Elegoo Neptune 3 Pro Klipper Upgrade with BTT Pi 2

Introduction

This is remix of https://www.printables.com/model/841472-elegoo-neptune-3-pro-klipper-upgrade-with-btt-pi-v

Thank's to the original author who provided helpful and detailed instructions.

BTT Pi 2 has a different hole spacing compared to BTT Pi 1.2

Thank's to the original author who provided also .step file, I managed to modify the original design to match the BTT Pi 2 hole spacing (even without my lack of 3D knowledge, and lack of available/working Autodesk Fusion 360 for Gnu/Linux)

This design for BTT 2, has only the hole spacing different, compared to the original design for the BTT 1.2.

Doc for BTT Pi 2: https://global.bttwiki.com/Pi2.html

One benefit of Pi 2 , is that it has an embeded 32GB eMMC so you install the OS on it instead of an unreliable MicroSD card.

Installing Klipper on BTT Pi 2

• I'm not covering this part

• See https://global.bttwiki.com/Pi2.html

Instructions

• Follow the original directions for Pi 1.2 from https://www.printables.com/model/841472-elegoo-neptune-3-pro-klipper-upgrade-with-btt-pi-v

• Below are either additional informations, or differences from Pi 1.2 and Pi 2 or difference of my setup configuration.

Flashing the printer

Use directions on the original article I remixed from.

Addition informations for Pi 2

Hole Spacing 

• BTT Pi 1.2 holes spacing

• BTT Pi 2 holes spacing

  • 49.4mm spacing on one direction is the same

  • But not for the other direction

• Btw we can notice the GPIOs pins are not on the same side of the board

My setup using 2 different serial connections

On my  BTT Pi 2  setup, I wanted to use 2 serial connections:

• On Pins 8/10  (UART2) /  /dev/ttyS2  , I want to keep a serial connection available, so I can plug itto my computer to access the BTT Pi2 in case of Wifi problem etc... This use a PL2303 USB interface . I can connect from my laptop for example using sudo screen /dev/ttyUSB0 115200   (this require to have set 115500 speed (see below)  . You must keep console=ttyS2  to have the console available on that tty.

• On Pins 21/23 (UART5) / /dev/ttyS5 ,I'm connecting serial connection to the 3D Printer.

UART 2 for Console (Serial access from computer)

I wanted to keep a "Console" terminal available on the "default" serial (UART2). That way I can connect from my laptop in case of Wifi problem or debug something.

• GPIOs for UART2

On the Board itself:

• On Pi2  I set ttyS2to 115200 bauds because the 1500000 (1.5M) is too much (at least for my PL2303 adaptor). See part console=ttyS2,115200below.

I modified as follow /boot/boot.cmd

biqu@bigtreetech-cb2:/boot$ vi boot.cmd 
#if test "${console}" = "display" || test "${console}" = "both"; then setenv consoleargs "console=ttyS2,1500000 console=tty1"; fi
if test "${console}" = "display" || test "${console}" = "both"; then setenv consoleargs "console=ttyS2,115200 console=tty1"; fi

• I kept this part into /boot/armbianEnv.txt

console=display

• Wiring of the PL2303 is usualy:

$ lsusb
Bus 001 Device 065: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port / Mobile Phone Data Cable

• Access to the Pi using the PL2303 (plugged on my laptop /dev/ttyUSB0) cable now available:

$ sudo screen /dev/ttyUSB0 115200

 '�ꋤ>g���eOG_/o/�
                                                                                     �WGnf���wOGN&��+&gt;���Ջyj�����[����5VSJoҝ�G����J�F/�����U�n<���$v����[������G�����
                                                                      ����UoF�ɷ���O�F/����F/�+G[0�����F/���_w���y����Q�ᨇCeW���F/���KF/��<�n��o�
Armbian 25.11.2 bookworm ttyS2 
bigtreetech-cb2 login: 
bigtreetech-cb2 login: 
bigtreetech-cb2 login: 

Goal is to able to connect to debug in case of WIFI issue for example.

UART 5 Serial connection to the printer

• UART 5 GPIOs

• We must enable UART5 using overlays parameter:

/boot/armbianEnv.txt 

overlays=uart5_m1

(yes we must add _m1 not sure why) 

• Once overlays is added , after reboot, we see the additionnal /dev/ttyS5 device now availabe

biqu@bigtreetech-cb2:$ ll /dev/ttyS*
crw-rw---- 1 root dialout 4, 66 Dec 15 23:38 /dev/ttyS2
crw-rw---- 1 root dialout 4, 69 Dec 15 23:38 /dev/ttyS5
biqu@bigtreetech-cb2:$ 

• Once it is confirmed available, /dev/ttyS5 can be defined into the printer.cfgas the way to connect t the printer over serial.

• printer.cfg 

Use https://github.com/TheFeralEngineer/Klipper-for-Elegoo-Neptune-series-3D-Printers/blob/main/Neptune%203%20Pro%20config/printer.cfg but define the /dev/ttyS5

• On Robin Nano side, the the Serial connections are:

• And TX and RX on the Pi2 (for UART5) are pins 21 and 23:

• As usual connect TX (RobinNano) <-> RX (BTT Pi2)   and  RX (RobinNano) <-> TX (BTT Pi2)

Pick the GND you like

Powering the Pi2

• 12V/24 V on the Robin Nano 2.2 Board

• Power Input on the BTT

🚨 GND and 12/24V is NOT on the same side on BTT Pi 1.2 , and on BTT Pi 2  🚨

GND and 24V are indicated on the reverse side on the BTT Pi 2 board, so you can't be wrong by checking yourself.

Other informations

• DuPont Jumper Wires

Because the GPIOs are not on the same side of the board, for Pi 2, 20cm lenght could be good but I used 30cm too as it better avoid the fan location.

• Printing

  • PETG as it may be hot inside

  • 20% infill with "triangle"

• Nylon washers

  • For the 4x M2 Screws, to be on the safe side, I used some Nylon washers I already had.

  • Search on Aliexpress for Nylon Plastic Insulation Washers M2 M2.5 M3 M4 M5 M6 M8 Spacers Seals Washer Fastener Box Packed Gasket Ring Kit

Also btw, I used a solder iron few seconds on the top of the screw, so it's easier to screw it into the PETG.

• I had an old TF Card extender available (you can see on pictures) , so I pluged into to slot of the Pi2  (without microSD card by default because I use the on board 32GB eMMC for OS) ... But in case of problem, I may be able to reboot the board on the MicroSD card, without opening the 3D printer.

• The BTT Pi2 Wifi antenna is also outside of the metal frame

Cable management result

With  USB extender and USB WebCam :