KlackEnder for Elegoo Neptune 4

Why KlackEnder for the Neptune 4?

I got really annoyed by the temperature-shifts by the original inductive probe. When I heated my bed to 110°C for ASA and the printer homed, the z-offset got messed up, so I wanted something else: a BLTouch, a better inductive probe and I did some research and found @ErickSaint's “Elegoo Neptune 3 Pro/Plus/Max KlackEnder Remix” and as the Neptune 3 and 4 aren't too different from each other, I wanted to make it work with the N4 as the costs for the KlackEnder were 0.4€ for me (price per switch, had to by 5 at least) and nothing else was needed (Except from some screws and some magnets).

Parts required

• Screws:
  • M3x12-16mm (1pcs)
  • M2x10mm self tapping (recommended but not required) (2pcs)
  • M4x10mm (2pcs)
• Soldering Iron
• Some 22awg wire (~30cm = not much)
• Any Omron D2F (I got it here from voelkner.de for 0.45€ per switch)
• 6x3mm magnets (I got these from AliExpress affiliate) (6pcs)

Building

Printing

I'd recommend printing all the parts from ASA/ABS/PETG for better heat resistance.

You'll need get the following files from EricSaint's project: 

• probe_block_left.stl
• probe_mount_toolhead.stl
• probe_retainer_left.stl

The file “probe_dock_left.stl” IS NOT NEEDED. You'll want to download it from this page/project by me, as the N3 and N4 are slightly different. Print all of them with 0.2mm layer height. One recommended 40% infill, but I printed it with 20% or so, as it doesn't really matter that much.

I'd also recommend printing the “Nuts for 2020 Aluminium Extrusion” by @werz99, specifically the 2020-Hammer Nut M4.stl file. M3 worked fine as well, but the screw heads are barely big enough to hold the retainer, so I'd recommend going with M4 screws on the retainer.

Assembling

Just follow the instructions by @KevinAkaSam for:

1. The probe block
2. The probe mount
3. And the retainer.

I'd recommend widening the hole for the magnet with a screwdriver at the top a tiny bit so you can push it in and afterwards push it further with the use of a thinner screwdriver.

Mounting

At first, remove the extruder toolhead. Remove the belt “anchors” under the printhead, remove the cable and remove/loosen the top wheels enough so you can take the printhead off. Now, remove the 3 screws from the back and the 2 from the front holding the plastic cover on. 

Now, unplug the original inductive probe and don't loose the screw, we'll need it again! Screw the Probe Block into the same hole with the same screw as the original sensor. Now, you'll have to solder. The pictures below show you where to solder the cables and how as well. One end has to go to ground (the one attached to the side of the socket) and the other one onto the “signal” pin, which is on the top, as it was way easier to solder a cable there, than to solder it onto the correct pad at the switch, as there's no real room to work with and by that, you can pretty easily revert to the original sensor as well. But make sure that the cable at the top doesn't stick out too far, as there will be the plate attached above. Also remember to plug all the cables back in! Now, you can reassemble everything.

Lastly, you'll want to mount the Probe Retainer using the M4 screws and the printed hammer-nuts and mount the Probe Dock as seen in the cover picture using the original screw.

Configuration

As I'm running OpenNept4une, it makes everything a bit easier. You'll want to get these macros from Github and uncomment all the “imports” in klack-probe.cfg except the [include ./klack-adaptive-bed-mesh-calibrate.cfg]. This should stay commented out. This is the relevant section of my klack-variables.cfg:

[gcode_macro _User_Variables]
variable_safe_z:             30    # Minimum Z for attach/dock and homing functions

variable_bed_size_y:            225    # Y bed size used for centering the toolhead
variable_bed_size_x:            225    # X bed size used for centering the toolhead

variable_docklocation_x:        0    # Dock X location where moving the toolhead during attach and dock

#Attach move
Variable_attachmove_x:          0    # Final movement done to remove the probe from the dock

#Dock move
Variable_dockmove_x:            165  # Final movement done to remove the probe from the toolhead
Variable_dockmove_z:            6    # Retainer location on Z, this is the ABSOLUTE Z height where toolhead will be moved to release the probe 

variable_verbose:             True   # Enable verbose output
variable_debug:               True   # Enable Debug output

Note that these values only apply to me, as the Probe Retainer may be mounted lower or higher, depending on your setup. In your “normal” printer.cfg, you'll want to modify the following sections:

[stepper_z]
...
position_min: -15 #!MOD
...

Remove the PROBE_CALIBRATE macro and the [homing_override] section. That should be it. That's at least what was required for my OpenNept4une setup and I don't really know what else would have to be changed on the original firmware.

Happy Klacking!

Modified probe_dock_left.stl by @ErickSaint. All other parts are only mirrored by Erick as well.