what Nop Head used for the +5v for his Raspberry Pi. Could I use the white "-5v" wire for the negative lead? Or am I better off hooking up the negative to the ground terminal of one of the limit switches on the Melzi board, like Nop Head did?

Okay, Chris says "NO!!!" to using the - 5 v wire, as it would create 10v.

Here's another question: my 'Pi does not have wi-fi capability, and I don't have an ethernet hub to directly connect to. I want to run Pronterface/Printrun on it as my controller software (not really interested in Octo-Pi/Octoprint, since if I understand it correctly all it does is turn the 'Pi into a sort of network "relay" to remote-control the printer from another computer, and that is NOT what I want to do - I am looking for 100% network-free independent operation). Is there a way to install the software directly onto my SD card (which is 16gb) and get it to work without a whole lot of hassle?

Edited 1 time(s). Last edit at 10/13/2014 05:59PM by Rich K..

So, you are intending to use the Pi as a computer with a connected keyboard and display?

The Pi will be running some flavour of Linux (Raspian, a Debian derivative, is the standard choice I believe). In that case you should be able to install Pronterface, and its dependencies, from the distribution's official repositories.

I can't help thinking that for truly standalone, minimally encumbered, operation the Panelolu2 might be your best option.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Yes, that is my plan: to use the Raspberry Pi in place of my laptop, using the laptop only for slicing and generating g-code (which would then be loaded onto a micro SD card to be run on the printer). I simply wanted a full graphic interface.

If you run Printrun/Pronterface 'locally' on your printer, you will still need to get the sliced G-code over to the machine and trigger the print job. If you are happy with this workflow (as I was for many months before I setup my OctoPi) then as Neil says, Panelolu will do the job in a very neat, standalone way; simply copy your gcode onto an SD card, slot it into the Panelolu and select the job from the Panelolu menu.
The Panelolu will give you useful information during the print such as bed/extruder temperature, and some vague idea of how long the job will take (based on the amount of gcode streamed off the SD card as a proportion of the whole file I think, so it's not 100% accurate) as well as simple controls to help with setting up jobs and simple maintenance.

OctoPrint isn't a network relay - it is a print server. It provides all the functionality that you'd expect to be built in to a regular network printer - once you've sent the job to it, you can log off/turn off your computer and Octoprint will continue controlling the printer until the job finishes. It also does all of the Panelolu stuff and more but over a web interface, so you can monitor and control the printer from any device with a web browser (including your phone). If you don't have a network connection then there's no point in it but a £10 cheap wifi dongle in one of the USB ports would fix that.

Essentially, if you don't mind shuttling a storage device between your 'slicing' computer and your printer then get a Panelolu. If you want to just send jobs to your printer like you would with any network printer then get OctoPrint.

I can't think of a usage scenario where running Pronterface on the Pi will make things easier than a Panelolu. In an ideal world we would be able to send STL files directly to the printer and have it automatically slice them with our specific printer parameters before starting the job but I don't think the Pi is powerful enough to do that within a timeframe that would be worth the hassle.

I just like the full graphic interface that Pronterface has, but I don't want to be dependent on a network - or my laptop - to use it. For that matter, Nophead says the Raspberry Pi could probably slice, though it might be a bit slow.

We're following each other around this morning...

That's fair enough. I find that I don't use most of the features of either OctoPrint or my Panelolu during 99% of all my printing activity, but the seamless transition from model to slice to starting a job is what I find valuable (because I would otherwise have to keep coming back to the room where my printer is located).

I'm sure the Pi *can* slice - my point is simply that it's probably too slow to be worth the time and effort, though I would love to hear from someone who has actually done it so that they can support or refute this assumption. Please do share your experiences with us if you succeed in doing this!

Well, right now I am struggling to get a Marlin version flashed, per another thread, that supports the P2 while keeping NopHead's changes.

Got to get ready for work now...

Okay, got my P2 "talking" to my Melzi, finally.

Now, on to the next thing. I want to install Printrun/Pronterface on my Raspberry Pi. I do NOT have a way to hook the Pi up to the ethernet, nor do I have a way to connect it to WiFi. Also, I do not have a keyboard - my only interface, at present, is a 3.2" touchscreen. The "sudo" commands given on Github for installing Printrun in Debian/Linux is therefore not going to work. Is there another way? In other words, is there a Linux version I can load onto a USB flash drive from my Windows computer, and then install from the flash drive after plugging it into one of the Pi's USB ports?

Unless the touch screen can emulate a keyboard like phones and tablets do then I don't think you can install software with no keyboard or network connection. As far as I know you need one or the other and a network connection is by far the most useful as you can telnet in to get command line access and then install VNC to get a remote desktop.

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[www.hydraraptor.blogspot.com]

Yeah, so much for my $30 computer. I just ordered a Logitech K400 wireless keyboard (which is supposed to work quite well with the Raspberry Pi, from the reviews I have read), and a 7" monitor that plugs into the component video port and will let me see what I'm doing a bit better. I was hoping for a 100% self-contained system I could run off the 600 watt PSU on the printer, but it looks like the best I am going to get is a system that is not dependent on my laptop (except for slicing, but I will try that on the Pi just to see how well it works).

Once you have set it up I don't see a reason for a keyboard or a screen.

I just put the RPI on my home network and so never need a keyboard or a screen and control my machines from anywhere in the world with a mobile phone, although in practice I nearly always use a PC somewhere in my house.

To set it up without a keyboard or screen you only need an ethernet cable to your laptop (assuming it has an ethernet port, you don't need a hub to network two computers) or a USB wifi dongle if you have wifi.

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[www.hydraraptor.blogspot.com]