DIY FFB Steering wheel (MMosFFB ) (In Progress)

There are pictures https://drive.google.com/open?id=1_G_-_kqGZVxCenb7xiu78xC1RdeLc20y

If there were the diode bridge connection schmatics, it doesn't mean that an ordinary AC-DC power rectifier diode bridge, shall be used. This is absolutly wrong application for them here.

Special ultrafast switching diodes are used as the flybacks. And that is the point.

Hello there im new here

Currently having problem with the encoder
Using leonardo and bts7960 as driver
Using aiwave software and hex file(i think you know this)

So do i i need resistor or not bcuz somehow using emc 0.93v lite can detect it while the aiwave doesnt
Link of encoder just in case
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//m.made-in-china.com/product/Lpd3806600bm-G5-24c-Ab-Two-Phase-5-24V-600-Pulses-Incremental-Optical-Rotary-Encoder-813975175.html

Hello there!
Currently progressing here
The current problem solved but now a new problem arised
Im Im using a 150w motor dc with stall current listed as 12.5A
According to the builds ive had seen in this forum,i need at least 30A psu for the motor to work

My question is does combining more 12 v wires will solve the problem or i need bigger amps psu or do i need to build a soft start / like in the forum for the psu to stop shutting down itself when the motor wants to change its direction?
I tried to lower the main gain but failed idk why...
(Im using atx psu for comp btw)

U need to get rid of the pc psu shut down protection. U don't need 30a psu to get start with or at all.
Connect all the wires properly, and don't touch em. And only then turn on the psu. You may need to do it several times, and even without extra work on pc psu, in order it doesn't run in shut down. It is tested and this is working 100%.

Thanks very much
Really appreciated your response

Good to everyone in this post
I'm very curious about this build, I'm looking into parts and it got me intrigued.
For the encoder could it have been attached onto the motor like I've seen on a DD tread? And if so would it be the same process as the DD wheel?

I am not sure what you mean GTFreak. It does not really matter how the encoder is connected, as long as it is turned in direct relation to the physical wheel. It can be direct on the motor in both direct and geared setups. The only difference then is the PPR calculation will need to be done based on any gearing.

It is also worth mentioning that the MMOS firmware triggers on rise and fall of both A and B lines. Therefore, for a '1000 PPR' encoder, the setting is actually 4000 PPR.

On re-reading your post - Did you perhaps mean using something like this?


This example is a treadmill motor. If so, then it's not likely to work well as it will not have enough resolution. You would still need to have a decent ~1000PPR endoder attached. Some motors do have better resolution encoders though.

Hmmm it's like I'm planning on using a 12v DC 150 watt motor with a custom gear set, which estimating should provide around 6-8 NM of torque, what I was asking before if I could attach the encoder on the back of the motor instead of connecting to the gear system and if so how would do so? The reason I want to attach to the rear is because of I want to have a compact build with a small multi-geared system

hi, i've had a small Mige Ollie kit OSW for a long time - 5 years now.
Just wondering - is there any program out there that can log the torque being output from a game?

In that case, yes, it is not a problem. The MMOS software is designed for a DD wheel so the encoder is 1:1 ratio of the wheel. All it means is that you need to set the PPR relative to the wheel, not the motor in the setup app.

i.e If you have a 5:1 gear reduction between the motor and wheel and a 1000 ppr encoder attached to the motor, it would end up as 20,000 ppr in the setup (5 X 1000 but as I mentioned before it detects rising and falling of both A and B so X 4 as well).

If you are going down this path though, I would recommend a lower PPR encoder and you may end up having to use a manual switch for centering. Others can chime in on that though as I only have DD.

Hello Everyone,

I have been reading through this thread for a while and have decided to start a project of my own. I currently have a DFGT that I want to upgrade. I order a STM32 and a BTS7960. I plan on wiring it up with everything else stock so I can learn and verify everything works.

One question I have is a came across a RS-555 motor on eBay. It's a 12v 7750rpm drive. Stall torque is 29.16 oz-in and Stall Current is 15A. Will this be a noticeable upgrade from the stock motor, or should I look for a bigger 755.

Also, thank you for everyone who has provided feedback to this point. I have learned a lot and am looking forward to starting my project.

That does not sound like an overly powerful motor - The OP used a 10k RPM, 90 oz-in motor with a stall of ~60A in his DFGT. What you're describing there seems like it would be a downgrade from stock.

Thank you for your the guide, would you recommend any treads which talks about the Manual switch for centering?

I am worried about the 60A stall though. The OP said there was overheating issues. And recommended a lower stall amperage. Maybe 15A is to low though?
I'll keep looking for now. Thank you.

Not specifically but you'll see in the guides that you use a 'Z' input which is 1 PPR 'reference'. If the encoder (with Z) is mounted on the motor and not the wheel, it would confise the firmware as it is is used to reference the center. Basically every time you power up the wheel, you will need to center it and push a button that is connected between PA3(?) and ground. You will also need a pullup resistor on it. This will then center the wheel in software/firmware.

He was using the MM shield which are expensive and only 30A. You could just use a couple of BTS7960 modules in parallel. I am using 3 on my setup with no issues but they do need a little cleanup work before putting them to real work, this helps with getting them closer to the rated output current. Nameley, remove the BTS7960 chips and flow solder into all the 'vias' on the board to help with heat transfer and use a thermal pad between the back of the board and the heatsink.

Edit: Hint - If you are using BTS7960 modules - Wire the 'VCC' on the modules to 3v and NOT 5v to avoid issues.

Thanks for the tips on the BTS7960. I looked at the originally power supply for the DFGT. It's 24v @ 1A. This seams insanity low.
If I use a 24v @ 8.5A. That's about 200 Watts, right? I read somewhere in here the original motor was 60w, although after seeing the original PSU. I don't see how.

Just be careful - DC motors are not designed to work like we are using them. The motor itself may well have been rated at 60W and driven at maybe 30w at best.

Putting in a 200W motor and trying to run it at 2ooW in stall mode might well kill it (burn and/or fuse out the windings). I am no expert on this specific topic but for example, my DD is a 48v 1000w motor but I am only running it at 12v.

Remember that the energy has to go somewhere. If we stall a motor, all of that energy is given off as heat rather than mechanical energy. Too hot = dead motor.

It was either back in this thread or another MMOS related thread (Possibly this one here) that we discussed this topic.

Hello there!
Im back after a loooong time to update my progress...
After some research i found out that removing ocp is too dangerous so i decided to just modify the psu into a bench psu,thus a q popped in my mind.
Does anybody had done this?
Would like some feedback though.

also im using a rs 775 150w motor dc and
Im thinking of downgrading the motor to drop the stall current and provide just the ffb i needed.However,i think i need opinions from you guys :
1:better stick gear ratio
2:just change the motor lol

Thanks for helping me XD

Hi, Have U found any solution for this huge deadzone? Just change the configuration for testing for same reasons (friction).