Ender-3 V3 SE - my way to klipper

Preface

The day before Christmas

It was a week before Christmas 2023 when I received the note that I won an Ender-V3 SE. After some years of experience with the first version of the Ender-3 I was looking forward to have a 3D printer which comes with all the extras I mounted on my initial Ender-3 from summer 2020. Bed level sensor, silent stepper drivers, yes, even a Z-offset sensor. 

So I was really excited when I held the shipping package in my hands the day before Christmas.

After screwing everything together and doing the bed leveling I was able to print a Benchy only 20 minutes after I started to unpack the printer. What an experience. No piece of paper, no wild turning on the bed screws. It just worked out of the box.

But as soon as I started to print functional things, I also started to miss some things Marlin, the GPL licensed firmware for the printer, offers. So why not simple compile an own version of the firmware with the missing options (mainly pressure advance)  and install it on the printer? I mean I did that with the original Ender-3 again and again (initial version was the 1.x, Marlin just released the 2.x version at that time).

But unfortunately Creality has chosen to violate the GPL license and don't release their modifications to Marlin or the configurations used to compile it. 

(I have an email in which Creality states that the machine "doesn't support open source", it seems somebody in China really struggles to understand the GPL and the fact that the end user has the right to obtain a copy of the source code used to compile the firmware).

So compiling Marlin was not an option. But what could I do to have PA enabled on my printer?

And at that point I stumbled over a Discord discussion about Klipper on the Ender-3 V3 SE.

So I decided that I will use Klipper.

Get ready to rumble

OK, decision made, but where to start?

I know Klipper requires a computer to run of. Since I use Octoprint for years, that requirement is easily met by my Raspberry PI 3B+ which is already connected to the printer.

It took not long until I noticed that the user 0xD34D (0xD34D Github account) forked the Klipper firmware repository and made the changes required to get the V3 SE running. Including the bed leveling sensor (called PRTouch) as well as the Z-offset sensor (which is a load cell connected to an HX711 ADC).

And that's said repository:

Klipper version for the Ender-3 V3 SE

OK. That's the first step, but what now?

The way to Klipper

The github user dw-0 Github created a set of scripts to get Klipper installed, called kiauh. I used that lovely piece of software install Klipper on my Raspi.

So first I followed the steps on https://github.com/dw-0/kiauh to get kiauh installed.

Afterwards I installed everything using the following process.

Now it's time to configure the software (Klipper and moonraker) which is running on the computer attached to the printer.

Please be aware that many of the tutorials out there are outdated and don't reflect the current directory configurations.

I write here what worked for me.

That's all?

At this point Klipper is installed on the V3 SE and on the control computer. Is it perfect? No it isn't. But it's already way better than the "closed source" (AKA GPL violation) original firmware.

But there's still something missing:

• The printer display

The  display attached to the SE is not working with Klipper at the moment. Some people are currently (end of January 2024) in the process to reverse engineer the function of the display.

• PRTouch V2

According to some half-hearted release of the source for the KE (sourc code of some parts still missing) Creality has developed a "different" approach for their PRTouch called bed level sensor.

Klipper is using the "old method" which is working quite fine. So no missing functionality but I think this small facts shouldn't be kept hidden.

What's next? 

What? That's not all?

No, not really. So here are some remarks:

New commands added by 0xD34D

The following commands were added and can be called via the terminal (mainsail, fluidd or octoprint)

PRTOUCH_PROBE_ZOFFSET

This command determines the Z-Offset of the nozzle 

PRTOUCH_ACCURACY SAMPLES=10 PROBE_SPEED=1

This command tests the Z-offset probe for 10 times and returns the statistics of the accuracy of the sensor

Input shaping sensor

If one follows the procedure described on the Klipper page to make the input shaping sensor working, most likely it will fail. 

To fix that, simply install the package "libopenblas-base" on your raspberry and try it again (sudo apt install libopenblas-base)

A recently (mid February 2024) accepted pull request on Klipper added all the required information to the official Klipper documentation. So one just have to follow the docs.

https://github.com/Klipper3d/klipper/blob/master/docs/Measuring_Resonances.md

My "best" practise

As many hobby related things the workflow one choses is like a religion. There's a lot of grey area between wrong and right, and I just recently started using Klipper.

Z-Offset: The Z-offset (the difference in height between the nozzle and the PRTouch probe shouldn't change until one replaces the nozzle. That's why I decided to determine it once (and finetune it) and not do it on every print

Mesh: Here I decided to measure the mesh before every print. It only takes minute. Additionally I decided to use the addon "KAMP" which scales the mesh point down to the actual printing area

My Klipper configuration mess

A small backup script I wrote saves the changes of my configs to my (public) github repository: Schnoogs' Klipper Config Abyss

Troubleshooting - my experience (yet)

An user on reddit used the method above to install klipper. However, the connection with the serial interface failed.

The user contacted me for help.

What I found out:

His newly installed Raspbian failed to enumerate the /dev/serial/by-id  paths, so that the setting

serial: /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0

in the printer config failed to define the connection. 

Quick solution

• disconnect the printers USB cable, wait 5 seconds. 
• plug the USB cable in, wait another 5 seconds.
• execute the following command in your ssh terminal

find /dev/serial/by-path/ -lname '*'$(dmesg | grep USB | tail -n 1 | rev | cut -d " " -f 1 | rev)

• the output is the path to the printers serial port, in my case "/dev/serial/by-path/platform-3f980000.usb-usb-0:1.3:1.0-port0"
• change the printer.cfg to
• [mcu]
  serial: <the output the command gave>

How we solved it (the more complicated way):

• disconnect the USB cable and wait for 5 seconds
• plug the cable in again and wait another 5 seconds
• Running the command "dmesg" from ssh 

 That should output something like 

[2395031.301884] ch341 1-1.3:1.0: ch341-uart converter detected
[2395031.305616] usb 1-1.3: ch341-uart converter now attached to ttyUSB1

That shows that the printers serial is attached to ttyUSB1 (in the users case ttyUSB0)

OK, so let's remember ttyUSB1

• Running the command "ls -la /dev/serial/by-path/ | grep USB1"   (in the users case USB0) which gives the following output

 lrwxrwxrwx 1 root root 13 Apr 20 10:22 platform-3f980000.usb-usb-0:1.3:1.0-port0 -> ../../ttyUSB1

platform-3f980000.usb-usb-0:1.3:1.0-port0 in my case is the path-id of my printer (that depends on the USB port used on the pi, so this is individual to each setup)

• Glue the path together:     /dev/serial/by-path/platform-3f980000.usb-usb-0:1.3:1.0-port0    

OK, now we have the full path for the serial console and just need to adjust our printer.cfg

by changing 

[mcu]
serial: /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0

to

[mcu]
serial: /dev/serial/by-path/platform-3f980000.usb-usb-0:1.3:1.0-port0

and it works. 

However, this solution(s) come(s) with a caveat: You always need to use the same USB port on the raspberry pi.