Pen lift problem

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  • #28325

    This may just be a bad servo, but I’m having a problem getting my pen off the page.

    It comes up for some stuff, but not for others, so the servo isn’t dead, but it’s behaving badly. I don’t know if that’s the servo’s fault or not.

    I am using the command line interface from a raspberry pi 3b.

    Axicli filename.svg -L2 -d40 -u55 -Z 200 -C

    So, constant speed with 200ms delay on pen up, with what I hoped would be limited travel on the servo arm.

    The servo arm swings almost 180 degrees, which is where the pen lift failure is happening.

    I had hoped the -d40 -u55 would constrain its motion, but it doesn’t seem to.

    Also the servo arm bounces back and forth in the downward position, in what I imagine is the difference between the -d40 and -u55, but in the wrong orientation with respect to “up.”

    Is this just a bad servo? If so, no big deal. If not, where should I look?


    Windell Oskay

    Is this one of our servos that came with the arm pre-attached, or is this some other servo?


    It’s a replacement servo that came from you, and that I installed, but has been working fine.

    If this should matter, I have more than one raspberry pi, and this axidraw is now attached to a different raspberry pi than it was previously.

    I have not created any config files on the rpi

    • This reply was modified 3 years, 7 months ago by vincentP.
    Windell Oskay

    My initial guess is that this could have been a “mis calibrated” servo, with the arm at the wrong angle, but since it’s one of ours, I would now suspect that it is just a bad servo. If so, please contact customer service via email for a replacement.

    One other thing to check, if you are able to, would be to try raising and lowering the pen between those same values from within Inkscape (ideally on a desktop computer). If it still fails in the same way, you can be sure that it’s a matter of hardware failure rather than of something in the software setup or parameters in the CLI.


    Well, it had been working, so I figured it might be the servo, and your above test confirms it.

    I connected to a MAC book pro with Axidraw extensions in Inkscape, and when I tried to toggle the servo once, it goes up and down repeatedly non-stop until I powered off the Axidraw.

    I’ll send for a new servo.

    Thank you

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