Adding Rev Lights And Gear Selector To Ms Wheel?, Building a F1 wheel for the 360.... Options

[mikesnowdon]

Hi Christian.

Thanks for your comment!

Why did you decide to stretch the motor impulses?

Cheers,
Mike.

[mikesnowdon]

I may have found a free hack to get stronger Force Feedback!

Earlier in the thread RDC told me to have a look at the section in the 3950 datasheet regarding the SENSE resistor (Pin 7 to Ground). Initially I didn't understand what I was reading....

However I just read the article below*** and found out it is basically sets the current that the driver outputs to the motor. By removing it and connecting pin 7 directly to ground the full 2.8 amps will be available. I haven't tested this as Im worried about killing the PSU as the more current the driver produces the more the the PSU will need to deliver.

*** http://ebldc.com/?p=73

Now if Volts determine how fast the motor spins, and Current determines how much torque it can produce, then simply changing the PSU for a eg: 30/32v 5a one and bypassing the SENSE resistor the FFB should react faster and with more power.

Bare in mind if you have the V1 wheel I dont think there is a SENSE resistor (or breakout diodes on the driver output)

I'll order a new PSU asap to test this out and report back

Another thing to consider is that the driver ic will run hotter so might need extra cooling to cope. Otherwise the protection circuits will kick in and the driver will shut down.

This post has been edited by mikesnowdon: Aug 4 2012, 08:35 PM

[doctormord]

Hey mike,

the pulse needs to be stretched as the dI/dT is to low for the given original signal. Without doing this, a stronger motor wont spin. The original motor is a multipole-motor, the normal/other ones dont have that much poles.

If you rise the dV, shorter impulses will also work, but then you'll need to sense the current again to not burn the windings.

Regards, Christian

[mikesnowdon]

I found some more good info on the A3950 here:

http://servo.texterity.com/servo/200904/?folio=50#pg52

I just need to order some parts now and start testing things out

[mikesnowdon]

My force feedback stopped working! Wheel steers ok and everything works but theres no force feedback. There is 24v going to the motor but the motor does nothing exept make a faint whining sound. It doesn't move when power is fed to it. The wheel turns freely in one direction but there is a little 'friction in the other. When turned in the direction with the friction the whining sound stops momentarily. I think the motors gone pop.

Weird thing is I was using it last night and had no issues, then today plugged it in and this problem is there. WTF!

May just give up on this and get a Fanatec CSR......



This post has been edited by mikesnowdon: Aug 28 2012, 06:18 PM

[mikesnowdon]

Christian,

You replaced the motor in yours, do you happen to still have the original one?

[doctormord]

Yes, i still got mine here.

You need?

Drop me a message.

Cheers

This post has been edited by doctormord: Oct 15 2012, 07:50 PM

[mikesnowdon]

Hi all. Got a new wheel. Motor was fine on my other one so must have been something else went wrong....

So lucky for me I have a spare motor, driver, and PSU. So far I have managed to mount the second motor on the back plate. Without increasing the power driving the motors there isnt any noticeable gain on FFB strength yet. Planning to mod the old board which died (hopefully the driver is ok) so each motor has its own driver and PSU.



In the meantime I decided to modify my pedals slightly.....

http://www.youtube.com/watch?v=SU-S1-LDK6c

This post has been edited by mikesnowdon: Jan 13 2013, 07:13 PM

[mikesnowdon]

Decided 2 motors is not the way to go. There is a thing in motors called 'cogging'. Its the resistance necessary to turn the motor spindle when its not powered. Having 2 motors doubled this cogging effect and made the wheel feel slow and sluggish and took away the subtleties of the FFB. Going to stick with a single motor and go ahead with the driver chip upgrade as mentioned above.

The pedals are working well now. Taken a lot of fiddling to get them working right but they are just about there. Next up is to build a buffered r/c filter to smooth the spiky output from the potentiometers.