Continuing with my mission this week to actually finish the electrics on my DIY Prusa i3 MK2 3D Printer, in this video I make some modifications to the RAMPS board and the Arduino.
On the RAMPS I need to remove the 4 pin power connector. Now that the RAMPS board is not carrying the current to the heated bed it isn’t really a safety issue (although it might be if yours is carrying heated bed power…) but it just simply takes up too much space for how I want to mount it. And a soldered connection is more reliable that a connector, well usually!
I am also junking the polyfuses. Again not so much a safety issue now as there is only a little current going through them, but even so the 5 Amp one still feeds everything apart from the heated bed so they have to go. Replacing them with a simple blade fuse holder and fuses – you know, like off of cars n stuff 🙂
In the last video I created a separate MOSFET board to handle power to the heated bed. The gate of the MOSFET is driven high by pin D8 of the Arduino, so I also add a signal wire from D8 that can then attach to my off-board MOSFET.
Lastly, I remove the DC jack on the Arduino. It isn’t being used or causing any issues, but I just don’t like it… well no, it got in the way of my board mounts.
That just leaves fixing the corrupted garbage that appears on the LCD after a couple of minutes. After quite a lot of time spent (more than quite a lot..), I have fixed it. That will be the subject of my next video.
I have changed my mind a few times about how I plan to finish off my Prusa i3 MK2 clone 3D printer… but now I have settled on a plan! None of it was particularly complicated, but I just want to arrange things in such a way that they are safe, tidy and give me the best result.
As I plan to add a physical brace to the Z Axis frame, I want to combine that with a suitable housing for all the electronics. With the actual brace made I can start finishing off the electronics!!!
There are few items I want to do:-
Fix the issues with LCD corruption – presumably cause by electrical noise
Remove the Polyfuses and provide alternative
Integrate the Raspberry Pi in with the other electronics so it is a permanent feature on the printer, including power
Add in additional temp sensors to the electronics and power supplies that will kill the power if anything looks dodgy
Power the Heated Bed with 24V instead of 12V – but keep this 24V separate from the RAMPS board
The last of these is the item I am doing first – and it the subject of this video.
Below is my rough schematic showing how I will wire the RAMPS, Arduino and also a small external board that will perform the heated bed power switching. Beneath that the calculations I made to conclude that the AUIRFB8409 Mosfet would work fine:
Rough Schematic of an external board to switch power to the 24V heated bed, showing relevant parts of the RAMPS and Arduino
Main considerations in choosing the AUIRFB8049 Mosfet, with calculations
Up till now I have been using an old laptop to connect to the 3D printer through Pronterface. While this works fine, it does mean having to shift gcode files around on my network and to have to power up the old donkey… which can take a while… each time I use the printer.
From day zero I knew I wanted to get OctoPrint running on a Raspberry Pi so that I could control the printer from any web browser, upload gcode, start prints and as a massive bonus be able to watch how the printer is getting on via remote viewing a webcam.
In this video I run through, step by step, how I did this and how you could too for very little cost. As I discuss in the video there are at least two ways of doing this on a Raspberry Pi (OctoPrint is also available for many other platforms), the hard way which is preparing the Pi yourself, building OctoPrint and installing all necessary dependencies. Then there is the easy way, flashing an image of OctoPi. In this video I cover the latter method, although I will likely do another video covering the fully manual way.
At this time I see no downside to using the OctoPi image – but we shall see!!!
In order to do this yourself, aside of a Raspberry Pi and cables, you will need some freely available software. Here are the links to download that:-
If you are interested in reading all the documentation for OctoPrint you can find that on the website here.
If for any reason you need to know more about HAProxy you can spend a chunk of your life reading about it here. (Not for the faint hearted. Long story short, among other things, it is a server proxy that runs on Linux that can manage network traffic to and from the machine.)
In this video I go through some of the prints I have made in the first week after building the DIY Prusa i3 MK2, and some of the interim conclusions I have drawn from them together with the settings this had led me to change.
Long story short; it is quite hard to diagnose a lot of issues as they could be caused by a number of different things manifesting with the same symptoms. It maybe even a combination. I had to single out settings and go wild with them to see what effect they had and then apply that to my baseline. However, apart from filament getting stuck on the spool (my fault) I haven’t had any failures and all the prints have been perfectly fit for the job I needed them for. So really we are only looking at aesthetics.
I also gave Simplify3D a try out…. at this time I don’t really need any of the capabilities it has over Slic3r and found it to exhibit some unwanted artifacts on the prints I tried it out on. It is a little disappointing that they offer no free trial as it isn’t particularly cheap and is very much a piece of software you will either get on with or you wont. You have to first spend your money to find out… You can apparently get a refund though if it doesn’t turn out well. For the time being I am sticking with Slic3r as I get better quality prints and really the only feature I would use right now from S3D is the manual supports.
I have decided to make Octoprint my next upgrade as for the time being the electronics are holding together just fine. So on with that!!!