Ender3V2-Inductive-Probe-Tutorial

This repository includes includes information on how to install a generic inductive probe on an Ender 3 V2, using mriscoc's Professional Firmware.

Important

Inductive probes only work on metallic print beds, it will not work on a glass or garolite print bed, I recommend using a PEI coated spring steel print bed.

Note

The Ender 3 doesn't have a very stable structure, even with dual Z-rods, and often comes misaligned out of the factory. Your mileage with any form of bed leveling will vary due to this.

I don't have a dual Z upgrade and I tried my best to level the upper frame and the gantry, despite my efforts I still can't get a perfectly accurate bed mesh especially towards the right where the gantry is unsupported.

Caution

This tutorial is based on my own setup and yours might differ, try this at your own risk, I'm not responsible for any damage to your printer.

Probe information

I bought a generic looking inductive probe from a local 3d printer store, with the model name "LJ12A3-4-Z/BX", it has a 12mm diameter and has 3 wires coming out of it.

The label on the probe explains the pinout like this:

Brown = Voltage IN
Black = Signal
Blue = Voltage OUT/Ground

The Signal pin is pulled high when the probe detects metal.

Its designed to run between 6-36V but in my experience it worked fine with 5V from the BL-Touch port on the mainboard.

But your probe might be different, so make sure to check its label/documentation for the correct pinout and voltage.

Wiring

Most probes come with bare wires, so you will need to solder headers, a 5-pin JST connector is the proper option but if you don't have the equipment, DuPont headers will also work, there is also a 3D printable model you can use to convert seperate DuPont headers into a JST connector. I also recommend hot-gluing the connector to the mainboard to prevent it from falling off with vibrations.

You need to connect the 3 wires to the "BL_T" port on the 4.2.2/4.2.7 mainboard, using this pinout:

Brown(VIN)    = V(+5V)
Blue(GND)     = G(GND)
Black(Signal) = OUT(Signal in)

You can consult the diagram below:

Mounting

I used this 3D model by Firedrops to mount the probe to my tool head, you will need 2 M3 x 5mm screws or longer.

Align the probe vertically so that the red light comes on when the nozzle is very slightly above the print bed, and then tighten the nuts, I had to remove the washer on the top as it was interfering with the mounting screw.

Firmware

You will have to compile the firmware yourself, I'm only going to show the required configuration changes, as the compilation process is explained better elsewhere.

Clone the Special Configurations repository and use the Configurator to generate an EZABLI config with UBL enabled and the options specific to your mainboard/printer setup, then modify the Configuration.h like this:

#define Z_MIN_PROBE_ENDSTOP_HIT_STATE LOW // I'm not sure why, but I had to set this to low despite my probe pulling the pin high. If your tool head tries to move up while homing or fails to home, invert this.

// #define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN // Comment this, as our probe is connected to the BL-Touch port

#define NOZZLE_TO_PROBE_OFFSET { -43, -1, 0 } // Change this if you are using a different mount than the one linked above

I included the prebuilt Manual Mesh, EZABLI, and my own inductive probe configuration in the configurations directory in this repo, so you can compare how they differ.

Final setup

Set up your Z offset using any method you prefer.

Refer to the Marlin firmware UBL documentation to find the G-code commands to add to your slicer settings.

Credits

Mainboard image cropped from this post in r/EnderCommonSense by u/Diablo996