DIY Seatbelt tensioner with simtools

HoiHman · Jan 16, 2019

A lot guys that have build the SFX100 are thinking about adding a seat belt tensioner to their rig.

Even though i would have prefered to use one the SFX100 servos doing the work, i have decided to order the parts servo seatbelt tensioner and will start building as soon as the parts arrive.

Parts needed:
Servos
https://hobbyking.com/de_de/turnigy...-servo-33kg-0-21sec-154g.html?___store=de_de1

Turnigy 5A (8-40v) SBEC für Lipo :
https://hobbyking.com/de_de/turnigy-5a-8-40v-sbec-for-lipo.html

Aduino uno
https://nl.aliexpress.com/premium/a...SB_20190116083039&origin=y&catId=0&isViewCP=y

Power supply:
Still need to order one, or if the specs of the servos allow it, i will use the 6v power supply of my GS-4

I will be copying the build from @Ringorian and @saxxon66 who have already a topic with complete instruction on the german forum.

https://forum.virtualracing.org/sho...ffer-100-Euro-(auch-Ohne-Motion-realisierbar)

Jochen en Micha, feel free to jump in and educate us

metalnwood · Mar 5, 2019

@anton_Chez Sorry, I dont remember what you have for a rig, 8020 or other?

I bought 2M of 4040 from a local supplier at $20nzd/M and a couple of connectors to go on the end that allow me to change the angle. I will need to create a small support as I dont think they will be strong enough to keep their position but they will allow me to the get angle right easily. I have a bunch of CF 50mm tubing and will just put some bearings in the end and mount up top, really it could just be some threaded roun across the top with pvc pipe over for the harness to run on top and would work just as well.

anton_Chez · Mar 6, 2019

Yeah 80 20, GT1 Simlab chassis. Similar to P1 just a smaller main rail (80mm) and slightly different pedal deck.

Where would you connect the anchors to there? Would you run the straps over the tube and then down connected to the main rail? I guess that at least gives you some sort of horizontal harness position. I'm not sure I could be bothered to do all of that especially until I know how the active tensioner will actually mount. I guess for you, you have already felt how it is the other way which is why you're so anxious to get back to that. For me, I have no clue. I'd have to try it with a makeshift design just to see what the difference is. I got a heap of timber off cuts from the downstairs build so I might be able to pin something together quickly.

metalnwood · Mar 6, 2019

How I have it, it would still mount on to the floor but the roller would now stop the pressure coming back down on the top of my shoulders. for active, it would then mount on the rig, probably at the base of this contraption

HoiHman · Mar 6, 2019

That idea really makes sense @metalnwood

For me personally with a mobile rig, it will be probably too much effort setting it all up and removing it again.

Ideally you should mount the fixing points with a passive seat belt tensioner almost at the same height as the rollers. This will ensure that you will get tensioning during heave, still enough during surge.

Either way, passive has to much compromises for me. Too much work setting up, but also driving uphill in (FE Dirt Rally 2) will give me loose belts and driving down hill will tighten them too much.

We need the second controller support.

I'm going to start soon on "fase2" of my rig and will make the preparations so that an active seat belt tensioner can be implemented easy.

anton_Chez · Mar 6, 2019

I'm going to see how hard it would be to knock up a temp solution and see if it's worth pursuing. I feel there is a better way to have these mounted, just don't know how to make it look nice and still have it effective.

Stevie_007 · Mar 6, 2019

HoiHman said:
That idea really makes sense @metalnwood

For me personally with a mobile rig, it will be probably too much effort setting it all up and removing it again.

Ideally you should mount the fixing points with a passive seat belt tensioner almost at the same height as the rollers. This will ensure that you will get tensioning during heave, still enough during surge.

Either way, passive has to much compromises for me. Too much work setting up, but also driving uphill in (FE Dirt Rally 2) will give me loose belts and driving down hill will tighten them too much.

We need the second controller support.

I'm going to start soon on "fase2" of my rig and will make the preparations so that an active seat belt tensioner can be implemented easy.

Henk, on the back of your gs-4 is that a roller you have bolted on, is it fixed or does it have bearings, i need some way of forcing the belt outwards as it comes out of the seat

i tried steveD`s method but the alu plate i had just kept pull the end up so that the profile was just being pulled into the seat,

HugoB · Mar 6, 2019

SeatTime told me that it doesn’t matter if you have the harness going straight backwards or down, the deciding angle is the final one going into the seat, so if you want to have a more upwards pull, you can mount rollers up on top of your harness slots, this will raise the final incoming angle, even if the active tensioner is mounted below to the seat, if the harness enters from a raised roller, its the same as if it enters from behind. Only mounting your harness to the roof, or higher than your seat would give you even more upwards pulling force.

SeatTime’s design uses rollers with mounting slots that fit onto the seat harness entry holes. You can adjust the height of the entry by mounting the rollers higher. The limitation is of course the positioning of the holes, if you have a long back and the holes are below your shoulders, the harness will always be pulling down... but maybe you can make new holes and mount the rollers on new edge to guide the active harness?

HoiHman · Mar 6, 2019

sdubbin said:
Henk, on the back of your gs-4 is that a roller you have bolted on, is it fixed or does it have bearings, i need some way of forcing the belt outwards as it comes out of the seat

i tried steveD`s method but the alu plate i had just kept pull the end up so that the profile was just being pulled into the seat,

The roller has bearings.

anton_Chez · Mar 6, 2019

So basically me getting his active tensioner means I don't have to do anything if I want a different angle for the shoulder harness??

metalnwood · Mar 8, 2019

OK, this was my project today, to get the seatbelt higher behind me and not pulling right down my my shoulders.

I was going to use some 50mm diameter CF tube I had, which would have required me to make some ends on the lathe to insert the bearings.. Then I found some offcuts of this which is 25mm outside and 22mm inside.. exactly the same diameter as these handy bearings I have.. So I epoxied a couple in and done.. It is all adjustable, the tube just some m8 threaded rod going through it and each end goes in to a tnut and tightened with a m8 bolt. So I can loosed a couple bolts and move it up or down before securing it in place.. Happy it is done.. getting to the point I want to stop playing with the rig and playing with the sims

If I go with an active tensioner this will also be perfect for that and I can put a motor mounted to it down the bottom.

Having just spent a grand of my local $$ on that seat I was not about to start drilling in to it to do this another way!!

anton_Chez · Mar 8, 2019

So how's the feel now that all of that is done? Do you reckon you need the round bit for the belt to sit on? Or would a 40mm profile still be fine? It's not really moving that much especially if it's anchored back down onto the moving chassis itself. I'm tempted to try this. I've just added some shoulder pads to the harness and I think it makes the problem worse. Maybe squaring off the entry of the shoulder belt into the seat might help it.

HugoB · Mar 18, 2019

anton_Chez said:
So basically me getting his active tensioner means I don't have to do anything if I want a different angle for the shoulder harness??

Not really, but his design supplies some very neat CF rollers with mounting brackets that can be attached to standard seat harness guiding holes, you can then mount these rollers higher to get a more upward pulling effect. You'd have to make a raising plate from the edge with some wood or aluminum maybe? You could maybe attach the rollers to the top back side of the seat to get them high enough, slightly away from the seat so the belt rolls over from behind/below, then down into the holes of your seat.

To get the harness pulling upward from your shoulders instead of down on your shoulders, your holes of course need to be higher than your shoulders.

anton_Chez · Mar 18, 2019

Yeah fair enough. I've been put on hold anyway for now and probably will get to a stage where I just lose interest in it. He isn't taking any more orders for now.

Looking forward to your impressions. I've got the passive system working not too bad now. Still needs tweaking.

White Hawk · Sep 9, 2019

So, is there a active system you can buy for a static rig?

nerdthewise · Apr 4, 2020

SimXperience is realeasing one in the nearish term.

RCHeliguy · Apr 4, 2020

White Hawk said:
So, is there a active system you can buy for a static rig?

There are multiple solutions available in DIY form for static rigs and rigs with seat movers.

Of course for motion systems with surge there are passive mounts with spring action for tensioning.

cyberct · Jul 14, 2020

RCHeliguy, do you have experience with any of these active systems for static rigs?

I'd go a DIY route but I want something that works "good enough" for VR immersion with directions that are simple enough to follow without being a rocket scientist.

I finished my wind sim setup following this guide (and adding comments / corrections to it in the comments) and love it so I have the itch to keep adding little bits of immersion in my passive, less expensive rig.