Hello,
My name is Thor and I was wondering if I can achieve the same function as this 12V 1 Channel Optocoupler Isolation Module Isolated Board No PCB Holder K9 (L50 (12V 1 Channel Optocoupler Isolation Module Isolated Board No PCB Holder K9 ( L50 | eBay)
with this Opto-isolator Breakout SKU: BOB-09118, and how would I wire it up.
The reason I need this is to control the voltage of an inductive sensor for a 3d printer, this video describes in more detail what I am trying to achieve. (https://youtu.be/NROBJ8rbNw4)
If I can provide more info please ask.
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Hello Thor, Welcome to the forum,
As best as I can tell it looks like BOB-09118 is only a 5V input optocoupler so it won’t help if you want to connect a 12volt sensor.
If you are using the sensor purely to get a limit reached/not-reached digital input you could consider using a relay. An optocoupler is awesome because it is electrically and magnetically de-coupled, but in this circumstance you are mostly just using it to convert your sensor output level from 12V to 5V.
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Hi Trent,
Thanks for the reply, the npn inductive sensore is 6 - 36v and the board can handle 5v max. The first board I used a buck step down converter and it worked well but the new board is not liking that option. Are there any option availble on core electronic I could look.
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Hi Thor,
Could you send through a datasheet and some more information about how you are using the inductive sensor? I’m just trying to understand if it is sending back a range of analog measurements or just a true or false threshold reached type of output.
Buck converters are fantastic for lowering the level of a power supply down to something you can use more easily but their biggest disadvantage is the huge amount of switching noise they can bring into your circuit which may intefere with other components like your inductive sensor.
2 Likes
I found two, Im not sure if its enough info for you. I tryed the option with the resistors but it didn’t work as the voltage drop wasn’t enough for the SKR v1.4 board to trigger. Currently I have a diod attached in reverse on the sensor wire which allows me to use the pull up resistor (can’t remember if its pull down) to use the sensor, because of this I think its causing an inaccuret reading with the sensor.
LJ12A3-4-Z Datasheet.pdf (52.7 KB)
NPN SENSOR LJ12A3-4-Z datasheet.pdf (1.7 MB)
2 Likes
Hi Thor,
Thanks for sending those datasheets through, it looks like the prox sensor output is a 300mA sink that is triggered when it detects something within 4mm.
I believe this means it is an active LOW signal when triggered and will require a pull-up resistor installed between the output and a positive voltage rail.
The sensor will then output 0 volts when triggered (object <4mm) and the positive voltage rail level when objects are not detected.
Worth mentioning, if this is for 3d printer bed leveling, is there a reason you couldn’t use something like the BLTouch?
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I will node and pretend I full understand everything, I did think about the bl touch but for $50 and above price point it turned me off. I was using a basic melzi board with a atmeg 1240p chip and it worked rely well. I can try the 100k and 150k resistor option again but the volts we’re not droping enough. I like the idea of buy ozzy for speed and support like this, as I can do most things that need to be done (youtube us a wonderfull thing)
2 Likes
Hi Thor,
The absolute cheapest bed levelling option if you’re running Marlin is Manual Bed Mesh Levelling. I use it at home and it gives great consistent adhesion. Teaching Tech has a fantastic video on this:
Another thing to consider is making sure that your bed levelling springs are strong enough to provide enough friction to stop them moving around. I upgraded mine on my Ender 3 V2 and it helped it stay level between prints.
Good luck with your printing!
-James
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