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Wiring an Inductive Probe Sensor


Wiring diagram for NPN Inductive probe running 6-36 Volts

Probe Wiring

No doubt you’ve seen posts using resistors with these probes, we found it makes your probe unreliable, we prefer the 5.1 volt Zener diode method as shown above.

**Important** play close attention to the colour codes, these probes use international colour designations.

The signal wire from the probe is black and goes to the green end stop connector via the Zener diode, this limits the output of the probe to 5.1 volts. Pay close attention to the orientation of the Zener – yes the band on the Zener points TO THE PROBE.

The blue wire from the probe is ground and goes to the black ground end stop wire.

You might be thinking why not pick up voltage from end stop pin 3? – because it’s only 5 volts and these probes need at least 6 volts and work best at 12 – 24 volts. Connect the brown wire from your probe to the +volt supply of your printer, usually from an auxiliary connector. You can pick up 12/24 volts directly from your power supply output if you prefer, but double check the voltage first.

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Control and Adjust Your 3D Printer with Pronterface

PronterfacePronterface is a super handy program that allows you to easlily control and adjust your 3D printer without messing around in firmware. Pronterface is a portable program so no install is required, just save it somewhere convenient, right click the exe and send a shortcut to your desktop. You can grab the latest windows disto here or you can find other distos on the main download page here – Pronterface is contained inside the Printrun disto.

One of the toughest things to get your head around when setting up your printer is the Z offset. Usually it’s a negative value to move your nozzle closer to your printbed after the printer has homed to zero. A correct Z offset is critical for successful prints, too far away and your print might come off and your first layer will be ugly, too close and you will get the “Elephants Foot” effect – a wavey first layer and possibly squshed layers higher up. I think most of us stuffed this setting up at some stage, so here’s an easy way to set it using this handy program.

To get started make sure your print bed is as level as possible by running the corner level proceedure (usually with a sheet of printer paper) – if you’re not sure how to do this check out the article here.

At this point you should make sure you have some clearance between your nozzle and print bed or you risk scratching your build plate.

Ok, make sure you have downloaded Pronterface, fired it up, connected your printer and connected the program. Now you’re going to run each one of these commands (in bold) individually by entering them in the send window and hittting send or enter on your keyboard.

G28 – this will home the 3D Printer

G29 – This will run an auto bed level for your 3D Printer if you have it.

G1 X50 Y30 F1000 – This command will position the nozzle somewhere close to the front of the bed

G1 Z0 – Move nozzle to Z absolute Zero

M114 – This will verify the current position of the Z-Axis is actually zero

M211 S0 Turn Off the Software Endstops (so you can move below zero)

At this point, you can use the Pronterface interface to manually move the Z-Axis/nozzle down by using the Z 0.1 button on Pronterface until a piece of paper just catches between the nozzle and the bed.

Once you have the setting correct so the paper is just able to barely move follow the commands below to finish.

M114 – This will verify the new position of the Z-Axis – write it down.

Set this new value with the M851 command. (ensure you set it to the number you wrote down) For example M851 Z-1.4 would set the z offet to minus 1.4, M851 Z1.4 would set it to plus 1.4

M851 Z-1.4 Sets the new Z offset (remember the Z-*.** needs to be the value you wrote down)

M503 – Will display all the settings in your printer, look for the Z Offset value – this verifies the new value was accepted

M500 Saves the new values to EEPROM, if you don’t run this command your new setting will be lost when you power off your printer.

This is just one setting you can change using pronterface, check out our list of G and M codes here with a brief description of their function.

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Easily convert STL files into solid STEP files.

STL to Solid FreeCAD

Converting is a cinch in FreeCAD.

Converting is a cinch in FreeCAD. Source: Benjamin Goldschmidt / All3DP

A free alternative with which you can convert STL files to STEP files is FreeCAD, a downloadable CAD program. First, you need to bring your STL file into FreeCAD.

  1. Hit File -> Open and select your STL file.
  2. Once open, ensure that you have Tree View open by going to View -> Panels -> Tree View.
  3. Ensure that “Part” is selected in the drop-down menu at the top middle of the screen.
  4. With the file name selected in Tree View (CSG in the above image), go to Part -> Create shape from mesh, leave the sewing tolerance as 0.1 default, and select “Okay”.

  1. Make sure the newly created part is selected in tree view.
  2. Go to File -> Export and save your STEP file.

Maybe the file is too large to process?

Meshmixer is the best reduction tool

Click on Import, Click on Select, double click your model. Now go to Edit and select Reduce.

It’s OK to leave the setting at defaults and click Accept.

Now export your reduced file.

We’ve run this reduction up to 3 times on one file and don’t see much loss of detail.

The file on the left is original at 24414 kb, the centre is one reduction 12207 kb and the right is two reductions 6104 kb

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Silk Look PLA Filament

Silky Figurine

Hello3D Silk PLAs produce impressive prints that are shiny and seemingly a bit translucent, giving them both the feel and look of being covered in silk. With this kind of filament, there’s no need to paint such prints, due to their natural appearance.

Hello3D “silk” filaments are enhanced PLA filaments, owing their glossy result to various additives. As such, they tend to show most of the same properties as PLA filament. In the case where silk filaments have a different base, these would be expected to have similar properties to the base material.

Please remember that print temperatures and speeds are a guideline and exact settings will be different for every machine.  We recommend that you print a temperature tower and stringing tests to find the best settings for you.

How to set your 3D Printer

Spool Net Weight:1kg

Diameter:1.75mm ± 0.05mm

Print Temperature:5°C lower than you print regular PLA

Heated Bed Temperature:50 – 60°C Print Speed:Nominal 50mm/s but use your regular PLA speeds

Shop the range now

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New Filament Stocks Just Arrived

Silky Filaments in a wide range of colours, gives a stunning finish to your designs, Silky Silver-Grey finishes chrome like, while colours like Silky Green, Silky Blue and Copper like are simply stunning. Fresh stocks of regular PLA colours, ABS, ASA and PETG have also landed.

PLA Copper Like.
Shop the range now

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Big Tree Tech TFT Stop Print Issue


If you use one of these screens, including the 24,35 or 50, and have recently updated the firmware, you’ll find that using the stop button during a print brings up a hung screen displaying “Loading” that can only escape by resetting your printer.

The fix is relatively easy, you’ll need to open the firmware in Platform IO via an editor like Visual Studio Code.

Open your firmware folder in Visual Studio Code, this will also cause PIO Home to open.

Expand User then API

Scroll down until you find Printing.C and select it.
In the righthand editor window scroll down until you find the section “Print Gcodes, in this version of firmware it begins at line 142, but may be different in your version. Use the find function to quickly locate it.

If you have affected firmware, under Case 0, Case 1 and Case 2 the command will show as mustStoreScript. You’ll need to change all three to mustStoreCmd as shown below.

Save the file, then run the build by clicking the PIO icon (Alien Icon), expanding the line that matches your screen and clicking build.

Now head to your firmware folder and navigate to the “Copy To SD Card” folder and open it. Copy the .bin file that matches your screen, config.ini to an SD card that is clean and formatted to Fat32. Open the Theme folder you’d like to use and copy the entire folder that matches your screen to the SD card. Power off your printer, insert the SD card and power on. The screen will update firmware and copy all the icons and fonts. All done, now the stop button will show loading until the printer stops and returns to home, but it won’t be hung.

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3D touch V3.0 Install instructions

3D touch V3.0 Install instructions

3D touch is a reliable lower cost alternative to Bltouch.

The first thing you’ll notice is the wiring colours are different to bltouch, other versions and brands of 3D touch. You can usually find the pinout marked on the printed circuit board of your 3d touch, you may need to remove the plug to see it. Once you can see the pin designation you can compare this to the colour codes on your cable.

The 3D Touch we use have the following designations,

Servo wires; Red 5V, Green Ground, Yellow signal

Endstop wires; Black Ground, White Signal

The 3D touch as shown below is setup from the factory to suit boards like SKR Mini, SKR 1.4, MKS Gen 1.4 and Creality. But you should always double check the pinouts as provided by the maker of your board.

To connect the 3D Touch to a board like SKR 1.3 you’ll need to change wiring order on the 3 pin connector. This is fairly easy, just gently lift the tabs on the black connector body (don’t bend the tabs too far back or they’ll break) and remove each wire. Make sure the tabs are pushed back down on the connector body and reinsert the wires as below.

The SKR 1.3 has the pins changed around compared to many other boards

Marlin Firmware Changes

As you’re Googling around you might find posts telling you to set ENDSTOP_INVERTING to true, this is incorrect, the setting must be false to make this probe work. If you get this setting wrong the printer will attempt to probe but the nozzle will hit the bed and the endstop will never trigger.

We’re going to run through the setup for Marlin 2.0, open configuration.h in your editor of choice and scroll down to around line 630 and check that ENDSTOP_PULLUPS are defined and that ENDSTOP_PULLDOWNS are disabled.

As mentioned above at around line 650 check that BOTH ENDSTOP_IINVERTING for ZMIN and ZMIN_PROBE are set to false.

At around line 835 check that Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN is defined.

Around line 890 check that DEFINE_FIX_MOUNTED_PROBE is commented out, especially if you’ve already been using another type of probe such as a P.I.N.D.A.

Around line 909 make sure define BLTOUCH is enabled

Around line 995 you’ll find define NOZZLE_TO_PROBE_OFFSET, take the time to measure these distances accurately. If the probe pin is to the right of your nozzle the value is entered as a positive such as 10, to left is entered as a negative such as -10. If the probe pin is behind your nozzle it’s a positive and in front is a negative. The third value on this line is Z offset, leave this as zero for now and adjust it in you printer’s config menu later.

Around line 1000 you’ll find define PROBING_MARGIN, you can leave this at zero but we prefer a bit of margin and set it to 10.

Around 1157 you’ll find define MIN_SOFTWARE_ENDSTOP_Z you can either disable all software min endstops or just comment out this line. This allows you to adjust a negative z offset which you will need for the 3D Touch probe.

Around line 1240 you’ll find mesh bed levelling, we use bilinear levelling. We’ve tried ABL but found it buggy. To use bilinear make sure define AUTO_BED_LEVELING_BILINEAR is uncommented.

Around line 1290 you’ll find define GRID_MAX_POINTS_X we like to set this to 4 which gives 4 rows of 4 probes, but you can set this lower. Be careful setting it higher as some 8 bit boards don’t have enough memory to store a large grid.

That’s it for configuration.h and these settings should have your 3D Touch working. Save the file and close.

There’s more settings in configuration_adv.h that we like to change.

Open configuration_adv.h and scroll to around line 660 you’ll find define BLTOUCH_DELAY the default value is 500, if you find your probe is ultra-reliable you can reduce this to a lower number like 300 or 200 or even comment it out altogether. Also around 669 you’ll find define BLTOUCH_FORCE_SW_MODE this can be useful if you are getting false triggering from your probe.

Around line 687 you’ll find define BLTOUCH_SET_5V_MODE, enable this if your probe is one of the newer ones and your supplier confirms it can run at 5 volts.

That’s it, run your firmware build and upload to your printer.

The probe should run a self-test at bootup and rest with a blue and red led lit.

If you have no lights, the three pin connector is wired incorrectly or plugged into the wrong port, double check your wiring and the correct pinout for your board.

If it faults and sits with a red led only, turn your printer off and check the 3D Touch pin, it should move freely, plus as you slowly push it up it should snap to the retracted position. If the pin is sticky unmount the probe and remove the top grub screw, take care NOT TO BEND THE PIN. You can then gently push it up with something small until you can grab and remove it. Carefully check the pin for any stray flashes of plastic. If you find any or even if a spot feels rough, gently remove the flash or rough section with a sharp blade. Go easy you only want to lightly scrape it until if feels smooth. Also check the pin is straight. You can gently straighten the pin if it’s bent, again go slowly and make gentle changes. You’ll have it right when the pin moves freely and it snaps up into place (with the grub screw reinstalled). Resist the temptation to prise the PCB off your probe, there’s nothing under there you can service.

If you issue a homing command and the probe continuously deploys and stows the probe (your printer may also display “Stopped”) then the probe is not sending the endstop pulse to the printer. You may have your white and black wires the wrong way around or you may have plugged into the wrong endstop socket, so double check your wiring.

Enjoy your new probe!