Possible EMI Interference - Shapeoko 4

Hi folks,

I’m new to my Shapeoko. I “made my bones” on a 3018 pro for a few years and have only used cncjs as that suits my setup the best.

I have a wifi router in the basement but it in the front partition, separated by wooden walls from the back where my small SBC machines are wired with their wifi disabled.

Recently, I added a j tech laser to the machine. If you are not familiar, it disconnects when you want to use the router.

I didn’t have a spare x86_64 machine to run Lightburn and brought down an older laptop to run Lightburn temporarily. It sat close to the machine on a chair.

When I switched to the router to do another job, I left it there. The probe macro for the bitzero skipped the step where the bit retracts in the Z direction and there went my 1.8mm. (I have several, yes I should have used the bitzero “rod” but oh well)

When the job ends, I have cncjs send an mqtt packet to turn off the tasmota outlet for the router. This also failed, first time. (Not the first time I murdered a bit in a probing attempt :slight_smile: )

I can’t help but think that the laptop was to blame.

My plan: use a hack to share my USB port over TCP to my odroid h2 near my work bench and use Lightburn from there when I need to.

I have gotten this to work with ser2net on the rpi and socat on the “client” and will post a cookbook if anyone cares and could make it this far in my post.

Has anyone experienced anything similar? I’ve dealt with ground loops before and my cell phone makes my PC speakers sound like a Sci Fi movie but otherwise I am unfamiliar with this.

Usually when this arises after a period of successful operation it’s either the carbon brushes in the router wearing down, or the humidity lowering as the seasons change.

This makes sense, it’s just that I have been running jobs without a hitch for a few months (not a large amount, only one or two a week since the end of the summer). This is the first time I had issues and the laptop is the big change.

All are plugged into the same power source and the plug tester from home Depot shows good wiring, if that is indicative of much.

The bitzero probing was run when the vacuum was off. I take the bottom half off of sweepy when zeroing the bit, but I suppose there may have been a charge beforehand.

Thank you for your input.

The other thing that changed was that I surfaced a charcuterie board with an epoxy inlay. Perhaps the shavings caused the static electricity? They certainly clung to my vacuum hose, and it isn’t grounded.

I’ll take a closer look at all of it when I return home in a few days.

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Replying to myself here with more background information.

I live in a swampy area and the basement humidity rarely drops below 45%. Static electricity is not really an issue here as I have 2 dehumidifiers that fight together to keep it that low.

So it may be happening locally in the hose but I haven’t had the experience of a shock from touching a doorknob since moving here 30 odd years ago. One can break a sweat just crossing the lawn to get the mail.

Looking at other posts, I should fill in wiring details. I cut a 15 foot 12 awg extension cord to connect to a estop to power a standard power strip that feeds the carbide 3d router and Shapeoko. The extension cord is stranded wire so that might not help, and the length, but it does connect to a 20 amp circuit.

Edit: the cord may have been marked in Ampere rating, not gauge.

The laptop did plug into that power strip and I hadn’t done that before. The shop vac is plugged into another breaker.

I have a 20 amp wire over the CNC that I could tap into as well for a new outlet, and I have been considering this since I purchased it in August. Then I could reduce the length of the cord.

Also the power strip has a longer cord and as I type this, I can’t help but think that this also needs to be replaced.

I am an amateur DIY person with stronger software skills than hardware. Any thoughts are greatly appreciated.

Thanks for listening.

The big thing I’d try would be an EMI filtering power strip:

(maybe get one with a long enough cord?)

and arrange the cords as far from each other as the space allows.

The other big thing to check is the grounding — make sure it’s in a star topology to/from a common ground and that there aren’t any ground loops — if you don’t have a conductive/static dissipative hose then run a bare copper wire through it from end-to-end and ground it to the ground the vacuum is plugged into.

Thank you. I will try the power strip.

The hose is about 20 feet long. The copper wire should be bare, I suppose, as others have done here in the forum. It seems logical, but I just want to clarify.

I would rather not strip that from a length of household electrical wire but I can get some solid core lower gauge wire from the hardware store. I might have some around the house somewhere but I doubt I have that length.