$450 Mige Direct Drive Wheel using MMOS and AASD

@wannabeaflyer2,

I know for sure that you are right. I located the sound and it is indeed coming from the Servo Driver. I thought (hoped) that damping the signal (2Kohm and 1µF capacitor) also would do something with the Driver.

I'm just going to build a small box for the driver to keep most of the noise out.

For the rest, I love the build. It is rock solid and bloody strong.

Thanks for the info.

Bakhol

@wannabeaflyer2

10KHz noise is also present during jog test.
If not at jog test,it's something else.

Do to the position if you perform the JOG test ( you sit right next to it) the sound isn't hearable ( but most likely it is there) but in the seat you can hear it.
If i tillt my head...it is gone. Sometimes you have to search for it by changing your head with some degrees.

for me I'm pretty sure the 10khz whine is not audible during jog test with the stm32 disconnected.
it's only audible when i have the stm32 board connected. however, it does come from the servo drive. afaik it's due to the internal 10khz PWM signal used by the drive for something so we can't do anything about it.

It was mentioned on Thanos' discord server that AASD is working on a new version of their servo drive stage, hopefully that will use a PWM frequency inaudible by humans.

Cheers,
I am currently also building this setup using a Big Mige (130St-15015) and a different Servo Drive as well as a Disco Board. I am now trying to convert the PWM signal of the Discovery board to an analog one by using the LTC2644 DAC. Can someone give me the schematics used to accomplish this? For example like the DAC from @Thanos . Also I want to boost the output voltage closer to 10V. Is an Opamp good for that purpose? Of yes, which one and how should I wire it up? I would be very happy to get some answers and am really looking forward to finally hooking up my Servo Drive to my Disco board.
David

Welcome to the forum !!!
Do you have the LTC2644 ?? It is so tiny it is not easy to work with..
Not sure about the opamp..

First of all, thank you for your fast answer.
Yes, I have the LTC2644. I have no problem soldering it to a board with TSSOP pins ($0.5) and then using its bigger connections to create a circuit like shown in your picture. I just wondered, whether it was the right circuit for this application (which you now confirmed, thank you again).
I found an AD711 Opamp and hope it will be able to handle this job, as I have no experience when it comes to choosing the right one for a certain application. I will try a circuit like the one shown in the picture below and keep you updated. Do you see, whether there is anything wrong with it?

@David Böttger That looks good. I would think the schematic is missing some bypass caps and does not show how to hook up the vcc ect.
I too have never played around with opamps other than to solder them into other peoples circuit designs...
However you have sparked my interest lol
I ordered these pre-made circuit boards to play around with..
This stuff is very cheap on Amazon for us here in the US..
Yes, keep me informed.
www.amazon.com/NOYITO-Signal-Amplification-Operational-Amplifier/dp/B07D1VXRDL/ref=sr_1_2?dchild=1&keywords=AD711+Opamp&qid=1603195060&sr=8-2

@T R Para
The Vcc of the opamp is usually never shown in schematics for the sake of simplicity, but very simple to hook up.
Thanks for your tip with bypass caps, I totally forgot about them. I found a great Website that explains why you need them in case someone is interested.
Now I’m just waiting for the parts to arrive and give it a go.
I’m glad to hear that I sparked your interest for Op amps and that you even ordered the same ones as I have. I hope they will work fine.

@T R Para
I had to add the Link in another Post, as you need 3 Posts to be verified for that.
https://e2e.ti.com/blogs_/archives/b/thesignal/archive/2013/04/23/bypass-capacitors-yes-but-why
Have a nice day,
David

Hi everyone!!

I just discovered this post and I am trying to decide if this is for me or not. So, if you excuse me, after reading all 17 pages straight on... I have some questions... a... a lot of them!! So...

1. So I get that all this 10.000 cpr vs 40.000 cpr or... 8M cpr could be a thing but... I have a TS-PC racer right now... so... 10.000 cpr is still gonna be a huge bump up isn't it? and more brute force and fidelity because of the DD... am I getting this right?

2. From the videos I watch (and due to soldering and wiring not being between my strengths) I guess I will need the @Thanos PCB + DAC... Are them still available or will be? When ordering it... does it came with the discovery stm32 or do I need to order that aside?

3. How this project will stand in terms of upgrading in the future to simcube? I mean, if ever necessary... what will I need to order in the future? I guess I can keep the servo and... what more?

4. I readed one post that scared me a lot. Someone stated that better to go the bluehid route in order to make buttonboxes and so wireless... because of this motors not having physical end-stop... is this... a thing? Because I love to make DIY rims and... all of them are cable powered... any of you use cable powered wheels or buttonboxes?

Sorry for aaaaaall the questions buds... this seems like I finally found a way to get into DD (while preserving my GF) and I would love to have all the facts right before bitting this still affordable still expensive bullet...

And anyway thx you all for such an impressive community you have here!!

@Ngry Yellow

Welcome to the forum my friend..
I might be able to answer a few of your questions...

1) I believe 10,000 cpr would equal taking 1 degree of resolution and dividing that degree into 7 segments of additional resolution. That is pretty good resolution. There is no doubt in my mind that there are some people that could feel the difference but I think they would be the exception..

2) The Thanos board is complete. It is preprogrammed with the proper software,the DAC, and all the connectors soldered on. I would just get on his notification list. I doubt it would be a long wait..

3) The software used is a few years old (2014) and open source (I think). It still works well. I do not think it could be upgraded to simcube software as that is surely proprietary.

4) You are correct there are no physical hard stops. You could certainly add a physical hard stop. The MMOS software used does have hard stops built into the software and they work great. But there is always the possibility that the wheel could go for a "spin" all by itself and damage the cable.
The Bluetooth solution is of course wireless and fairly easy to implement.
It is truly a good solution but certainly not the only solution.

Good luck with the project.
Keep us informed

@T R Para so... you have been added to my "to hate" list... I trully was expecting someone to prevent me for doing this haha.

Regarding the resolution... yes... that explanation has convinced me... I do not thing that driving a gt3 around Nordschelife at 280km/h is a situation on where you re going to be able to decide if you want to take that turn at 457'700 degrees of wheel rotation... or at 457'758 degrees of rotation... you just turn and pray

Regarding the upgrade... my concern was more about keeping the Small Mige and try to find the "other thing" (I am not sure how it is called haha the one with the small led display where you tune in the values) The guys from sim-pli.city sell a DD wheel that is based on the Mige 130 so... I was wondering if in the future I would be able to order just the "control unit" and run the Mige.

I am almost decide to do this... gotta check delivery cost... and... voltage and that stuff because I am from Spain and I do not know if all this stuff linked here is gonna work here (in terms of AC, volatge, tension... all that stuff)

Thx for the fast and detailed response mate!!

@Ngry Yellow
AASD and MIGE are different
I don't know if AASDmotor fits

The AASD servo drives just need single phase 220v mains (can work on 110v too).

They come on various sizes, for Direct Drive usually 130ST models motors that have large flange. On my tests used a 90ST that I had spare from actuators (on video)

I found this project from youtube.

tutorial
https://drive.google.com/drive/folders/16qBwewArJznSIwluOPdM2UJBk7X2ITAH?usp=sharing

I just read about the VNMCar Simulator Firmware and joined the Discord.
It seems to be a superior firmware compared to MMOS and also it is still in progress and being updated regularly. What do you guys think about it. Besides that it features an inbuilt DAC so I wonder, whether the external one would even be needed. It might be better in terms of precision, though I am not sure about that.
David.

Perhaps it would be possible to use Arduino?

Woohoo let the fun begin, DHL just dropped off my 130ST, have the Thanos board, now to machine up a wheel hub and fabricate a motor mount for my rig! I've surpassed the $450 bench mark though . . .

I tried using MCP4725 12bit DACs with Arduino and the onboard DAC of the Arduino Due in 12bit mode with this, and did not work very well.

For arduino leonardo/uno etc the AnalogWrite() resolution of most arduinos is 8bit which I think would be too low for smooth force feedback as you can only have 255 unique values for the output voltage and would probably result in very choppy/erratic ffb.

The stm32 microcontrollers have an onboard 12bit DAC.