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Passive Seat Belt Tensioner 2.0 for the SFX 100

Discussion in 'Sim Racing Hardware' started by HoiHman, Jun 2, 2019.

  1. HoiHman

    HoiHman
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    This weekend i added a passive seat belt tensioner to my SFX100 rig.

    A couple of months ago i tried to do the same, but it did not give me the result i wanted. You can read all about that here.

    https://www.racedepartment.com/thre...oner-with-simtools.163727/page-3#post-2916042

    There were 3 things i did not like about my first attempt

    1. The seat rear belt at the back is being pulled down under braking. This results in a downward pressure on your shoulders and i could not match that feeling with brake forces you experience in real life.
    2. To get an reasonable amount of pressure, the initial spring tension already needed to be fairly big, resulting in a uncomfortable pressure on my shoulders in the rest position
    3. It added unwanted additional "set-up time" since i have a mobile rig.

    So initially i aborted the idea of a passive seat belt tensioner and decided to wait for the second controller support to build an active version.

    In the topic above i already mentioned that, in my opinion, that tensioning the lower belt is more immersive. I believe that under braking you want the surge feeling coming from the front and not the back. Ideally, you would have all 4 belts being pulled back under braking.

    With second controller support being officially announced i started to look a how i might implement this and already ordered some extra belt to start experimenting.

    https://nl.aliexpress.com/item/Poly...756.html?spm=a2g0s.9042311.0.0.e60b4c4d0p0Fk2


    Yesterday the belt arrived i decided to test my theory of tensioning the lower belt being more immersive first, before started to work on the design.

    I tied the extra belt parallel to my seat belt fixing point and put the other end under the rear feet of the SFX100. I did some testing and adjustments, after a while I loved it so much, that i aborted the idea of an active seatbelt tensioner and decided to go with the passive solution.

    With a passive solution it's much easier to connect 4 belts instead of 2 and my rig will stay less complex because there's no need to add an extra servo + driver. No need for a second controller or extra connections ( on a mobile rig )

    With a passive 4 belts seat tensioner, there's also no need for an uncomfortable crotch strap, to avoid the belt being pulled upwards ( like in the rear seat belt tensioner version )

    [​IMG]


    I designed and 3D printed a new "sticky foot" for the SFX100. Into the foot there are 2 M6 threads for the eye bolts. Connecting the belts to the feet in stead of the ground, makes it still possible to put the entire rig on a cart to move it, without additional effort.


    No springs, springs are for pussies :D

    [​IMG]


    The belts are mounted parallel to already fixed seat belt mounts on my GS-5. I have done this for a couple of reasons

    1. When playing a game that can use a lot of heave or Pitch (like Dirt Rally) you really don't to want have a passive seat belt tensioner pulling you in the seat at every bump
    2. When friends come to race and have a different seating position than me, you still want them to be able to be strapped into the GS-5.

    In both cases i easily unhook the 4 belts and stil have the fixed seat belt like i always had.

    [​IMG]

    The back belts are also being pulled, but still need some additional work. I still need to add some guides and rolls on bearings for maximum effect.


    [​IMG]


    Pros & Cons of the Passive Seat belt tensionser 2.0


    Pros:
    - It's the best 20 bucks i ever spend on my rig
    - Braking becomes super immersive
    - I now have that instant, on the brake feeling with pressure coming from the front
    - Like the GS-5, these are forces directly to the body and really give an extra dimension
    - Simple, no additional servo or second controller needed
    - Easy tunable through the surge travel in Simfeedback
    - Small heave movements are not felt thought the belts
    - You can even add some slack to the tension belts, so you only feel the tension during large surge movements
    - Very easy to disconnect and still use the normal fixed seat belts for rally games, friends ect ect.
    - Does not affect sliding my seat back and front (for getting in or out of the rig) in any way


    Cons
    -Large rig movement like heave, roll, pitch and sway will be felt through the belts to
    -With pitch enabled, going uphill results in less tensioning, braking while going down hill results in more tensioning
    - DO NOT enter the rig with a full bladder :roflmao:
    - Like all passive seatbelt tensioners they are seat position based. If you move the seat, you have to re-adjust all the belts.
    - Potentional dangerous if you do not know what profile you are using or have a clear understanding that both surge and pitch travel will added op top of each other in simfeedback under certain circumstances



    Conclusion and STL link for the "passive sticky foot"

    I really happy with my passive seat belt tensioner. It still needs some work, but i like it so much that for now i decided not to go for active seat belt tensioner anymore. Simfeedback profiles still need to be adjusted and perhaps even my GS-5 profiles might need some tweaking.

    The build was cheap and pretty straight forward and also did not impact the looks my rig in any major way. To have this extra effect on a mobile rig, without adding any substantial "setting up time" is just great.

    If you want to give this a try, I have uploaded the stick foot passive to my github which you can find here:
    https://github.com/HoiHman/Simfeeback-STL-feet


    For guys who have read the entire opening post and still are wondering "what are the rubber bands for"

    They are there to keep the rubber feet from falling of when the rig is on the cart to move it.:)

    [​IMG]
     
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  2. EsxPaul

    EsxPaul
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    Awesome work mate :thumbsup:

    I'll be referring back to this thread when it's my time to try this out. I'm glad you explained the elastic bands. It was bugging me all the way through the post and I wouldn't have slept tonight unless I had the answer:roflmao:
     
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  3. Black_rat

    Black_rat
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    Very interesting, will be following this as its the next step for me, then saving 3k for the GS5 lol
     
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  4. Mascot

    Mascot
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    Nice work Henk! With my original version I had the belts attached to modified foot pods similar to yours, but only the shoulder webbing, not the lap straps. I had rigging screws for adjusting tension (which is necessary if you're wearing different clothes - it's surprising the difference between a teeshirt and a fleece) but these were a bit fiddly, hence why I later changed to a drawbar spring which auto-adjusts tension. I found that by crossing the belts (as in the image below) I'd feel cornering forces individually on each side as the rig rolled left and right. It was a pretty good additional effect. My lap straps have only ever been fixed to the chassis but I did think about connecting them to the feet as well. I think I was put off the idea as there'd be a lot of rubbing of webbing against seat bolsters, and I didn't really feel like I needed lap tension anyway, I wanted to feel accelerating/braking surge mainly in the shoulders/chest.

    20190316_233339.jpg 20190316_233920.jpg 20190317_100659.jpg

    This all worked really well but I'm much happier with the new drawbar spring/shared board version. The shared board definitely stops my rig from walking too.
     
  5. o Tiger Feet o

    o Tiger Feet o
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    Is that a 'metal layer' on top of the printed foot. (where the bolts screw in?)

    Im guessing thats not something you can buy off the shelf?
     
  6. wajdi

    wajdi
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    Where can I order these springs?
     
  7. Mascot

    Mascot
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    Check the SFX-100 thread, details were reposted in the last week or so.
    :)
     
  8. HoiHman

    HoiHman
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    @o Tiger Feet o It a cnc cut plate, to extra reïnforce the 3D printed part. Probably not needed, but i have CNC router, so this was very easy and quick to do. The thread is in the 3D printed part and i have made the foot 2 mm thicker to give it extra strenght.

    @Mascot
    Your solution is great to, but did not work for my mobile rig. I like your idea of crossing the belts, but i have disabled sway on the SFX100 and let the GS-5 do the G-forces. It does it so much better :cool:

    About the lap belts, i would absolutely recommend you give this a try. There's nothing like being pulled into the seat by 4 belts at the same time in sync. Find a solution for them rubbing against the seat, you will be rewarded for your efforts. Now you know you at least need to give this a try.

    Ik know that the difference is clothing can be massive in the feeling you experience in "the belts"
    It always has been like that for me with the GS-4/GS-5.

    Did some updates on the rear seatbelt today

    I have added a bracket with a couple of rollers. These rollers ensure that the feeling of the pull is a backwards direction and not a downwards direction. They also ensure a smooth transition from vertical to horizontal forces

    [​IMG]

    The positive effect of the high placed rolls is felt directly. I'm still looking into the possibility that higher placement of the tension belts might improve the tension effect even further.




    I was kind of worried that the seat belt will damage the cover of my GS-5 in time, so i have 3D printed a protector and mounted it in the GS-5 cover. You can also see that the rolls raise the seat belt.

    [​IMG]

    The rolls are mounted on a couple of bearings.

    [​IMG]



    Adjusting the belt to my personal liking is a PITA, so i'm happy when friends come over the race, i only have to disconnect the tensionbelts and let them just race without the tensioner, but with fixed seatbelts, which you absolutely need for the GS-5.
     
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  9. BluePotato00

    BluePotato00

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    Thanks for sharing your experience, Henk! I posted in the SFX-100 thread that I recently mounted foot cups into some plywood because I was frustrated having to constantly recenter my "walking" rig.
    I figured since I was already that far that I could easily do the passive belt tensioner. I originally tried bungee cords, but those absorbed WAY too much of the tension so I could barely feel it.

    I don't have a true racing seat with slots for the racing harness, so I fashioned a piece of PVC behind my headrest. It pulls from above instead of down (the problem you mentioned in your first post here), so that is probably good. But the shoulder belts are a bit too far apart so I'll figure out something to do there. And yep, that's my sheepskin seat cover. Only seen one other rig with that feature!

    [​IMG]

    I now have no springs or bungees between the belt and my plywood mounting point and I like that better, but I still wish I felt the effect stronger. Should I just increase the intensity of the "pitch" setting? Or drag those handles in SimFeedback to their maximum diagonal values so the rig pitches more on braking?

    [​IMG]
     
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  10. HoiHman

    HoiHman
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    @BluePotato00 you should increase the max travel of the surge effect, not the pitch effect you have posted above. Drag the dots up to 35-40, but be careful since there's no saveguard if the movement is too big.

    Intensity changes the output value coming from the game. You should take a test drive with real time data enabled and see what the max value is reached under braking. The dot in the graph should be placed on that value horizontally.
     
    Last edited: Jun 4, 2019
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  11. HoiHman

    HoiHman
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    Did some further testing and adjusting yesterday and tonight

    -It took quite some time to find the sweet spot of comfort and maximum immersion.
    -To get maximum effect you need to really be strapped tight into the seat
    -When the seat belts are adjusted right, the difference between 30 and 40 surge is the difference between a comfortable and intense profile
    -The difference between 4 and 2 belts being pulled is about 70-80% in force being felt. This is probably caused when the upper belts only are pulled the bottom belts move up.
    - For me personally, the sweat spot of the center buckle is right on the belly button. I have made the upper belts shorter and the lower belts longer to get it right at that point.
    I had the lower belts lower first, but now my bladder hurts from being exposed to too much force.:redface:
    So until i recover from that, i will leave the lower 2 belts un-tensioned for now.
    - If the center buckle is a the middle of your belly the lower belts are already facing upwards and when you hit the brake you will be pulled back by all four belts in sync. Result in a strong and really present force. At 40 surge, it the strongest force felt in the rig, stronger than the SFX100 movements or the GS-5 panels.
    -With the seat-belts tightened really good i have discovered a surprised new side effect which is really awesome. The engine RPM from my BK advance at the back of the seat is being transferred through the seat belts to the front of my chest. This means feel the RPM effect on both the front and back of my body.
    Just tested this tonight with Formula 90 V12 in raceroom and it's amazing
     
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  12. wajdi

    wajdi
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    Is it safe to use the passive tensioner without springs?
    I personally use 4 strong springs and Im good with them. I will try your solution to fix the 3th and fourth point but with springs.
     
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  13. HoiHman

    HoiHman
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    Make sure you have the max movement limited and only than it's safe. Without springs you can't just jump in any untested profile.

    I might look into adding some really heavy springs, but only if they don't absorb the initial force and can act as safeguard only.
     
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