• BTT Eddy Dimensions and Probe Location
• Compiling Firmware
• Printer Configuration
• • Z Endstop
• Drive Current Calibration
• Mapping Eddy Readings To Nozzle Heights
• Bed Mesh Calibration
• Temperature Compensation Calibration
• Bed Mesh Calibration Parameters
• Bed Mesh Scan Height
• Bed Mesh Rapid Scanning
• FAQ - Frequently Asked Questions
• • Sometimes I get a "Probe Triggered Before Movement" Error
• • Eddy is performing Z Hops when running Bed Mesh
• • Which Eddy version should I use?
• • My z-offset doesnt seem to save and resets, is there a work around or fix?
• Known Issues

For a video tutorial covering many of the points below, please watch the video located here

The dimensions below will help you to understand where the center of the coil is when measuring the X and Y offsets from point 15.

1. Change to BTT klipper by entering the following via SSH

cd ~/klipper
git remote add eddy https://github.com/bigtreetech/klipper
git fetch eddy
git checkout eddy/eddy

2. SSH into BIGTREETECH PI or your host device
3. Type

cd ~/klipper
make menuconfig

4. Use these settings to compile the firmware.
5. Once set, hit 'Q' and when asked, select yes to save.
6. Type make to compile.
7. Disconnect power to Eddy
8. Push and hold boot button on Eddy (Its next to where the cable plugs in) and at the same time, plug in the cable to your BIGTREETECH Pi
9. SSH into host device
10. Type lsusb into the command line. You should see eddy.

11. Type cd ~/klipper into command line

12. Type make flash FLASH_DEVICE=2e8a:0003 Remember to change 2e8a:0003 to your device ID you found in step 9

13. Type ls /dev/serial/by-id/* into the command line. The found device will be what you enter into your klipper config under [mcu eddy] for the Serial variable.

    [!NOTE]

14. Type into command line sudo reboot

16. Place Eddy Approx. 20mm above the bed. If you plan to use the Eddy as an endstop then you will not yet be able to home with it and you will need to manually move the gantry or bed such that the Eddy is 20mm above the bed.
17. From Mainsail or Fluidd run the command LDC_CALIBRATE_DRIVE_CURRENT CHIP=btt_eddy
18. Type SAVE_CONFIG to save the drive current to your config

Now that the drive current has been calibrated, the Eddy will be able to obtain readings from the print bed. Klipper needs to know how those readings correspond to the height of the nozzle. The following calibration procedure positions the nozzle on the bed so that the z height is = 0. It then takes readings from the Eddy as it gradually increases the nozzle height so that it can map those readings to known heights. Follow the steps below to perform this essential calibration.

19. Send the command PROBE_EDDY_CURRENT_CALIBRATE_AUTO CHIP=btt_eddy
20. Follow the prompts on the klipper UI to lower the nozzle until it sandwiches a piece of paper between it and the bed but be careful not to dig into the bed. The paper should still be able to move with some force applied.
21. Click accept and watch as the Eddy performs the mapping. Be sure to send SAVE_CONFIG when it is done. Skip ahead to Bed Mesh Calibration.

22. Home X and Y axes with command G28 X Y

23. Make sure you dont have a bed heightmap loaded. Send BED_MESH_CLEAR from the console to clear the heightmap.

24. Move Nozzle to Centre of the bed with G0 X125 Y125 F6000 . The given command assumes a 250x250 printer but you will need to adjust it for your bed size. Take your bed size and divide it by 2 on X and Y and then use those values for the X and Y values in the command.

25. Start the mapping by typing PROBE_EDDY_CURRENT_CALIBRATE CHIP=btt_eddy. You will see an adjustment box that will allow you to lower the nozzle. Lower the nozzle until it sandwiches a piece of paper between it and the bed but be careful not to dig into the bed. The paper should still be able to move with some force applied.

26. Once completed use SAVE_CONFIG

27. Home All Axes
28. Use command BED_MESH_CALIBRATE METHOD=scan SCAN_MODE=rapid
29. Once completed use SAVE_CONFIG

30. Home All Axes and move Z 5 mm above the bed by typing G0 Z5 or using the movement UI.
31. Set idle timeout by typing SET_IDLE_TIMEOUT TIMEOUT=36000
32. Run PROBE_DRIFT_CALIBRATE PROBE=btt_eddy TARGET=56 STEP=4
33. This will cause the UI to display the z axis adjustment box. Use the paper method mentioned here to pinch a sheet of paper between the nozzle and the bed and then accept the value.
34. Turn on your heat bed to the maximum value and your nozzle to 220C.
35. If you are in a room with an air-conditioner or an open window, it would be good to turn it off and/or close the window. We want the temperature of the Eddy to rise and breezes will stop that.
36. As the Eddy temp rises you will automatically be asked to perform the paper pinch method at each 4C interval. Be careful not to burn yourself on the bed as the bed can get quite hot.
37. Repeat the paper test method until the calibration completes. If you find that the temperature of the Eddy is no longer increasing then you can end the calibration early using the relevant command below.

    [!NOTE] By default the calibration procedure will request a manual probe every 4C between samples until the TARGET is reached.

    The following additional gcode commands are available during drift calibration.

    PROBE_DRIFT_NEXT may be used to force a new sample before the step delta has been reached.

    PROBE_DRIFT_COMPLETE may be used to complete calibration before the TARGET has been reached.

    ABORT may be used to end calibration and discard results.

38. Youre all done and your Eddy will now give you a beautiful first layer across a wide temperature range! :)

The Eddy allows you to perform a very rapid bed mesh scan before each print to ensure that you get the best first layer possible. To do this, we recommend replacing the standard BED_MESH_CALIBRATE macro with our modified version from the sample configuration file and then including a BED_MESH_CALIBRATE call in your print start macro.

To find out more about the parameters used in the bed mesh scan you can read the Klipper documentation here: Bed Mesh Calibration

The scan height is set by the horizontal_move_z option in [bed_mesh]. In addition it can be supplied with the BED_MESH_CALIBRATE gcode command via the HORIZONTAL_MOVE_Z parameter.

The scan height must be sufficiently low to avoid scanning errors. Typically a height of 2mm (ie: HORIZONTAL_MOVE_Z=2) should work well, presuming that the probe is mounted correctly.

It should be noted that if the probe is more than 4mm above the surface then the results will be invalid. Thus, scanning is not possible on beds with severe surface deviation or beds with extreme tilt that hasn't been corrected.

When performing a rapid bed mesh scan there is little time to accumulate many samples per point so that they can be averaged and have noise removed. Therefore a rapid scan may not be as accurate as a standard bed mesh scan but in most cases it will still produce a fine first layer.

Rapid scans can be improved by allowing the travel planner to slightly overshoot the scanned bed mesh and smooth the moves. You can configure this overshoot in the bed_mesh configuration section using the scan_overshoot: parameter. Note that you will need to ensure that the axis can travel to the mesh boundary plus this overshoot value on your printer so be careful not to specify a value that is too high. Usually 8mm is plenty.

• This will happen when you try to execute two successive PROBE commands. Always raise the gantry by a few mm between PROBE commands to avoid this.

• Make sure you are using the correct macro call. BED_MESH_CALIBRATE SCAN_MODE=rapid METHOD=scan
• Remove or alter KAMP - Adaptive Bed Mesh and any custom BED_MESH_CALIBRATE macros. Use klipper adaptive mesh instead or alternatively do not include KAMP/Adaptive_Meshing.cfg in your KAMP_Settings.cfg Information on Adaptive Mesh Here

• It depends on your needs. Eddy USB and Eddy Coil are nearly identical, however Eddy Coil is more for toolhead boards and connects via I2C connectors.
• Eddy Coil does not have temperature compensation and so it may be less reliable for homing if you are using it within a sealed chamber..

• Coming from a standard probe, this may seem like a bug. However if you have calibrated the Eddy correctly and are using the special homing macros, then there will be no need for a z-offset. Explaining why is a bit long winded but essentially when it comes to an Eddy, the z-offset parameter does not adjust the height at which the nozzle prints, it just adjusts the height at which homing or probing triggers. If you have a mind that enjoys understanding things at a deeper level then here is a writeup to give you something to chew on: Z-Offsets with Eddy Current Probes
• While we strongly recommend simply performing the Eddy probe calibration in order to get a nozzle height that is just right, you can still simulate a standard z-offset by uncommenting certain macros in the sample configuration file. Simply uncomment any macro that is related to the beta z-offset functionality and you will be able to use the standard mainsail buttons to raise/lower then nozzle and save that height as a z-offset.

• BTT Knomi will cause z-hops during a scan. If you are using the Eddy as an endstop then simply comment out the G28 macro in KNOMI.CFG and use the macro from the sample Eddy config. If you are using another device as an endstop then modify your G28 macro in the KNOMI.cfg, specifically this line.

  SET_GCODE_VARIABLE MACRO=_KNOMI_STATUS VARIABLE=probing VALUE=True
  BTT_BED_MESH_CALIBRATE
  SET_GCODE_VARIABLE MACRO=_KNOMI_STATUS VARIABLE=probing VALUE=False
  

  so that it looks like this

  SET_GCODE_VARIABLE MACRO=_KNOMI_STATUS VARIABLE=probing VALUE=True
  BTT_BED_MESH_CALIBRATE SCAN_MODE=rapid METHOD=scan
  SET_GCODE_VARIABLE MACRO=_KNOMI_STATUS VARIABLE=probing VALUE=False