Capacitive Sensor

Controllers Smoothie
1

First off Happy Xmas all

I have just got the 2 sensors and would like some help with them.

First, which one would be the easiest to use ?
Can I use the 5v and wire them directly to the z min endstop ?
If they would not run on 5v input, what is the max voltage I can power them on direct to the board ?

here are the sensors I got.

LJC18A3-B-Z/BX NPN NO Capacitive sensor switch
Output: 3 wires, normally open
Current: 300 mA
Brown +
Black switch
Blue -

LJC18A3-B-Z/AX NPN NC Sensor Switch
Operating voltage: 6-36V DC
Output 3 wires, normally closed
Current: 300 mA
unsure but persume :
Brown +
Black switch
Blue -

many thanks

war

Imported from wikidot

2

Hey.

The endstop inputs on Smoothieboard are 5V-tolerant, and output 5V unless told otherwise, so you should be fine.

Cheers.

3

Hi Arthur

Thanks for your reply.

I used the BX version above and have it connected and working to the smoothieboard with 5v.
The trouble is that with such a low voltage the sensor gets to close to the bed before triggering, about 1mm .

I am going to use the 5v to try and get things working, but when i tried 12v the sensing was better at about 8mm.
Can i use a lm7805 or l7805 1.5a to reduce the 12v

Thanks

War

4

I think you need a voltage divider or something like that, search the forums, others have gotten it to work.

5

I got mine working last night using LJ12A3-4-Z/BX by wiring it directly to the endstop wires, although I am having issues getting it to work correctly as when I run a print it is adjusting to the point where one side of the print is barely on the bed and the other side is pressed in so hard that no material comes out of the nozzle on a 100 x 100 test square.
I am hoping that it is just the accuracy / repeatability of the sensor. I also have a LJ18A3-8-Z/BX but that one will not work just attached to the endstop power so I need to run 12v to it. To do that I will need to do what Arthurwolf said above and use a voltage divider. Toms Guide has a great explanation of how to do the voltage divider.

https://www.youtube.com/watch?v=EcGFLwj0pnA