Cap. Sensor, Inductive Sensor, and Missed mm due to Risers

Basic Information:

Printer Model: 1403/Behemoth/self-made/cop-out
MCU / Printerboard: AR100/Recore

klippy.log (41.6 KB)

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Describe your issue:

  1. The capacitive sensor works in my case for PROBE_CALIBRATE.
  2. The printer starts to print, after PROBE_CALIBRATE, into the glass bed.
  3. I tried w/ another sensor. I used an inductive sensor but the sensor does not pick up the glass bed.

I am trying to print some items for a customer of sorts. Anyway…

I have a 300 X * 152 Y * 152 Z.

I think the issue is that my 152mm on Z is compromised. It is compromised in a way that creates for lack of mm for the entire Z-Axis.

I am measuring and testing now. W/ PROBE_CALIBRATE commands and TESTZ, I seem to get close to the printing surface but w/out touching it. Right. So, when the print starts, it smashes into the bed.

I have changed, due to the offset_, the amount of mm in the Z_Axis in the printer.cfg, OctoPrint GUI, and accounted for the missed amounts of space b/c of some risers-heater_mat-bed.


P.S. This seems a bit complicated when first viewed but I think someone can give some insight as to what I may need to do.


I removed the inductive sensor and replaced it back to the older capacitive sensor. I think the PROBE_CALIBRATE command works just fine but then it crashes the build plate. Anyway, I am going to try to make a gap of sorts, e.g.

TESTZ Z=-3 # Instead of Z=-4 and Z=-1

This way, what the printer expects is to start higher when printing? This may work. I will try it again.

It seems to me you are not understanding how to use probe_calibrate
I suggest reading these in order pay attention to the Paper Test section
Use an automated tool to determine precise Z heights!

first to read

2nd to read

The TESTZ command is to lower the nozzle down to the paper to find the correct probe offset
using a larger amount in the beginning ie TESTZ Z=-3 then TESTZ Z= -1 then TESTZ Z=-0.1 as many times as required to get the nozzle down to the paper as described in the docs

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@Blackstump ,

Okay…so from what I gather in those documents, PROBE_ACCURACY needs to be a command too.

Somewhere along the way, I missed and forgot about PROBE_ACCURACY for the z_offset.


P.S. I will have time soon to review my lack of interpretation and miscues.

@Blackstump ,

The glass bed is raised about 20mm off the surface of the 152mm Z_Axis. So, I have about 130mm of Z_Axis left after the raise.

Anyway, the hotend is burying itself in the bed. Please see below for what errors and ideas I have currently.


P.S. PROBE and PROBE_CALIBRATE both work but only if I issue a G0 Z5 or above command for the Z_Axis.

no trigger on probe after full movement

This error is directly associated w/ PROBE. After G28, PROBE shows no trigger after full movement.


P.S. So…

1. Am I allowed to move the Z_Axis after G28 and before PROBE?
2. Does a G0 Z5 command ruin my chances w/ PROBE after issuing the G28 command.
a. So, it would be this basically...
- G28 
- G0 Z5
and etc...


In source, are there any ways I can command the sensor to not accept its current state?

This would mean…

  1. The sensor is off?
  2. The heater_mat and glass_bed for my build surface are creating an issue for the sensor?
  3. I am not blaming Klipper right now!

This is a self-made (sort of) experiment on building bots for 3D Printing. Anyway, I could print w/ the Inductive sensor on a solid metal bed. This is not an issue.

I wanted to have a heated_bed for numerous reasons. One and so on…

Anyway, I have a total of about 3mm off b/c of the glass bed that is not picked up due to the sensor…

Yes. This is my fault. The glass bed holds no value outside of stabilized heating and smooth surface ideas.


P.S. That is my cry to action and I am sticking by it for now. If a Capacitive Sensor is not used in this field w/ a glass bed, okay. I will accept it. Omron sensors state they can sense glass. I am not saying they can or cannot as of now b/c I am trying still.


I need to fool the printer into thinking that the right height for the Z_Axis is 3mm or 4mm higher than it is printing at currently. Odd? Yes but I need to figure this out?

Does anyone have any ideas?

An inductive probe does not “see” your glass bed and only detects the metal thereunder. An inductive is not suited for glass beds.

Hello @Sineos ,

I did not make myself clear. I am using a Capacitive Sensor instead of the inductive sensor I used to use.



Is there a way to fool the source of Klipper into thinking that a Capacitive Sensor that only reads the output of the heater_mat instead of the top of the glass bed to this day?

I am asking…

  1. B/c I am going to order some metal tape.
  2. B/c using the glass bed is seemingly impossible for sensors (non-touch)…
  3. I will try a BL Touch and see how far I get…


P.S. Thank you guys/gals for the support. I have this gnarly printer that is out of service and I was going to surprise the boss w/ some Megasized Nuts and Bolts! Anyway, thank you again for putting up w/ me and my way of trying to explain things.

BLtouch runs fine with a glass bed.

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Awesome…I just ordered one. These things are not cheap. Sheesh.


P.S. If I run into issues, which I will most likely, I will come running back!

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So and yeppers here. The Cap. Sensor is judging the space at which the heater_bed meets the glass.

Anyway, there is no fixing this idea in source since my sensor is dictating the start of HOME and its own interpreted sensing.

So, sorry to take up space here.


P.S. Thank you guys/gals for putting up w/ me once more. The build is coming along nicely so far outside of this oversight. Anyway, thanks again!

Okay to Everyone Here,

If anyone was following along, this is not a Klipper issue. My slicer settings seem to be off by microns.

Anyway, I am working again!


@Sineos , @EddyMI3D , and @Blackstump ,

So here…

There it is for now. The darn printer was at fault twice. Well once. I was at fault for the slicer options and offset in the config.

Anyway, a new coupler/coupling and no more jiggity-jaggity-motion.


Thanks for the feedback.
Actually this is in-line with my experience and especially with what we see in the daily support. My personal ranking is:

  1. Not having read / understood / followed the documentation
  2. Subtle configuration issues
  3. Mechanical / electrical issues


  1. Things Klipper could do better


  1. A BUG!

@Sineos ,

Mine was a cfg issue on the Slicer side along w/ mechanical failures. Who knew a good coupling could go a long way?