DIY kits for true force sensitive brake pedal selling!

[Niels Heusinkveld]

Hi guys,

Some of you probably browse though the RSC forums but I'd just like to point you to something that is the result of a lot of research and techy stuff by the community and yours humble truly: parts to make a force sensitive brake pedal.

No longer do our brake pedals have to respond to motion, now we can feel the force! Just like real cars work. Anyone who tried my pedals using this force sensor is amazed. It really puts even the most expensive commercial pedal set in the corner for pure realism of operation! And rated at 50kg you could of course use a wimpy 5kg, but hardcore users will use all the 50kg and find out that driving a race car is hard work! :)

With LFS I always found braking the toughest thing to do. I am much more steady now, as you don't easily 'overshoot' using force. Weaker motion based pedals are easily pressed too far.

Perhaps the coolest thing is driving the single seaters and the feeling of simply loosening the 'tension' in the leg to slowly get off the brakes as downforce levels drop. No movement in the pedal, just pressing it less hard. :thumb:

Point your browsers at:
http://forum.rscnet.org/showthread.php?t=239373

Regards,
Niels Heusinkveld

[XCNuse]

..i still dont get what everyone 'feels' through brake pedals, when i drive.. they feel the same no matter what.. well.. i mean, once you press down it stays there and doesnt fling back.. but i mean .. what do you even 'feel' through pedals?

[tristancliffe]

Nuse: Well, it's not pedal feedback as such, but car brakes are controlled via pressure applied, not distance pressed. Most commercial brake pedals are the distance type, and hence feel wrong.

[Rtsbasic]

I like the sound of it..and the price isn't too overkill..but would it work with the standard DFP pedals, or only fancy sets that cost big ££ ?

[B2B@300]

Also our brains are able to make more precise adjustments with applied pressure rather than positioning the travel type brake pedals i.e. much easier to be more consistent on each lap... what would be really awsome though is ffb through the brake pedal :D but have to wait awhile for that one I guess...

[mrodgers]

Niels, I was wondering if you were the same Niels over there when I saw a post earlier here from you. I've been reading that thread over at RSC, really cool stuff. I also DL'ed the pics and video (I think video) you posted about your pedals. I loved the construction, simple and very adjustable, if I remember correctly. I hope you don't mind me copying the idea of them, except I probably wouldn't do the weigh cell thing. I'm all about using scrap from the scrap bin at work and going the ultra cheap as I can route. Would only cost me a couple of pots and USB connector that way.

Your's are the ones mounted so you have allthread adjustment for pedal height and a bottom stop if I recall.

[axus]

Really nice piece of work... how difficult would it be to have a motor in there thtat would provide force feedback? Surely you can link it up to LFS with OutSim - if not through anything else (not sure if OutSim gives wheel speed so you can compare it to car speed), then through acceleration. If you lock your wheels and acceleration drops then the pedal puts a force against your foot... or do you feel that it is already realistic enough?

I'll look through all the parts and see if I can get my hands on them in South Africa and for how much. Thanks for the info!

[B2B@300]

Really nice piece of work... how difficult would it be to have a motor in there thtat would provide force feedback? Surely you can link it up to LFS with OutSim - if not through anything else (not sure if OutSim gives wheel speed so you can compare it to car speed), then through acceleration. If you lock your wheels and acceleration drops then the pedal puts a force against your foot... or do you feel that it is already realistic enough?

I'll look through all the parts and see if I can get my hands on them in South Africa and for how much. Thanks for the info!

Outsim doesn't give enough info at the moment... but may in the future :scratchch maybe we should just make one then request support for it :D then lfs would be at the forfront in that area also :smileypul

[Niels Heusinkveld]

The kit is just the sensor (a piece of ~ 13x3x3cm aluminium).. You have to create the actual pedal around it. I don't think there are easy ways to modify Logitech or any commercial set for this, but you can see pictures of my pedal set linked to at RSC which is I think as simple a design as possible if you want a functional and adjustable set.

And if I get 100 people who want such a pedal set I might consider it :)

Oh and I don't think force feedback would do anything for a brake pedal. If your brake discs are nice and round you don't really get any feedback from the brake pedal. Only when something is seriously wrong does the total feel of the pedal change. If the sim (like GTR) models brake temperature you will find that you have to press less hard once the brakes are at their optimal temperature and you have to press harder when they are not..

[KTy]

I first read "for true force feeback sensitive brake pedal"... That would have been *really* interesting !

Good stuff anyway :)

[Niels Heusinkveld]

I'm most curious why people think a brake pedal needs feedback? I'm not the braking feel expert having only driven road cars but I simply can't imagine there IS any feedback in a real pedal under normal use!

Excessive wear / bioling fluid might make the pedal more spungy but under normal conditions I really can't see why? What am I missing? :)

[tristancliffe]

You aren't missing anything - there is no feedback in a pedal.

When people say a pedal has feel, it means that a linear increase in pedal force gives a linear increase in braking force. If you lock a wheel, or threshold brake, or touch the brakes gently, there is not 'feel' through the pedal. It's all about a feedback system between how hard you are pressing and how quickly you are stopping. Therefore, you don't need a 'feedback' system in the pedals, just pressure sensitive.

Thats why I have ordered ECCI with PMBII (pressure sensitive apparently).

Oh, and some ABS systems shake the brake pedal to let you know it's working, but as no real racing car should ever have ABS, we don't need that.

[Scawen]

I agree, there shouldn't be feedback in normal operation, except when the ABS comes on.

A fault like a warped disk would make it wobble with each rotation. And air / gas / etc in the system would make it more spongy.

Tristan, are you sure about no racing cars having ABS? I know it's like that in several classes, such as F1, and as a guess that would apply to most single seater classes. But i guess some (or most) touring car classes allow ABS? There's no reason to want to lock a wheel so i guess if it's allowed then it will be used - as it has one advantage over purely driver controlled systems, because it can do its momentary release operation on individual wheels.

[tristancliffe]

As far as I know, most major race series don't allow ABS. I think it is allowed in basic production car classes if the car has it as standard. Of course, I could be wrong, and I'm sure if I am someone will take pleasure in telling me which series of any note DO allow ABS.

[the_angry_angel]

Awesome idea Neils. Very cool :up: I'm really tempted to order some, but I know the gf wouldnt like that very much :(

Of course, I could be wrongBackpedal, backpedal, backpedal ;)

[Niels Heusinkveld]

Tristan, although I think the ECCI pedals are a good product, their brake pedal is not force sensitive. They use a slightly progressive system but applied force isn't linear with actual braking as far as I know.

Their USB connection also doesn't allow axis swapping or inverting which might cause some issues with certain games where the Y axis in particular might only work 50%.

I am of course biased as I made my own which absolutely rock, at much less than half the price of a set of ECCI's or BRD's.. :)

N

[tristancliffe]

Tristan, although I think the ECCI pedals are a good product, their brake pedal is not force sensitive. They use a slightly progressive system but applied force isn't linear with actual braking as far as I know.

Their USB connection also doesn't allow axis swapping or inverting which might cause some issues with certain games where the Y axis in particular might only work 50%.

I am of course biased as I made my own which absolutely rock, at much less than half the price of a set of ECCI's or BRD's.. :)

N
Gulp! We'll see. If not, I can invalidate the warranty by mixing your load cell and the ECCI stuff :D As for axis invertion, most serious race sims off the ability to invert and choose axis as required, as well as sensitivity adjustments. I'll keep you posted on the pressure sensitive ECCI thing though when they arrive.

Indeedy - apparent the PMB is Progressive Modulated Braking. The pedal gets much harder the further you press it. It's not clear from their websites or reviews I've found if the pressure or the distance is measured. At the end of the day, it's not necessarily how you measure it, it's the final outcome. (this is me justifying the expense of ECCI when a better option might have presented itself).

[DodgeRacer]

I agree, there shouldn't be feedback in normal operation, except when the ABS comes on.

A fault like a warped disk would make it wobble with each rotation. And air / gas / etc in the system would make it more spongy.

Tristan, are you sure about no racing cars having ABS? I know it's like that in several classes, such as F1, and as a guess that would apply to most single seater classes. But i guess some (or most) touring car classes allow ABS? There's no reason to want to lock a wheel so i guess if it's allowed then it will be used - as it has one advantage over purely driver controlled systems, because it can do its momentary release operation on individual wheels.

There is some feedback through the pedal when autocrossing my car, from heating them the rears warped a little during one run, but other than that nothing, as far as ABS goes i remember a certain series i came across that allowed it, and i know F1 allowed it many years ago, but as with the feedback, nothing substancial.


Clutch is a little differnt, i can feel the force through the pedal as to how much the clutch is grabing, slipping, but its also distance oriented.

[Niels Heusinkveld]

I don't think you will be dissapointed Tristan, they seem very solid and adjustable, have decent electronics, and are the closest to 'force sensitive' you seem to be able to buy on the sim markets. :)

[DodgeRacer]

Now if someone would just get to work on a correctly force modeled non gated shifter we'd be in heaven :D

[lowgoods]

Indeedy - apparent the PMB is Progressive Modulated Braking. The pedal gets much harder the further you press it. It's not clear from their websites or reviews I've found if the pressure or the distance is measured. At the end of the day, it's not necessarily how you measure it, it's the final outcome. (this is me justifying the expense of ECCI when a better option might have presented itself).

I'm happy to own a set of those ECCI pedals. Indeed, they do not have a force sensor but a second spring, that is compressed in a non-linear way in correlation to the pedal range. Anyway, it feels very very good! Of course I haven't tried out a system yet that is using a force sensor as proposed in this thread, so might be that this feels even better...

[Sapient]

As far as I know, most major race series don't allow ABS. I think it is allowed in basic production car classes if the car has it as standard. Of course, I could be wrong, and I'm sure if I am someone will take pleasure in telling me which series of any note DO allow ABS.
Someone had to do it:D

Porsche SuperCup both here in Oz and Internationally run ABS.
Secondly I would have to disagree about the amount of feel you get from a brake pedal, by regulating the amount of pressure applied and therefore the amount of pressure on the pedal you can almost feel a brake lockup impending, and secondly, as someone else mentioned, brake performance tends to degrade over time or with over zealous use.....particularly, in say endurance races, when you push hard early. The pedal actually needs to be pushed further to get the same braking result.

For me, one of the hardest issues driving a simulator as opposed to a real race car was pedal feel, in fact most times I wear only socks so I have a better idea of what position the pedal is in. I guess I could pull out the old race boots to add that sense of realism if I wanted:)

[B2B@300]

You can feel lockup through the pedal... it is very easy to feel with abs (but what you feel with abs is different because you feeling hydraulic pressure being released then reapplied) but you can feel it in normal hydraulic systems too :shrug: especially on gravel roads :) think about it a hydraulic brake system is a "semi-solid" system it transfers your foot force from one point to another with amplification, so it's only natural that the reverse would be happening but with negative gain (instead of positive)... point is there is feel there, but i guess it depends on the hydraulic system design (amount of gain), the shoes you are wearing and your driving style :D Same is true for the old rack and pinoin steering without power assist, you can feel the road more without powerassist but you can still feel it with power steering but just to a much lesser degree :tilt: If you replaced the hydraulic brake system with a pure mechanical system you would feel alot I'm sure... so the same is still there but just to a much lesser degree :) also the feel you get through the pedal is not just from the hydrolic system, there's also vibrations etc tranfered from the chasis, guess what i'm saying is when your driving you get a hell of alot of feedback through your feet and seat of your pants :D

[Theafro]

the 'feel' for me is kinda like a slight vibration,:shrug: the pad touching a really hard and 'bumpy'-ish disc, but fed to me via a fluid with lots of inertia, when the wheel locks you feel the absence of this and a very slight depression of the pedal.:scratchch

it depends on you're brake system tho', get rid of any ABS, chuck away the vacuum servo, throw out the rubber hoses for nice shiny braided ones:D and go through the whole mechanism of the pedal, cylinders, pipes, and calipers/wheel cylinders. get rid of any slack movement you find:smileypul but make sure the brake pedal has a light return spring on it to ensure 'pumpability':tilt: and to stop the brakes binding on:D

[RMachucaA]

well, i felt a wicked pulse when i was trying to slow down from 200 km\h in my 93 nissan sentra, i overheated the brakes badly and warped the disc....even though i was feathering the brakes, letting them cool for a moment... i guess im faster then my old car could handle :P.

Also, you can feel the difference in pressure when the wheels block.

[AVV1]

Hi.
I have one of these load cell kits that I bought from Niels a few years back but never got to install them. Does anyone know what is the voltage for the amplifier input/output? is it compatible with the Logitech g25/27, and PS3?
or needs to be connected for example to a Leo Bodnar USB board ?

Thanks

[IKke5165]

I really don't get what it adds over a "normal" steering wheel brake pedal. If your brake pedal has a linear spring (most regular pedals have afaik), you already have a pressure sensitive brake pedal because of Hooke's law which in a nutshell says:

Mathematically, Hooke's law states that
http://upload.wikimedia.org/math/9/0/2/902597b2e025eaa110979760f10189e9.png
where
x is the displacement of the end of the spring from its equilibrium position;
F is the restoring force exerted by the material; and
k is the force constant (or spring constant).

See: http://en.wikipedia.org/wiki/Hooke's_law

[Hallen]

I really don't get what it adds over a "normal" steering wheel brake pedal. If your brake pedal has a linear spring (most regular pedals have afaik), you already have a pressure sensitive brake pedal because of Hooke's law which in a nutshell says:



See: http://en.wikipedia.org/wiki/Hooke's_law (http://en.wikipedia.org/wiki/Hooke%27s_law)

A properly setup, properly bled brake system should only have about 2-4cm of travel. After that, it's all in how hard you press. The pedal won't move any more from there.

The first bit of travel provides very minimal braking force. The real force gets applied once you hit the point where the pedal isn't moving anymore.

A spring system must use pedal travel to gauge how much braking to apply. It may get harder to go further down on the pedal, but it's still the movement of the pedal that indicates how much braking to do. That's not how a real hydraulic brake system works.

[logitekg25]

still up for grabs? is it expensive?

[IKke5165]

@Hallen:

If you would use a force sensor only, your pedal will hardly move. and if you use a spring on top of the sensor, you still get the same thing as with a normal spring (providing it is linear). Unfortunatly the link in the initial post doesn't work anymore but that is how I remembered it to work. :shrug:

[tristancliffe]

The force sensor plus spring gives the springy initial feel (as the spring compresses), but once coil bound the pedal won't move yet you can still increasing the braking input. In a real car you have the 'soft' initial part when you're moving fluid and the pads, and the rock hard second stage where nothing is moving (well, not much) but your pressing the pads harder against the disc.

Purely movement based pedals (most commercial pedals) are very unrealistic.

[IKke5165]

Thanks that explains alot :)

[AVV1]

So, anyone have used this particular kit? that can tell me if the specifications of the electronics on it, is compatible with G25 and PS3? or it has to be used in combination with a USB board like Bodnars.

I tried to contact Niels but got no reply yet.

Thanks

[Hallen]

@Hallen:

If you would use a force sensor only, your pedal will hardly move. and if you use a spring on top of the sensor, you still get the same thing as with a normal spring (providing it is linear). Unfortunatly the link in the initial post doesn't work anymore but that is how I remembered it to work. :shrug:

I was referring to a spring attached to the pedal in some way to give a bit of resistance. The real sensor is of course the potentiometer that is attached to the pedal and reads how far it has traveled. Pedal travel becomes the measure of how much braking is happening on a commercial brake pedal set used for simulators.

The system here uses something that looks like a metal bar and it measures pressure, not motion. So yeah, you would need some kind of free travel, probably with spring resistance, and then contact with the pressure bar.

A truly accurate system would have some way of moving that pressure bar "back" so that if your brakes get hot or worn out (like in a 24h race), the "soft" part of the pedal throw would get longer and longer. It would take some kind of output from the game in order to do that. This, in my mind, would be the ultimate brake simulator setup.

[sosna]

If anyone is interested you chould check this out http://www.apelectrix.com/.Its really easy to install and totally transforms the brake feeling,its based on pressure and not travel.Especially for iR users,braking will be much more easier.

About it in iR forum http://members.iracing.com/iforum/thread.jspa?threadID=28939&tstart=175

[elnino_effect]

Hi.
I have one of these load cell kits that I bought from Niels a few years back but never got to install them. Does anyone know what is the voltage for the amplifier input/output? is it compatible with the Logitech g25/27, and PS3?
or needs to be connected for example to a Leo Bodnar USB board ?

Thanks
Woot, first post....

A load cell generally outputs about 2mv per volt of 'excitation'. Ie, if you run the load cell at 5v, you will get a maximum output of 10mv. Leo sells either the USB interface with 7 analogue inputs etc and includes a load cell input OR, you can buy one of his load cell amplifiers (http://www.leobodnar.com/products/LC-amp/) to retrofit a load cell to replace a pot running @ 5v.

I am going to make my own LC amp but i am very electronically minded. At only about AUD $4 for the main IC on the board and only a couple of resistors and a capacitor, it's not too hard. The other reason is that my joystick interface uses 3.3v and not 5v. Then again, my load cell is 100kg so i'd probably not get it past 3.3v output anyway :)

[KOB_CHEESE]

If anyone is interested you chould check this out http://www.apelectrix.com/.Its really easy to install and totally transforms the brake feeling,its based on pressure and not travel.Especially for iR users,braking will be much more easier.

About it in iR forum http://members.iracing.com/iforum/thread.jspa?threadID=28939&tstart=175

Has anybody here used this brake pedal mod (in lfs/rfactor) - it looks like a good solution ?

Cheers,

Rob :smileypul