Auto touch Z end-stop

Hi!

I made new Z end-stop.
After hot-end touches the bed - Z is stopped.
It better use with auto bed leveling in marlin firmware without any servo motors.

And works is great ! =)

[www.thingiverse.com]

Will this work on a Makerfarm i3, do you think?

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MakerFarm 8" Prusa i3v
RAMPS 1.4
0.4mm E3D v6 for 1.75mm

This is very interesting! Going to give this a go. Don't see any reason this wouldn't work on my MakerFarm i3. It's floating on a nut at the top now, so changing it to floating on a little platform at the bottom shouldn't make any difference.

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Currently printing on a MakerFarm Prusa i3. Curiously awaiting a PeachyPrinter.

Before everybody goes crazy for this - consider the accuracy. A normal microswitch has an snap action for a reason. A simple contact does not have that. You need very good contact repeatability to make the bed leveling work.

I'm not interested in it so much for the bed leveling, but for its method of keeping the nozzle from being plowed into the build plate. Once it touches, it stops, no extra force pushing it into the glass. It seems a safer method, to me, than a regular z-stop microswitch that might fail or be wired wrong.

Perhaps a hybrid might work better, uncle_bob? Have the X-axis floating on the platform like this, but with microswitches wired in series normally-open, closed by the contact with the platform, instead of the two contact pads?

Edited 2 time(s). Last edit at 01/08/2014 11:03PM by AbuMaia.

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MakerFarm 8" Prusa i3v
RAMPS 1.4
0.4mm E3D v6 for 1.75mm

Quote
uncle_bob
Before everybody goes crazy for this - consider the accuracy. A normal microswitch has an snap action for a reason. A simple contact does not have that. You need very good contact repeatability to make the bed leveling work.

That's a thought, there is no way it can be very accurate, but how about if a micro switch was incorporated in this design? That way we could have the best of both Worlds.
There would still be some fiddling around with the initial setup as there would need to be some compensation for the movement within the micro switch itself, but it will be repeatable each time.
Actually after thinking about it, the micro switch would be set mounted in/on the floating section
The micro switch wouldn't need to have the lever as well, that way the switch could be used as smaller in size and also the small snap action button could be made to touch the floating part and the new printed part (yellow piece) would just act as a plunger.
I see some others have also thought about a micro switch as well, guess that is good.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

My configuration for marlin

#define X_PROBE_OFFSET_FROM_EXTRUDER 0
#define Y_PROBE_OFFSET_FROM_EXTRUDER 0
#define Z_PROBE_OFFSET_FROM_EXTRUDER 0.4

Works stable with that result:

SENDING:G29
Bed x: 40 y: 40 z: -0.61
Bed x: 160 y: 40 z: -0.54
Bed x: 160 y: 150 z: -0.54
Bed x: 40 y: 150 z: -0.40
Eqn coefficients: a: -0.00 b: 0.00 d: -0.58
planeNormal x: 0.00 y: -0.00 z: 1.00
echo:endstops hit: Z:-0.40

And new video printing with auto bed leveling
[www.youtube.com]

Edited 1 time(s). Last edit at 01/09/2014 01:00AM by radus.

Hi radus,
I have some trouble on marlin setting.
Could you provide the marlin "Configuration.h" file?
Thank you a lot ~
BR
Asan

Ok, I've looked at thinguniverse and the videos, but I'm still a little confused about how this mounts and how to set the initial position. What is holding it in place? I saw something about a nut that the yellow piece holds. Is that nut there by default, or is it added just for this device. I don't have my printer kit yet, so I can't look for myself, but from images, it appears there is no nut there by default. But if there's a nut, then wouldn't the rotation of the threaded rod cause the yellow piece to move up and down as well?

Has anyone actually implemented this besides the author and can you share how you did the physical installation? Are there other instructions somewhere I'm missing?

radus, for us newbies, can you provide some detailed instructions for installing this piece?

Bruce

Edited 1 time(s). Last edit at 02/26/2014 04:51AM by brucehvn.

Normally there's a nut on the threaded rod inside the X axis motor mount and idler. What this object does is relocate that nut to the yellow piece. Yes, the yellow piece moves up and down the threaded and smooth rods. The X axis motor mount and idler ride on top of the yellow piece. When Z axis is moved down to zero, the extruder hotend will touch the build plate and stop, but the yellow pieces will continue to move down, opening an electric contact which tells the Z motors to stop. All you have to do is tell the printer to then move up some fraction of a millimeter to get to a good starting Z point.

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MakerFarm 8" Prusa i3v
RAMPS 1.4
0.4mm E3D v6 for 1.75mm

Quote
AbuMaia
Normally there's a nut on the threaded rod inside the X axis motor mount and idler. What this object does is relocate that nut to the yellow piece. Yes, the yellow piece moves up and down the threaded and smooth rods. The X axis motor mount and idler ride on top of the yellow piece. When Z axis is moved down to zero, the extruder hotend will touch the build plate and stop, but the yellow pieces will continue to move down, opening an electric contact which tells the Z motors to stop. All you have to do is tell the printer to then move up some fraction of a millimeter to get to a good starting Z point.

I see, thanks. I was under the impression that the stop was triggered by closing the contacts on the switch, but now from your description, the contacts become open when the bottom is hit.

Bruce