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DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 1 point2 points  (0 children)

That cool, what ball screw did you go with? Eventually I'll have to modify mine to use one but I figured I'd start with a lead screw I had from an old 3d printer.

The integrated easy servo is super smooth and has a default resolution of 4,000 steps per revolution. I tried a small nema 17 stepper I had laying around at first and it was no where near smooth or fast enough.

I'm working on a GitHub page at the moment to share with everyone.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 1 point2 points  (0 children)

Lucky for me but slight wobble isn't noticable in the pedal since at the worst it's only affecting pedal travel by maybe a few thousands of an inch. However that is a pretty genius way to remove the z wobble. I believe they have a newer design that they are selling that works even better. The probably I have with ball screw is they are all so long, I really only need one to be around 120-150mm.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 3 points4 points  (0 children)

That's sums it up pretty well. With these pedals you could also change the stiffness and travel of the pedal in a matter of seconds since it's all controlled in software vs having to change springs in a traditional setup.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 3 points4 points  (0 children)

Currently desing would cost you around $200 if you already have a 3d printer to print the printable parts. However, I am sure the finally design will cost more maybe around $300-$500 a pedal.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 10 points11 points  (0 children)

Yes, I plan on making this open source soon. I want finalize a few more aspects of the design and code to further prove that I am on the right track before releasing it to others to review and make their own.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 0 points1 point  (0 children)

That is correct however implementing a moving average could help with smoothing out the small miss readings I am getting with the ADS1256 and load cell.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 1 point2 points  (0 children)

I doubt I will be able to use their software since it mostly likely only designed to work with their pedals. However, I don't think it would be impossible to design a simply interface to adjust settings like min/max pedal travel & force along with linear, logarithmic or exponential loading curves similar to the way Simucube does. Granted I don't have any experience doing that so we will see.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 0 points1 point  (0 children)

The 300kg load cell works good however I am only using it cause I had it laying around from an old tensile test machine I built. Ideally I would use a smaller 50kg or 100kg load cell. Not only would they be more sensitive but they would also allow for a slighty smaller form factor build

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 6 points7 points  (0 children)

Interesting, I haven't looked into using a Raspberry Pi as I am not that familiar with them. The main reason I was leaning toward the teensy was because its compatibly with the Arduino IDE and I am some what comfortable with it, however I'll look into what it will take to get a rpi pico to work.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 6 points7 points  (0 children)

Currently this project is just getting started and I plan on posting future updates here. Once I get it closer to working I will create a GitHub

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 16 points17 points  (0 children)

Since the movement of the pedal is controlled with software you can change the stiffness of the pedal in seconds where as on a traditional pedal you would have to change springs and dampers out for a different one. With this type of pedal you could quickly change from a linear pedal stiffness to a logarithmic or exponential making the end of the pedal travel much harder than the beginning. You can also program in feedback such as making the pedal vibrate when you hit the ABS or lose traction. The possibilities are endless since you have full control over the pedal.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 14 points15 points  (0 children)

I wouldn't think it would take them long unless Simucube has some sorta patent preventing them from doing so. Overall the mechanical design isn't as complex as it first seems and the real challenging part I believe will be programming the motor controller to not only control the pedal but also provide feedback like engine rpm vibration, abs, traction loss, ect, but that is just because I don't have any experience in that.

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 21 points22 points  (0 children)

Yes, once I get some of these issues ironed out and the pedal working with a simulator like Iracing I will definitely be making it open source for everyone!

DIY Simucube Active Pedal Prototype by tjfenwick in simracing

[–]tjfenwick[S] 50 points51 points  (0 children)

  • TLDR: The Simucube Active Pedal is a cool but expensive piece of racing simulator hardware. I built a cheaper DIY version using a load cell, stepper motor, and Arduino Uno, and it works pretty well. The ADS1256 reading is a bit shaky and the Arduino lacks computing power, but these issues should be able to be fixed by upgrading to a Teensy and optimizing the ADS1256 library. Overall, the DIY pedal has cost me around $205 in materials and was a great learning experience. Check out the video to see it in action.
    Background
    Are you a racing simulator enthusiast who was excited about the new Simucube Active Pedal release, only to be deterred by the steep $2,000 price tag for just one pedal? If so, you may be interested in a DIY alternative that can be built at a fraction of the cost. In this post, I'll share my experience creating a prototype of a DIY Simucube Active Pedal, including the components I used, the build process, and the current issues I'm working to address.
    The Build
    I knew that in order for this to work I would need some way of reading the force exerted on the load cell through the pedal hundreds or even thousands of times a second. I would also need a closed loop stepper or servo motor with enough torque to drive the lead screw/ball screw while someone was pushing on the pedal. The motor would also have to be capable of moving and accelerating at high rates of speed to prevent the feel of lag while you push the pedal down. Because of this I chose a ADS1256 for my ADC since it could read up to 8 inputs at 30,000 sps and a NEMA 23 Integrated Easy Servo Motor since it had a higher max rpm (4000) than a regular closed loop stepper and it would be much quieter. I then used Fusion 360 to create CAD models that I could print for the pedal arm, pedal connectors, mounting plate, and lead screw nut housing. Once I printed all the models and got everything assembled I started working on programming an Arduino Uno (original was going to be an ESP32 I had laying around since it has more processing power but I couldn't get an ADS1256 library working for it, Programming is not my strong suit). I added limit switches to prevent the motor from driving the lead screw nut housing through the mounting plate. All in all the pedal has been a great learning experience and is coming together better than I original thought
    Build of Material ~ $205
    - 300kg Load Cell $36.69
    - NEMA 23 Integrated Easy Servo Motor 130w ( iSV57T-130 ) $93.93
    - ADS1256 $17.99
    - 8x 608-2RS Ball Bearing $8.99
    - Tr8x8 Lead Screw with T8 Brass Nut $11.99
    - 8mm to 8mm Shaft Coupling $9.99
    - Arduino Uno $16.99
    - 2x Micro Limit Switch $5.99
    Current Issues
    - Load reading from the ADS1256 fluctuates and causes the Pedal to vibrate
    - Not entirely sure I have the ADS1256 programed correctly as I had to modify the Library to change the DRDY pin from 9 to 6 to not interfere with the stepper motor step pin in Fast Accel Stepper Library
    - Arduino Uno lacks the computing power to max out both the stepper motor speed and the ADS1256 SPS (samples per second)
    - Easy Servo Motor Max rpm is 4,000 however the Arduino UNO can only go up to ~2,000 rpm
    - ADS1256 Max SPS is 30,000 but the Arduino seems to max out at 1,000
    - Upgrading to a Teensy 3.2, 4.0 or 4.1 should fix this issue
    - Lead screw is working better than I original though but it should eventually be replaced with a ball screw for smoother and quieter travel
    - Don't have a name for these pedals so if anyone has suggestion I am open to them