[vincentP]

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

[vincentP]

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 4 years, 8 months ago by vincentP.

[vincentP]

Thanks

I’ll confess to very busy duty cycle, but my studio is not warm at present.

I now have spare parts with which to make a ventilated servo case if you think that would help :-)

The raspberryPi has a touch screen, so both the pi and the touch screen are powered off usb ports built into a power strip. The Axidraw is powered by a two prong wall wart plugged into the same strip. The wall wart is not polarized.

The pi is also connected to an ethernet hub, which is on a different power strip. I can print with the ethernet disconnected if necessary.

[vincentP]

Dead servo again.

So I have maybe twenty hours total run time on the Axidraw before the servo died.

To be clear, that’s twenty hours of servo run time.

Maybe ten hours of a single continuous plot.

Is it possible that the belt is building up static charge when running continuously?

I ask because it has quit twice when I touched the usb cable after the plotter had been running for many hours.

(Touched, not wiggled.)

Is twenty hours of run time anywhere near the life cycle for these servos?

If not I’ve got something else going on.

I’m inclined to try grounding the Axidraw to the Raspberry Pi to see if that makes any improvement.

[vincentP]

Replaced the pen lift servo.
Working properly again.

Thanks for the quick turnaround on that.

[vincentP]

Connected axidraw to laptop running inkscape.

Everything works except pen up / pen down.

This looks like bad servo.

[vincentP]

The obvious approach, connecting the axidraw back to my laptop, did not occur to me. I’ll try that tomorrow.

Pretty sure the “failed to connect” issue was a bad usb cable (a working cable that died while I was using it).

If pen up and pen down were somehow set the same, would “toggle” show movement?

[vincentP]

Well, I’m back.

The servo has apparently quit completely.

Is there a way to test this?

“Axicli -m toggle” no longer moves the pen (it did for a while).

I might get a prompt back immediately as if it had worked, or I might get a “failed to connect to axidraw” message after a bit of a wait.

I had one sketchy usb cable, but replacing it (with several different cables) has not gotten the servo to move.

So, it does not respond to “axicli -m toggle” and it does not respond when attempting a plot, that is, the pen holder runs around the paper as expected when plotting but the pen does not move up or down where I would expect it to.

Dead servo? Is there way to test other than “toggle” ?

And separately: the toggle command solves my issue with adjusting the pen, but earlier attempts to get axidraw extensions installed in inkscape on raspian suggest that this may be difficult, if not impossible.

Commands to update and install inkscape thinks an old inkscape is current, and my attempts to install from a personal repository suggest that raspian won’t recognize the commands to do that.

The command line interface seems to meet all my needs so far, but someone else down to line might get frustrated by this.

[vincentP]

Thanks again.

“Toggle” is further down the page than “pen_up”
I stopped reading at “pen_up”

🤡

[vincentP]

Thanks That’s what I figured was happening.

I wasn’t sure if I should start a new thread for the pen up / pen down stuff:

I can’t control the pen up / pen down from the cli using raspian on a raspberry pi.

“Axidraw -M pen_up” requests a filename in order to work, but when I include a filename, it tries to plot the file (as you might expect). Same with pen down. I just want to adjust the pen height without moving the pen from home position.

I suppose I can install Inkscape and axidraw extensions on the pi and adjust from there, but that has its own set of self inflicted problems:
I won’t muddy the waters with those issues here.

[vincentP]

Well, the offending plot printed today in something like seven hours.

So, I assume it was not a timeout problem.

That pretty much leaves the warped paper, but also the fact that I switched from plotting from Inkscape to using the command line interface.

I’m reasonably sure that the pen up and pen down positions, as well as a few other relevant settings, are not the same when I send the plot from the CLI as they are when sending from Inkscape.

That, combined with the paper issues, left the pen off the paper for part of the plot.

[vincentP]

Thanks

Magnifying glass shows a continuous line of joined circles kind of like cursive script, so timeout may be a factor, along with non-flat paper.

[vincentP]

Oh, it looks like my fault.

The paper isn’t flat, so the pen prints on the high part and misses the low part. (But the servo looks like it’s “up”.)

The difference between “high” and “low” is very small, but just enough that the pen clears the paper in the low part.

Because the plot is lots of small marks close together, the pen stays in the sme area for a long time, so I didn’t realize what was happening.

I think that’s the answer.

I’ll try the plot again with properly thick and smooth paper and expect it will be fine.

It’s easier to see that the pen doesn’t touch the paper than to see that the paper is wavy.

Mea Culpa

[vincentP]

Hey, maybe it is the timeout.

The thing has been plotting for a while now and I noticed that while it’s making lots of little squiggles, it’s not lifting the pen between them.

Also, the servo motor is cool to the touch.

[vincentP]

It’s printing now.

I’ll let it run overnight and see how it looks in the morning.

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