Sim Brake Thoughts

[Jet Badger]

I have seen the Bic pen one on simhq Probably the main reason why I didn't make one like that was that I wanted to create one myself. It's inferior but meh, it's mine

 

[mrbasher]

I have seen the Bic pen one on simhq Probably the main reason why I didn't make one like that was that I wanted to create one myself. It's inferior but meh, it's mine

I think what you have there should be on par... Even if it's not, it's a good learning experience Just make sure your magnet is close enough to the sensor.

You might think about experimenting with different magnet shapes too. That application note sheet that I posted above breaks down the different types quite well. Even though that sensor may be a switch, the info in the document is more generalized.

 

[derekspeare]

Allegro 1302 hall sensor. Use a Neodymium N40+ mag.

 

[kikie]

That is certainly an option... I'd suggest the following setup:

5 volt cell phone charger and 3.3 volt low dropout voltage regulator. Then power the load cell via the 5 volts coming from the phone charger and power the load cell amp via the output of the 3.3 volt regulator. This will ensure that the output of the load cell amp does not exceed the 3.3v expected by the T500.

Pffff

I definitely have to stop reading this thread. It's getting frustrating.



I understand what you mean. Now I just need to figure out how to connect everything. Is this the same principle when using a pressure transducer? I prefer a tranducer over a LC.

For a 3.3v regulator, I would suggest this MCP1700-3302E/TO (look up the part on digikey or something) You also need a cap with it or it won't work right. Reading the datasheet is a good idea They have example circuits in there.

cap?

 

[mrbasher]

Pffff

I definitely have to stop reading this thread. It's getting frustrating.



I understand what you mean. Now I just need to figure out how to connect everything. Is this the same principle when using a pressure transducer? I prefer a tranducer over a LC.

cap?

I'd worry about the mechanical bits before you worry about the electrical bits. That's just my gut feeling.

Once you know what mechanical pieces you are going to use, then we can get going with the electronics. The are not a big deal and I can provide you with exactly what you need when you get there. However, I am going to suggest that since it will diverge from the subject at hand quite a bit, we should do it via PM. If you'd like to post about it when done or the progress, then it might be best to start a new topic on that.

P.S. a "cap" is a capacitor

 

[kikie]

Ok, thanks!

 

[kikie]

Double post.


I'm going to have to take a brake from the whole Sim Brake thing. I get an average of 4 to 5 hours sleep. I'm not sure that it is because of the entire should - I buy - a - new - wheel or not and what - should - I - do with the brake pedal. Maybe there is something else going on. It's 5:34 am right now.

mrbasher, you probably won't be hearing from me in the next couple of weeks, maybe even 2 or more months. If I buy a new wheel and I'm probably going to make a(n) hydraulic brake with pressure transducer and than I'll contact you again mrbasher. This is less complicated than a pot based brake with a perfect construction to make the pot as good as an hydraulic system.

Or maybe I'm going to consider Derek's new pedal. 2 conditions:

1) price
2) being able to connect the wheels into an existing wheel.


Good night, going back to bed.

 

[Jet Badger]

I think what you have there should be on par... Even if it's not, it's a good learning experience Just make sure your magnet is close enough to the sensor.

You might think about experimenting with different magnet shapes too. That application note sheet that I posted above breaks down the different types quite well. Even though that sensor may be a switch, the info in the document is more generalized.

Well, you're right about learning experience

I have replaced that hall thing with a linear hall sensor from a CD-ROM (one of those uber tiny SMD ones, what a bitch to solder). Even more so I managed to get it to work, though it showed another issue with my hall sensor contraption - the magnet's poles are not where I'd like them to be... I believe round shaped magnets would fix that issue

 

[mrbasher]

nice work! How small is the sensor? little stuff like that can be "interesting" to solder by hand without a decent iron and solder/flux, and even with. One of the chips on my Logitech to Fanatec shifter adapter is a 10 mssop package which is about 3mm across.

Were you thinking of a round magnet or a ring magnet? I wonder what putting a ring magnet around the sensor would do. Might be cool to try and adjustments would be simple enough.

 

[Jet Badger]

Thanks!, It's the smallest component I've ever soldered successfully, it's about 2x1.5mm. But my trusty $4 30W soldering iron makes miracles even though I suck at soldering

I was thinking about a round magnet, but the idea about using ring magnets is really nice. There's one of those in a cdrom aswell, it's inner diameter is just a tad larger than a normal-sized hall sensor, it's definitely worth giving it a try

 

[mrbasher]

I have to say, I love the ingenuity of your "third hand." It is excellent. Where there's a will, there's a way!

 

[Jet Badger]

Well that was supposed to be a temporary solution... a couple years ago. It was one of those bingo moments when you see a pile of unrelated scrap and think "I can make something useful out of this".

 

[Zathra5_]

A couple more thoughts. When you add viscous/viscoelastic elements things get complicated really quickly. An improperly designed mechanical system could lead to either a load cell or displacement based system to give you strange results. My CSP V2 pedals just arrived yesterday so I'll use them as an example. The new brake system basically involves two mechanical systems in parallel. One consists of the oil damper and spring and the other consists of the PU foam and load cell. In a system with only elastic elements, load would be distributed through the two systems in an easy to predict manner. Thus both distance and force measured by the load cell would be related to how hard the driver pushes. However, if you add a damper to one side things are more complicated. Then the load sharing between the two sides becomes speed dependant. Now if the driver stomps on the pedal as fast as he can, more of the load is supported by the damper. This will shield the load cell from the force the driver is pushing. This is obviously not what we want. I think that Fanatec gets away with this because the damper doesn't offer a lot of resistance. It looks to me that it was designed just to give the pedal a little bit of a dampened feel with low forces and the resistance to the higher forces is mostly provided by the pu foam. So it adds a more realistic feel without compromising the load cell signal. At least I think that's what they were thinking. However if someone was to decide to use a similar system but use a stronger damper, it could be detrimental to brake performance.

 

[kikie]

question about the hall sensor magnets.

Does it have to be N40+.

Which type of magnets is also suited to be used with a hall sensor?


EDIT: I contacted a local electronics shop for the hall sensor and he asked me questions I can't answer.

He wanted to know if this sensor is a 2.5 of een van 1.3mV/G.
If it is a throug hole or a SMD. I believe it is a SMD?


I have decided to start simple.
I'm going to use a Logitech Attack 3 joystick and use the potmeters and PCB boards to make my first DIY pedals. If that works out well, I want to make a descent set of pedals, using a hall sensor or a hydraulic system.

But first things first and start simple.

 

[Jet Badger]

One I can tell you for sure - you want a through hole sensor. Learn from my mistakes and make sure you get linear ones. Can't really comment on magnet choices but I'm sure any strong rare earth/neodymium magnets would do the job, the recommended ones would probably work better but I don't think that the difference would be noticeable.

 

[mrbasher]

question about the hall sensor magnets.

Does it have to be N40+.

Which type of magnets is also suited to be used with a hall sensor?


EDIT: I contacted a local electronics shop for the hall sensor and he asked me questions I can't answer.

He wanted to know if this sensor is a 2.5 of een van 1.3mV/G.
If it is a throug hole or a SMD. I believe it is a SMD?


I have decided to start simple.
I'm going to use a Logitech Attack 3 joystick and use the potmeters and PCB boards to make my first DIY pedals. If that works out well, I want to make a descent set of pedals, using a hall sensor or a hydraulic system.

But first things first and start simple.

Try not to get too wrapped up in the magnet rating. N40 is suggested because it's a nice commonly found magnet rating that is sufficiently strong, even in at small sizes.


"He wanted to know if this sensor is a 2.5 of een van 1.3mV/G."
He's asking if you want it to be 2.5 volts output with no magnet around it. The sensitivity is 1.3mV/G, just say yes, that's normal.

"If it is a throug hole or a SMD. I believe it is a SMD?"

You want through hole, probably will be a SIP package.

Make sure to tell them you want an analog output sensor, not a switch. That is most important.

As for your plan, that is a great idea. It will only work properly on the PC though.

 

[kikie]

Thanks both of you


Managed to assemble something that resembles brake pedal and installed the Attack 3 potmeter.

It's working! Playing Netkar pro, I was able to use this brake pedal...... but it was just a test and the little pot wasn't calibrated well enough. I ended up locking up the front wheels all the time. But it's working (I already said that, didn't I).

It looks like sh?t.

I didn't buy anything, used what I could find and .... it didn't take long to make it.

Don't laugh but here is my master piece. LOL

Leo Bodnar has the Allegro A1302 hall sensor. And you can connect it directly to his BU0836 analog inputs.

Now I need to think about what I want,.... hall sensor or hydraulics. I have no idea how to install the magnets but if I do what that guy did with a Bic penand skate board bearing, I think I can pull it off.

 

[mrbasher]

Based on this, I think you'll be able to handle what you have planned. I know you think it looks bad.. However, you used what you had to make something that actually works. Imagine if you had the pieces you needed... I'm confident you'll get there.

To fix the calibration, open up the gaming device properties in windows and do the calibration there. It will set the min and max pedal travel.

 

[kikie]

Thanks


I did the calibration in windows and in netkar pro but the pot is not perfectly centered. There is not enough travel using this setup. It is from 0% brake until 100% is just a few steps (degrees that the pot turns). It's not enough to have accurate brakes.

I now think I understand what it means to lose resolution though.

 

[mrbasher]

I now think I understand what it means to lose resolution though.

That and you understand why it's happening.

 

[kikie]

That and you understand why it's happening.

yep I think I do. Not enough travel and calibrated in this small window of travel. Not enough signals output from the pot.

Is it worth while to use hall sensors for the throttle and clutch pedal instead of very good and accurate potentiometers?

 

[mrbasher]

It's a bit of a toss up... if you can engineer the mechanics of the pedals such that they use as much of the pot travel as possible, the pot is great. However, hall sensors require their own engineering requirements.

You are right on with your observation of the pot. It's about this simple:

With 5 volts in the pot outputs very near 5 volts turned all the way one direction and very near 0 volts turned all the way the other.

The device reading this signal, generally, breaks up this voltage swing into steps. (the resolution) If your pot only turns half way, you get half the resolution.

The same happens with a hall sensor that is not set up properly.

I know you got it, just reiterating because you said "I think I do" I'm confirming

 

[derekspeare]

Attached is a PDF of hall sensor basics I created a while back. There is an error in the diagram, and that is you must have either the NORTH Faces or the SOUTH Faces pointing TOWARDS each other for things to function like they should.

The trouble with this configuration is that you get a flat spot in the middle when the hall element is equidistant from the mags. This is a condition due to the magnetic lines of flux (a subject I enjoy quite much, actually...as an aside, magnetic lines of flux and aerodynamic boundary layers are identical on paper and are easily seen by functions involving the square root of -1, my personal favorite of numbers, 'i' )

Anyhow, you can use on mag just going to and from the face of the hall sensor, but you get half the resolution - no biggie if you're using a 12bit board.

There are other ways to use the mag/hall setup, but this one is pretty simple to do. Just use STRONG mags for the best results. The pedals I have in development use hall sensors for the T and C

 

[kikie]

Eagerly awaiting the release of Derek's pedals! Or at least some info and initial price.

In the mean time, I'm going to see what it takes to make my own. Building stuff, to play games is more satisfying than playing games.

 

[kikie]

Just got an interesting email.

I can get the G25 for €70 ($92). Apparently in good working order. Only the AC adapter is missing.
The G25 pedals could be a good pedal set to start working on a hydraulic or hall sensor based brake system.


EDIT: I got a load cell out of a load cell from a kitchen scale. This scale didn't quite meassure correctly anymore, so I'm wondering if it is due to a broken load cell or faulty electronics.


EDIT:

Question

I probably need a volt meter to test the load cell?

 

[pilmat]

This is in answer to Derek Speare's question from here: Hydraulic Brake Build (post #76)

Why hydraulic brakes (or at least hydraulically actuated sim brakes)?

At first I was skeptical as to the benefit. The hydraulic system is in fact just a spring operated system: hydraulic fluid is pushed from the master cylinder to the slave cylinder, where the slave compresses an elastomer stack (spring material). A fancy way to actuate a spring

Derek argued that it is not the spring, but the way the spring is actuated that gives hydraulics their ultimate-ness. Without first hand knowledge, and knowing full well he had first hand knowledge, I decided to put my access to race parts to my advantage and and go to school

To not clutter this thread, as it has lots of good info and opinions, I started the Hydraulic Brake Build. That has hit another small setback , so I'll take a few minutes and tell you what I've found so far.

Feel is everything
When I started this thread, I wanted to say that all brake solutions are essentially the same, measuring how much deflection there is in a spring. As I just said, the hydraulic brake seems to do the same thing, and does at its base. What I didn't know but suspected, was that the feel of application would be similar with hydraulics as with a spring (especially a non linear one) and a load cell would be similar. In fact it is a bit different, there is a improved progressiveness of the pedal and you feel the car "load up" in a much more realistic way. I put this down to the damping of the fluid and the natural damping within the elastomer.

The next step is where the hydraulics take you to a new level: modulation and release. Once I tuned the master cylinder diameter to the slave, the feel was exceptional in this aspect. Little small PRESSURE changes affect to the brake on screen. Threshold braking now became a repeatable reality And the ability to trail brake the car smoothly into the car is sweet

I don't know how much faster it made me, but it made me much more consistent!!

So it comes down to a stronger feeling of connection between what is happening on the screen and how your body can react to it BEFORE you get into trouble.


My testing was cut short by a failure in the stock pedal base plate. I have a new one being produced as we speak, more details (and eventually a video ) will follow when I get it back together towards the end of the week.

Impression so far? SWEET

Let's keep this going

 

[derekspeare]

This is in answer to Derek Speare's question from here: Hydraulic Brake Build (post #76)

Why hydraulic brakes (or at least hydraulically actuated sim brakes)?

At first I was skeptical as to the benefit. The hydraulic system is in fact just a spring operated system: hydraulic fluid is pushed from the master cylinder to the slave cylinder, where the slave compresses an elastomer stack (spring material). A fancy way to actuate a spring

Derek argued that it is not the spring, but the way the spring is actuated that gives hydraulics their ultimate-ness. Without first hand knowledge, and knowing full well he had first hand knowledge, I decided to put my access to race parts to my advantage and and go to school

To not clutter this thread, as it has lots of good info and opinions, I started the Hydraulic Brake Build. That has hit another small setback , so I'll take a few minutes and tell you what I've found so far.

Feel is everything
When I started this thread, I wanted to say that all brake solutions are essentially the same, measuring how much deflection there is in a spring. As I just said, the hydraulic brake seems to do the same thing, and does at its base. What I didn't know but suspected, was that the feel of application would be similar with hydraulics as with a spring (especially a non linear one) and a load cell would be similar. In fact it is a bit different, there is a improved progressiveness of the pedal and you feel the car "load up" in a much more realistic way. I put this down to the damping of the fluid and the natural damping within the elastomer.

The next step is where the hydraulics take you to a new level: modulation and release. Once I tuned the master cylinder diameter to the slave, the feel was exceptional in this aspect. Little small PRESSURE changes affect to the brake on screen. Threshold braking now became a repeatable reality And the ability to trail brake the car smoothly into the car is sweet

I don't know how much faster it made me, but it made me much more consistent!!

So it comes down to a stronger feeling of connection between what is happening on the screen and how your body can react to it BEFORE you get into trouble.


My testing was cut short by a failure in the stock pedal base plate. I have a new one being produced as we speak, more details (and eventually a video ) will follow when I get it back together towards the end of the week.

Impression so far? SWEET

Let's keep this going

I think I must print this out and frame it!

 

[LogiForce]

*starts pondering if the next advancement is sim brake systems will be to rotate one (real car) brake disc according to game telemetry readouts, and use a (real car) brake caliber and hydraulic system to apply brake pressure on a real rotating disc. Though you might want to enclose the disc (due to dust) and add some ventilation.

Interesting read here though. Shame I didn't saw it before.

 

[derekspeare]

*starts pondering if the next advancement is sim brake systems will be to rotate one (real car) brake disc according to game telemetry readouts, and use a (real car) brake caliber and hydraulic system to apply brake pressure on a real rotating disc. Though you might want to enclose the disc (due to dust) and add some ventilation.

Interesting read here though.

The next advancement in sim racing is FFB pedals

 

[LogiForce]

The next advancement in sim racing is FFB pedals

Maybe... though wouldn't this be better fed through tactile+simvibe?
Afterall most (if not all) of the vibrations that get to the pedals (or any other part of the car) travel through the chassis. So raising your rig up on soft vibration dampers and using tactile to reproduce vibrations will make those vibrations travel through your entire rig.

Unless you meant something totally different of course.
Like the feel of the clutch plates gripping and that sort of thing.

I am also still waiting for that gear grinding FFB shifter though, but nobody seems to take up the challenge as of yet. I am sure it can be done one way or the other.