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Help with probing: Arduino / GRBL / Openbuilds Control

Discussion in 'Controller Boards' started by sharmstr, Feb 26, 2019.

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  1. sharmstr

    sharmstr Master
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    Hey Guys,

    I'm having some issues with probing a touch plate I milled yesterday. I have one wire connected to the plate which goes to A5 on the arduino. The other wire is attached to the bit via an alligator clip which leads back to ground on the arduino.

    Using OB Control, the probe triggers instantly without even moving. I checked the troubleshooting tab and the probe show closed until I touch the alligator clip to the plate. So that seems fine.

    While testing, I noticed if I have my drivers powered OFF, then the probe routine acts like it wants to work (no instant trigger).

    This leads me to believe its a noise issue with the motor drivers (DQ542MA's), but its strange that the probe troubleshooting light seems to work as expected with no false triggers.

    Any advice on how to troubleshoot this? Thanks!
     
  2. Rob Taylor

    Rob Taylor Master
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    You don't have a stray ground somewhere through the machine? Seems more likely than noise coming from a shielded board.
     
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  3. Giarc

    Giarc Master
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    I have mine configured the same and I use the DQ542MA drivers as well and have not had issues with noise. It worked with GRBL Panel and now with Estlcam. I wonder if potentially there is an issue with the wiring. I have yet to try the OB Controller. I plan to use it with my next build, though.
     
  4. sharmstr

    sharmstr Master
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    I did some more testing and was able to get it to work as long as the touch plate was 1 foot away from the machine. LOL
     
  5. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Try adding a 10k pullup resistor to 5v onto A5 - to keep the plate "HIGH" until Grounded. The Arduino internal pullups are very weak
     
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  6. Giarc

    Giarc Master
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    That is interesting. The more I read about strange issues people have, the more I think any success I have had with things is entirely based on luck. :)
     
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  7. sharmstr

    sharmstr Master
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    That did it! Thank you! :thumbsup:
     
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  8. John Davies

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    Thanks for the info. I tried a 10k resistor but I am still having issues with the probe stopping about 1/4" away from the touch plate. Can you please tell me the pins on the arduino you are using to connect the resistor to. Thanks, John.
     
  9. sharmstr

    sharmstr Master
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    As Peter said above "5v onto A5 ". A5 is your probe pin.
     
    #9 sharmstr, May 21, 2019 at 11:08 AM
    Last edited: May 21, 2019 at 11:57 AM
    Peter Van Der Walt likes this.

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