ANET A8 - BLTouch Auto leveling sensor

Brent Dowell

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So, The BLTouch sensor is different than the capacitive or inductive sensors. It uses a physical pin that extends and retracts to detect the presence of the bed.

51kS1h-fWmL._SL1000_.jpg

I used the mount from https://www.thingiverse.com/thing:1846913

I used the directions from https://www.thingiverse.com/thing:2091529

It's really not all that hard to get working, but you will need to upgrade your firmware to the latest version of Marlin in order to be able to use it.

The only real tricks with this is that it uses an unused pin on the lcd display buss. It's pretty easy though to just use an exacto knife to seperate the one wire from the unused led pin there and connect it up to the bl touch.

Now I can print on whatever I want, without having to readjust the z offset. Glass, the metal bed, tape, etc. I would only have to adjust things if I need to change out the hotend for some reason.

Here's a video of it doing the z level and bed leveling.

 
I've seen those advertised and was curious about them. Do you still have to determine an initial Z offset or does firmware determine that automatically?
 
You still have to determine the z offset, but in theory it's not as susceptible to temp changes, glass thickness, bed temp, etc...

I print on glass and am pretty happy with it, but in theory I could pull the glass off and put some tape down and print on that if I wanted and I wouldn't have to adjust the z offset.

I had an issue a while ago where my z offset was changing for whatever reason. Was giving me fits. Ended up being more related to my hot end being loose and clogged, but I had ordered this and figured I might as well make it work.
 
You still have to determine the z offset, but in theory it's not as susceptible to temp changes, glass thickness, bed temp, etc... ...

I've been pretty much satisfied with the inductive sensor I've been using, but have found that I really need to take the bed and hot end through a temperature cycle before committing to a print. Once I start printing, accuracy seems to hold the rest of the day. Saying that, though, I like the idea of a mechanical sensor, so will work toward that now.
 
I was pretty happy with my inductive capacitive as well, it just seemed to vary the initial layer a little bit every now and then.

I probably did this just more for the 'coolness' of it than anything else, lol.

(Darren reminded me that inductive is the kind that senses metal, capacitive the kind that detects other materials, like glass, or the distance to glass).
 
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