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I’ve got this proximity sensor which is a 5 V, it doesn’t say it can be used over 5 V. Can I use a buck converter or is it possible to wire it up direct to a 5 V source on the Ender 3 V2?

What I don’t understand is where to wire it direct to 5 V on the printer or if I use a buck converter then where does the 3rd wire go to on the printer? If it goes to the signal wire on the Z endstop then which one is the signal wire?

enter image description here

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    $\begingroup$ Welcome to 3D Printing SE and thank you for your contribution. When you get a chance, please take the tour to understand how the site works and how it is different than others. $\endgroup$ – agarza May 9 at 3:53
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That part seems dubious

Your part is labeled LJ18A3-8-Z/BX. That is a Z/BX type sensor of the LJ18A3-8 series - that first part dictates an M18 outer thread and thus dimensions and a triggering distance of 8mm. Z/BX indicates NPN NO, so a normally open sensor of the NPN type. However, that labeling indicates an inductive sensor with a required supply voltage of 6 to 36 V and a power draw of 10 mA between the supply and ground line and a digital output signal of 300 mA.

There is a variant in existence, that has a 5 V supply voltage, but its part number is different by 3 characters: LJ18A3-8-Z/BX-5V - the appended -5V is crucial to show it differs from the standard!

The Ender-3 Board

The Ender-3 board has a 24 V input from the power supply and runs its end-stops on 5 V logic. That would suffice to connect the output of a LJ18A3-8-Z/BX-5V sensor directly to a sensor pin.

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  • $\begingroup$ Hi I did test it with 5 V source and see if the led comes on near a metal object, and it does and it seems bright, there’s 2 wires going to the end stop and I was wondering how to wire it up? $\endgroup$ – Imran Ali May 10 at 15:12
  • $\begingroup$ @ImranAli then the part is mis-nomed, for wiring it up, you should test the output voltage on the other wires on 5 V input $\endgroup$ – Trish May 10 at 19:36
  • $\begingroup$ There’s quite a lot of sellers selling them and they all say 5 V on the label on lots of websites , so I’m presuming it Is 5 V and most 6 V onwards won’t even work at 5 V but this does actually work at 5 V. $\endgroup$ – Imran Ali May 15 at 14:02
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    $\begingroup$ @ImranAli I would suspect this is the 6V-36V version and the sellers are stretching the truth a bit by claiming it (also) works at 5V. A sensor designed for 6V probably also works at 5V but may or may not be reliable. $\endgroup$ – Tom van der Zanden Jun 8 at 12:38
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The schematic attached to the cable shows the wiring for the sensor. There is BN+, BK, BU-; these are presumably the brown, black and blue wires respectively. The schematic BN+ is the positive supply wire (should be connected to 5V) and BU- the negative wire (should be connected to ground). BK is the output wire and should be connected to the endstop signal pin.

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