mkeeley

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  • December 23, 2018 at 5:57 pm in reply to: TinyG v7 very sensitive to noise/emi? #11258
    mkeeley
    Member

    Hmm, bit small. If you open the images in a new tab you can read them more easily.

    December 23, 2018 at 5:56 pm in reply to: TinyG v7 very sensitive to noise/emi? #11257
    mkeeley
    Member

    Many thanks for your help.

    Here is my machine: 🙂
    Overview
    Zoom
    Hopefully you can see the annotations on the image.

    I built it as an experiment from DVD & Floppy drive mechanisms. It’s also kind of a test to see if I can get the TinyG working with Chilipeppr before I embark on buying a bigger machine (probably a 3020 from AliExpress/Ebay).
    i.e. If I can get the noise problems sorted.

    More details:
    Back Connections
    Zoom
    Back Connections
    The E-Stop is the only one configured as a limit.

    TinyG
    Zoom
    TinyG close up

    Switch
    Zoom
    Homing switch example

    I will try your suggestions and rewire the switches with better cable.

    Do you think connecting the base plates of the drive mechanisms to ground (or the shield wire perhaps) would also help?

    • This reply was modified 5 years, 10 months ago by mkeeley. Reason: Added image links
    December 23, 2018 at 6:22 am in reply to: TinyG v7 very sensitive to noise/emi? #11255
    mkeeley
    Member

    yes, unused switches are off. I have 3 set to homing only (xmax, ymax, zmax) and 1 set to limit only (amin) – this is my emergency stop button. They are all NO switches, and that is how I have configured the tiny ($st=0).

    Regarding twisted pair – I can’t see how that would help, as twisted pair is only useful with differential signals (i.e. Data+ / Data-).
    My connector is shielded, but with several connectors running through it (8 core cable). The shield is connected to ground at the board, and each limit switch uses one of the connectors, ground uses one, and three are left unconnected.

    I have some electrolytic caps, I’ll try adding those.

    Do you think the unconnected wires in the cable would cause an issue?
    What about adding the caps at the switch end?

    February 28, 2013 at 6:59 pm in reply to: Can't set switch to limit mode #3827
    mkeeley
    Member

    Thanks Alden, that did the trick.

    One thing I noticed was that the verify fails after programming (using Studio6 + AVRISP mkII):

    10:53:37: [ERROR] Verifying Flash…Failed! address=0x17c00 expected=0x38 actual=0xff

    But the compile etc was all OK, and the tinyg seems to work! Maybe this is the bootloader address, and some bug in atmel studio?

    I usually use AStudi04 and avrdude, but I couldn’t seem to get avrdude working.

     

    And yes, I’m aware of the NO switch noise issue; I’ve built a micro-cnc out of old DVD and floppy drive innards http://tinypic.com/r/nofyw3/6 (insipration from hack-a-day: http://hackaday.com/2010/11/08/cnc-machine-from-pc-parts/) so I’m hoping it won’t be too much of an issue. Very low current.

    The limit/homing signal cable is shielded, the wires from the junction box to the switch was supposed to be shielded also (they are wires from an old headphone set), but it turns out they weren’t after I cut into them :-!

    I’ll make a full write up later.

    Mike.

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