DIY FFB Steering wheel (MMosFFB ) (In Progress)

Hi ! I received the bts7960 this morning, would you have a shematic ? I am trying to use H-bridge configuration in mmos force feedback panel, but I am not sure about the wiring..
Am I right :
PWM 1 (PE9) = PWM right signal
PWM 1 N (PE8) = DIR Right signal
PWM 2 (PE10) = PWM left signal
PWM 2 N (PE11) = DIR left signal
?

Almost... try this:

PWM 1 (PE9) = PWM right signal
5v = DIR Right signal
PWM 2 (PE11) = PWM left signal
5v = DIR left signal
GND = GND

Thanks ! It works. I am wondering how to wire my g27 pedals to the STM, I got those wires coming from the DB9 plug. I tried everything based on what I found on the internet but nothing works properly...

G27
Please check before start (There may be a difference of models). Begin the study of the wires from these descriptions:

Pedals
yellow throttle
orange brake
red clutch
black gnd
green / brown VCC


Shifter
db9header
red vcc
black gnd
orange X-axis
gray gnd
brown vcc
yellow Y-axis
green clk
blue data
purple sh/lh

Wheel Buttons (I think, I had noted, but I'm not sure if it's on this circuit, please check.)
GREEN PL (sh/lh)
ORANGE CLK
BLACK GND Gnd
ROXO DATA 6
RED VCC

Thanks !

I got the brake pedal working well, accelerator is more problematic, but maybe the potentiometer is defective.

I started to wire the shifter following that schema :
SCK Disco PA5 G27 DB9 Pin 1 (Grey wire) (Pin 7 on G25)
MISO Disco PA6 G27 DB9 Pin 2 (orange wire)
CS Disco PA4 G27 DB9 Pin 3 (Purple wire)
PotX Disco PC2 G27 DB9 Pin 4 (blue wire)
GND Disco GND G27 DB9 Pin 6 (black wire)
Vcc Disco 5V G27 DB9 Pin 7 (red wire) (Pin 1 on G25)
PotY Disco PC1 G27 DB9 Pin 8 (yellow wire)

But it looks like there is some missing wire compared to your informations...

Also, can someone explain why there is often two vcc wires ? I think that in most case, one would be enough ?

PS : In one week :
- I burned my G27
- my mother board died
- I was waiting for my Pimax 5k+ saturday. The tracking says : delivered, but nothing here... I think the delivery man stole me.

Hello everyone, i have a question i can use the stm32f103rcbt6 maple mini with the firmware MMos ? this board have a Cortex M3 with 72mhz and 128kb of flash

Hi ! I didn't find so much informations about mcp23s17. I would have three questions :
1) Why is there a 100nf capacitor needed
2) What is the difference if we pin th mcp to 5V instead of VDD ?
3) Is it normal that pin MISO and MOSI are linked (test with multimeter continuity) ?

1) Where is this capacitor? Maybe it's to reduce the noise and to avoid random buttons.
2) VDD is VCC, which is the same thing as continuous positive voltage, 5v.
And VSS or GND is the ground, negative of power.
3) These ports have square wave output oscillating at a frequency at which a multimeter cant detect. To see this pulse you need an oscilloscope.

why you dont buy cheap STM board for MMOS like this:


these prices only $7

Thanks for your reply ! I just found out this morning that I ordered MCP23017 instead of MCP23S17. That's the reason why my circuit doesn't work.

Thanks for reply

The project is very good, I'm inspiring it in some aspects (everything practically), but unfortunately the STM32F4 is very expensive in my country (Brazil) and on Ebay it costs about $ 11 and with the exchange rate is very expensive . Arduino Leonardo would be an alternative, but it is limited.

Hello again everyone, I see that there have been many people around since the last time I entered the forum.
My absence was due to a disaster on my computer. I broke the hard drive and lost all the information, programs, 3D files ....
I have resumed the project and the first thing I did was to put an encoder with Z cable of 1000P and it worked everything to me first and also surprisingly well but I keep the button 2 blinking and that I have not assigned any button proving that when I want to assign the controls in the game, this is activated and it does not let me many times assign the control that I want, but it is this button 2 that is assigned directly. Someone has been the same ?

Fit a pullup / pulldown resistor and see if the problem goes away

In the end I did not need it. I have replaced all the wiring and the problem has been solved.
Thank you.

Here's a comparison between a normal T500 and my retrofitted mmos 14.4v version. Mine still uses the same 24v motor and pulley system as the stock T500. I have also added a big heatsink and fan to the motor and taken out the 1080degree rotation limiter inside the wheel shaft as it's no longer needed and could be a huge problem if the electronics malfunction.

Due to the lower voltage, mine has a slower max rpm, but 160rpm is still plenty (for comparisom, the TSPC/TGT is about 140rpm). Mine also reaches 160rpm much quicker than stock, and not just because of the extemely low latency: It's quite clear that the T500 firmware doesn't allow the motor to run 24v with unlimited current - there is some kind of current limiter on the T500 pcb/firmware which probably limits the current flow up to the motors rating of 65W. It wouldn't be too much to assume that all the belt drive wheels have current limiters, otherwise their relatively small motors would overheat very quickly when someone who doesn't know what they're doing tries to run the ffb high.



My version, although running 14.4v, allows the motor to draw unlimited current at stall. I think this means that during peak acceleration and stall, the motor is probably drawing 160w+. Which means that the motor would overheat if sustained at full stall torque for too long. However unless the ffb from in game is set completely wrong, the average current to the motor is likely to be around 50w - this is of course dependent on the car and track.

What this means is that the stall forces on my wheel are over twice that of the normal T500. The motor is effectively running in an unlimited mode, meaning it can more accurately represent the forces in the game by treating high and low current draw equally. It is a substantial improvement.

In addition, the new encoder has a much higher resolution... 23040 cpr.. so with a 300mm rim, that is approximately one count per 0.04mm at the circumference. I think this is 5-10 times the stock resolution.

I'm selling my TSPC now because it's not even close to the power of the modded T500. The only upside to the TSPC is that it has less mechanical friction, but I find setting a negative friction coefficient in Rfactor2 FFB settings can pretty much overcome this for the custom T500. The TSPC's motor is very notchy, whereas the T500 motor doesn't seem to have any notching (though as a brushed motor, there is a little bit more friction)

Hi all !

Is there a way to use only one USB cable instead of two for the STM32f4 ?

I dont understand, are you using the discovery version?
USB is required to record the code and another for communication. After recording the code, it can be removed and only use the communication.

Ok thanks. Yes I use the discovery. But if I remove the mini usb cable, it requires an external power source, right ?

Lovely ideas.

Hi
I bought three phase rotary encoder omron E6B2-CWZ5B but it doesn't work well with this software.
When i try to rotate encoder, triangle in WheelConfig rotates too, but it sometimes "jump"

Is there any way to fix it?