SFX-100 EMI Issues since adding 5th motor

Insr33 · May 25, 2022

Hey All

Was planning to post this in the main SFX-100 thread but given the fact that this problem is quite specific I've made a separate post. Tried to keep the post as clear as possible, here goes:

Problem:

Since I have added a 5th 90ST motor to accommodate my belt tensioner project, I'm in a loop of EMI misery.. The most striking fact to me is that I didn't have any issues prior to adding the 5th motor. After hours and days of troubleshooting, I'm still at square one. As soon as I activate the 5th motor my Valve Index produces grey screens as soon as I enter my rig (start driving) Unfortunately I don't have any pro electrical knowledge so forgive me my basic DYI skills

Hereby my setup / relevant info

Setup + relevant info:

SFX-100 motion platform (using the first revision of the motors (ver A)
VR set: Valve Index
Game: iRacing
Wheel: SC 2 Pro
Pedals: HE Pro
Powered USB hub connects wheel, pedals, simwind fans and shifter to main pc. My powered usb hub is below my pedals in a wooden box
Simwind arduino is in plastic box above the usb hub (I know this is very lousy solution but didn't find a suitable better solution yet)
Main pc on same power outlet as simrig because I only have 1 grounded outlet in this room

What happens (in detail):

When I use the SFX-100 without the belt motor turned on everything runs smoothly. I only get grey screens when I touch the headset (which is not really a problem to me) Problem happens as mentioned when the 5th motor is turned on and active in SimFeedback. Grey screens start popping up when I get near my rig and worsens when I start driving to the fact that it's unplayable. Problem does not worsen when I touch the wheel or the pedals which makes me believe my grounding is done properly. Also worth noting: my SC 2 Pro can get disconnected from the software where my only option is to restart the pc + wheel. I think this problem has worsened as soon as I have cable tied the SC2 pro cables. Need to test when connecting the wheel directly to the pc (in stead of the usb hub) Also worth mentioning: I hear a light electric buzz in my pc speakers when I launch Steam VR.

Things I have done / checked so far:

Added ferrite cores to usb's + valve index
Checked if my power outlet is grounded with a tester.
Grounded my wheel + pedals + simrig to the the Ground connector of 1 of the actuators. (using a wago connector to connect the differend grounding points - see picture)
Placed my Valve lighthouses at a different place. This made the situation a little better. In stead of continous grey screen it flickered a lot unplayable though
Installed a EMI filter + purchased a power strip which emi filter on board (no difference)
Wrapped my 5th actuator in copper tape: (Ordered some EMI shielding tape on Aliexpress but didn't had the patience to wait for it and ordered copper tape in the meantime) This made the situation a little bit better but it's still unplayable. I didn't tape my other actuators yet as I'm unsure if this will help (given the fact that my EMI issues don’t occur when my other 4 motors are running)

Grounding:

Belt Tensioner:

Box where my motors are placed, basically modified couch (old photo)

Rig Photo's (old without tensioner)

Have a nice day everyone

Any help would be greatly appreciated, thanks for reading !
If any info should be missing let me know

blekenbleu · May 25, 2022

Insr33 said:
Any help

Aluminum is unreliable for grounding.
Aluminum oxidizes almost instantly, and that oxide is an insulator.
Tooth star lock washers can pierce that oxide.
Power ground and signal ground are ideally separate.
Power grounds should all connect at a single point AKA star grounding.
That point would be the wall outlet.
Analog signal grounding (e.g. load cells, potentiometers)
should be separate from digital signal grounding (e.g. USB).
Shielding should be separate from grounding, except at a single point.
Your PC ties all the above together.
Connecting them together elsewhere creates ground loops.

DJ_Psymon · May 25, 2022

Try grounding the 5th motor from the mounting bolt.

Insr33 · May 25, 2022

@blekenbleu thank you very much for the info! I think I have to read up on the links you send to fully understand all the points you mention but I'll give it a go

I'll start by trying the star grounding in stead of the wago setup I use atm

@DJ_Psymon thx! very good suggestion, I'll test

JohnBeardmore · May 26, 2022

I was advised by a very knowledgeable electrical guy to take all the noisy grounds to a big copper stake hammered deep into the earth.

blekenbleu · May 26, 2022

JohnBeardmore said:
I was advised by a very knowledgeable electrical guy to take all the noisy grounds to a big copper stake hammered deep into the earth.

Since lightning takes paths of least resistance,
your sim rig becomes a lightening arrestor.

Insr33 · May 27, 2022

*update*

In the meantime, I have done some extra testing:
Also worth mentioning that I hear some light buzzing on my speakers when I start Steam VR

Wrapped another motor cable (from my SFX-100) in copper shielding. Unfortunately, this has not made any difference
grounded everything with the star method as indicated here (no difference)
grounded my belt tensioner motor (no difference)

blekenbleu · May 27, 2022

Insr33 said:
Also worth mentioning that I hear some light buzzing on my speakers when I start Steam VR

That could be a problematic PC power supply (filter capacitors with high ESR),
which could also be provoking Valve Index issues.
Wonky power supplies can generate all sorts of peculiar symptoms.

Steve D · May 27, 2022

You may have already done this but when I had grey screen issues with my Index with my SFX-100, I added this giant ferrite core and it resolved the issue immediately. Wound the headset cable through it five times, (just before the breaker box on the PC side) and have never had a problem since. (Using four motors / actuators)

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Lonnie Farrare · May 29, 2022

I had the same problem with emi when I initially incorporated the Index, my solve was in addition to the ferrite I wrapped the entire Index main cable with shielding tape. I keep the cable away from the actuators as well. Worked like a charm.

Insr33 · May 31, 2022

*update*

In the meantime I did some extra troubleshooting and got it (more or less) working! These are my findings

I changed my grounding from using Wago connectors to the star grounding method @blekenbleu suggested. I connected it directly to power outlet strip using this: https://www.amazon.de/-/en/gp/product/B0884598JW/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 This made the situation a lot better. (I could enter my rig without grey screens. However, when I started the sim they were back) Thank you very much Blekenblau this surely has lead to the partial solution!!
I wrapped all my cables with EMI tape instead of the copper tape I mentioned earlier. The combination of star grounding and the tape has almost completely removed the issues! I only get 1 single grey screen once in a while which is fine for me. However I'll keep apply some more suggestions mentioned by @Lonnie Farrare and @Steve D Thank you! Here is the link to the tape: https://nl.aliexpress.com/item/3262..._list.0.0.521779d2NB2UEj&gatewayAdapt=glo2nld
I also noticed my lighthouse tracking is a LOT more stable than before. I used to lose tracking completely once in a while. now it stays very solid
I still have the grey screens when I touch the headset. I hope this will be solved by adding ferrite cores / shielding to the cable
One very strange problem I have since adding the 5th motor are micro shifts of the index display when using the headset. Very hard to explain but it's like the screen keeps shifting a very tine bit each couple of seconds. Not very noticeable when driving but when I hold my head still and focus on one point you can clearly see the image shifting. So not to pleased with this extra problem but I'll do some more troubleshooting I guess

to conclude: Thank you everyone for the help / suggestions. It helped to keep my sanity in all of this

Steve D · May 31, 2022

Re. the micro stutters / image shifting, how close are your lighthouses to the rig?

When I first built my SFX-100 years ago, I had the same issues, incl. the occasional, jarring reset. I overcame this entirely by mounting the lighthouses up high, on ceiling support poles, one directly in front of the rig and one front-left, using adjustable camera clamps. Great thing about this solution is you can position them anywhere and tweak as required, assuming you have the space. Maybe, to start with, try moving them away from their current position to see if that makes a difference. Also, try plugging them in to a seperate wall socket as that helped others in the past. Would highly recommend getting that large ferrite core I mentioned earlier though because that entirely removed the grey screen issue for me, even when touching the headset.

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Insr33 · May 31, 2022

Steve D said:
Re. the micro stutters / image shifting, how close are your lighthouses to the rig?

When I first built my SFX-100 years ago, I had the same issues, incl. the occasional, jarring reset. I overcame this entirely by mounting the lighthouses up high, on ceiling support poles, one directly in front of the rig and one front-left, using adjustable camera clamps. Great thing about this solution is you can position them anywhere and tweak as required, assuming you have the space. Maybe, to start with, try moving them away from their current position to see if that makes a difference. Also, try plugging them in to a seperate wall socket as that helped others in the past. Would highly recommend getting that large ferrite core I mentioned earlier though because that entirely removed the grey screen issue for me, even when touching the headset.

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Shop Bessey ST250 ST Telescopic Drywall Support, Grey, 2500 mm. Free delivery on eligible orders of £20 or more.

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Thank you again Steve for the feedback. The lighthouses are 3 meters away from the rig (the first one is marked on one of my photos in my initial post) As you can see the first one is on the back side of a couch so not really a sturdy underground. I'll try your suggestion to get them in the air and solid mounted + other wall socket. Regarding the ferrite core: Would you happen to know (or link?) what the diameter is of the ferrite core you ordered? To be sure the ferrite core needs to be added here?

Steve D said:
this giant ferrite core and it resolved the issue im

Steve D · May 31, 2022

The link to the ferrite core is in my earlier post but here it is again. Yep, I wound the headset cable through and around it, (it unclips to make it easier) and just before the connection shown, on the PC side. Managed about 5 turns. (The ferrite is larger than it looks)

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TheTarman · Jun 9, 2022

Steve D said:
The link to the ferrite core is in my earlier post but here it is again. Yep, I wound the headset cable through and around it, (it unclips to make it easier) and just before the connection shown, on the PC side. Managed about 5 turns. (The ferrite is larger than it looks)

0431177081 Fair-Rite Products Corp. | Filters | DigiKey

Order today, ships today. 0431177081 – Hinged (Snap On) Free Hanging Ferrite Core 375Ohm @ 100MHz ID 1.010" Dia (25.65mm) OD 2.220" W x 1.080" H (56.39mm x 27.43mm) Length 1.690" (42.93mm) from Fair-Rite Products Corp.. Pricing and Availability on millions of electronic components from Digi-Key...

www.digikey.co.uk

I can confirm this ferrite core cable wrapping works.
I've had been suffering from EMI issues for a while; gray screen when touching the headset, or the lighthouses would completely lose tracking when I turned on the rig.

I wrapped the VR headset cable around the core 6 times and I could then touch the headset without gray screening. Tracking was spot on. I was super happy.

That said; the problems seem to be coming back, for unknown reasons.
I recently moved a lighthouse to above the rig, which I'll move again, but the wheel is also randomly cutting out mid race which its driving me nuts, along with the people I'm crashing into.

Insr33 · Jun 20, 2022

I have the same issue. My wheel (SC2 Pro) is disconnecting mid game or has short disconnects. This was happening after I tucked away my usb cable in my 80/20 profiles. As soon as I "draped" the cable directly from my pc to the wheel this issue was gone. I need to investigate further (other cable, .. ) to know how I can solve the issue with correct cable management. If somebody should have another link to the ferrite core mentioned let me know (Europe). It's quite expensive imo with shipping