GRBL Auto Leveling?

MeanderBolt
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Re: GRBL Auto Leveling?

Post by MeanderBolt » Mon Mar 23, 2015 10:43 pm

Hey reganissu, I had the same issue and found that it was a noise issue (my post of nearly the same thing). I found several threads about circuits for killing off the noise. Once it was built I had very accurate 'touches' in CP.
Have a read through THIS thread. On page 4 there is a schematic I used which seems to be working well. I made a whole board of em so if I ever get around to finally putting on my end stops, I am ready.
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aiden1015
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Re: GRBL Auto Leveling?

Post by aiden1015 » Mon Mar 23, 2015 11:17 pm

Scott216,

Thank you so much, that really clears up a lot for me. Are there any options to do multiple passes to cut the board out?

reganissu
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Re: GRBL Auto Leveling?

Post by reganissu » Wed Mar 25, 2015 3:38 pm

Postby MeanderBolt » Mon Mar 23, 2015 11:43 pm

Hey reganissu, I had the same issue and found that it was a noise issue (my post of nearly the same thing). I found several threads about circuits for killing off the noise. Once it was built I had very accurate 'touches' in CP.
Have a read through THIS thread. On page 4 there is a schematic I used which seems to be working well. I made a whole board of em so if I ever get around to finally putting on my end stops, I am ready.
Hi MeanderBolt,
thanks for the tip about the noise issue. I was thinking about wrong hardware setup/wrong software workflow/wrong shield interface issues, but I think you are right, I have a noise issue.
I have read through the thread you suggested, thanks again: that has led me to breadbording the same circuit you and scott216 made in the thread, using the same values of yours about that circuit components. I used your values because all the thread is about cleaning limit switches signal (which I have to mount, and I am delaying that a bit too.. ;) ), while I was interested in cleaning probe signal, as you were.
Image
I gave that a try probing with autoleveling in chilipeppr and as a result the SO2 behaved without any noise issue, , but instead had a no signal issue. As a matter of fact the probe did not trigger at all and I had to manually stop the SO2 because it was going down risking to break the copper/the milling bit - by the way i was doing this test with a ball nose carbide mill from dremel in place of the frail v-engraving bit.

So I tried to figure out what was wrong with my setup and I am thinking that could be the pull up resistor value too high, because (i am guessing - sorry I am no expert) it sums to the resistance of the wire that goes to the probe + the copper + the wire that comes from the copper + connection in the breadboard = a too large resistance issue on a internal pullup input pin, as described here
I am going to try with a lower pull-up resistor to check if I am right
I have also to upload a little clear schematic of what I am doing with the breadbord, I think someone with a little electronics experience could easily solve my issue.
ciao
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reganissu
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Re: GRBL Auto Leveling?

Post by reganissu » Fri Mar 27, 2015 10:12 am

reganissu wrote: I gave that a try probing with autoleveling in chilipeppr and as a result the SO2 behaved without any noise issue, , but instead had a no signal issue. As a matter of fact the probe did not trigger at all and I had to manually stop the SO2 because it was going down risking to break the copper/the milling bit - by the way i was doing this test with a ball nose carbide mill from dremel in place of the frail v-engraving bit.
Hemmm ... I made a big mistake, my 5v cable was not the right one, so the breadboard was powerless and that's the silly reason of the no-noise no-signal result.


So I linked up the right cable and got back to the old issue: now I have again the noise triggering signal MAYBE.
Tried some different values for r2 (low-pass filter resistor) and also for r1 (pull-up resistor), with no luck.

Then I did a try that put me even more in doubt.
I tried to disconnect all the cables except two short ones soldered to A5 input pin (probing pin on grbl 0.9) and the other to arduino ground. The other side of those two cables has been left disconnected . Then I runned autoleveling on chilipeppr and had the same issue (thought it made a little more probing).

So it's really still a noise issue (from two hanging cables??) or what else can be wrong ?
I'm still in doubt that I am trying a schematic that is good for normal input pin on arduino (like limit switches ones) but not good for an internal pulled-up input pin (like the a5 probing input of grbl 0.9)
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scott216
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Re: GRBL Auto Leveling?

Post by scott216 » Fri Mar 27, 2015 12:49 pm

Try putting a pull up resistor on A5. Something between 300 and 700 ohms
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reganissu
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Re: GRBL Auto Leveling?

Post by reganissu » Fri Mar 27, 2015 3:42 pm

scott216 wrote:Try putting a pull up resistor on A5. Something between 300 and 700 ohms
Hi scott216, thanks for the tip, I tried that in various configuration

- ground wire disconnected, (my machine stops probing very early, so i thought I can simulate probing touching with ground wire the sensore wire, just to narrow the issue to the simplest circuit possible) sensor wire pulled up with 220 ohm, then 440, then 880 = failed as before

- then I applied the same tries with resistor to the circuit you made, and also MeanderBolt used here = no success again

lastly I tried to copy the circuit they use in tinyg to filter, from here (they wire sensors with 3.3 v logic, though, so I stuck with our old values on components)

I am about to check tinyg early schematics (before v7) in which they use internally pulled up pin. I think if I cannot get any luck here, maybe I can enter autoleveling heaven changing my board, maybe to something like this http://www.ebay.com/itm/CNC-5-Axis-Brea ... 3641.l6390 - that would defenetly put me off this thread :|
Shapeoko 2 with 1000mm xrail, makita router
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reganissu
Posts: 24
Joined: Fri Jun 27, 2014 12:18 pm

Re: GRBL Auto Leveling?

Post by reganissu » Fri Mar 27, 2015 3:56 pm

mmh early tinyg schematics are not on github, electronics substitution is coming...
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Prusa I3, 3D printer

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