<p>Both diagrams are exactly the same, the difference is the +5 V that is not connected on the bottom diagram (displayed in white, labelled &quot;not used&quot;), but since your endstops do not have a +5 V pin in the socket (only ground, GND, and signal, SIG or S) you don't need to attach it. You should source the +5 V from elsewhere from your board. As the left and right side of the module are separated circuits, you need to power the board with +5 V.</p>
<p>Read <a href="https://3dprinting.stackexchange.com/a/10812/">this answer</a> for applying 24 V.</p>

CC BY-SA 4.0
2020-10-24T06:32:08.170Z
2020-11-17T09:33:17.563Z
2020-11-17T09:33:17.563Z
0scar
<p>I have <a href="https://m.de.aliexpress.com/item/32719957788.html?trace=wwwdetail2mobilesitedetail" rel="nofollow noreferrer">this</a> optocoupler.
<a href="https://i.sstatic.net/koQuA.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/koQuA.jpg" alt="optocoupler:" /></a></p>
<p>and <a href="https://www.aliexpress.com/i/32809655707.html" rel="nofollow noreferrer">this</a> sensor.
<a href="https://i.sstatic.net/4p8IT.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/4p8IT.jpg" alt="sensor:" /></a></p>
<p>I want to wire them together and use them for auto bed leveling. Note, stock Ender 3 board (Creality v1) has 2 pins for its endstop, not 3, so this:
<a href="https://i.sstatic.net/3jbKw.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/3jbKw.jpg" alt="dosent work:" /></a>
won't work</p>
<p>However, I found this diagram:
<a href="https://i.sstatic.net/EP9Vr.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/EP9Vr.jpg" alt="possibly might work" /></a></p>
<p>My optocoupler is rated for 12 V so I definitely wont attach 24 V to it. However, everything else seems good. So I could only replace the 24 V to 12 V and it would work?</p>

CC BY-SA 4.0
2020-10-24T11:08:26.920Z
Does this answer your question? [Inductive Sensor in 24 V machine?](https://3dprinting.stackexchange.com/questions/6358/inductive-sensor-in-24-v-machine)
Trish
<creality-ender-3><bed-leveling><electronics><wiring><inductive-sensor>
How to wire an LJ18A3-8-Z/BX sensor with an optocoupler to a stock Ender 3?
super autismo
# How to wire an LJ18A3-8-Z/BX sensor with an optocoupler to a stock Ender 3?

(Asked by: username_0 on 2020-10-23)

I have [this](https://m.de.aliexpress.com/item/32719957788.html?trace=wwwdetail2mobilesitedetail) optocoupler.
[![optocoupler:](https://i.sstatic.net/koQuA.jpg)](https://i.sstatic.net/koQuA.jpg)

and [this](https://www.aliexpress.com/i/32809655707.html) sensor.
[![sensor:](https://i.sstatic.net/4p8IT.jpg)](https://i.sstatic.net/4p8IT.jpg)

I want to wire them together and use them for auto bed leveling. Note, stock Ender 3 board (Creality v1) has 2 pins for its endstop, not 3, so this:
[![dosent work:](https://i.sstatic.net/3jbKw.jpg)](https://i.sstatic.net/3jbKw.jpg)
won't work

However, I found this diagram:
[![possibly might work](https://i.sstatic.net/EP9Vr.jpg)](https://i.sstatic.net/EP9Vr.jpg)

My optocoupler is rated for 12 V so I definitely wont attach 24 V to it. However, everything else seems good. So I could only replace the 24 V to 12 V and it would work?

**Tags:** creality-ender-3, bed-leveling, electronics, wiring, inductive-sensor
> **Comments:**
> **username_1**: Does this answer your question? [Inductive Sensor in 24 V machine?](https://3dprinting.stackexchange.com/questions/6358/inductive-sensor-in-24-v-machine)  

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## 1 answers

### Answer by username_2 on 2020-10-24. Score: 1 | Accepted answer

Both diagrams are exactly the same, the difference is the +5 V that is not connected on the bottom diagram (displayed in white, labelled "not used"), but since your endstops do not have a +5 V pin in the socket (only ground, GND, and signal, SIG or S) you don't need to attach it. You should source the +5 V from elsewhere from your board. As the left and right side of the module are separated circuits, you need to power the board with +5 V.

Read [this answer](https://3dprinting.stackexchange.com/a/10812/) for applying 24 V.


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