Oh, and don't forget a DC blocking cap since the input of the amplifier exp=
ects AC.

----------------------------------------
> From: lgtngstk@hotmail.com
> To: piclist@mit.edu
> Subject: RE: [EE] Force-feedback signal?
> Date: Tue, 9 Sep 2014 11:19:21 -0400
>
> I'd say the easiest by far would be to open up the steering wheel and fin=
d the rumble motor. Then use the voltage or PWM going to the motor as an in=
put to a PIC. A square wave sounds more like a job for the digital output t=
o me, then through a divider or whatever to get the right signal level to t=
he amp. It sounds like different frequencies generate different rumble leve=
ls, so maybe a varying frequency depending on the desired effect.
>
> ----------------------------------------
>> Date: Mon, 8 Sep 2014 15:49:47 -0400
>> From: picdude3@narwani.org
>> To: piclist@mit.edu
>> Subject: Re: [EE] Force-feedback signal?
>>
>> I'll add that I'm using a Logitech G25 force-feedback steering wheel.
>>
>> Cheers,
>> -Neil.
>>
>>
>>
>> On 9/8/2014 2:44 PM, Neil wrote:
>>> Hi All,
>>>
>>> Need some quick assistance for a project I'm taking to the Orlando Make=
r
>>> Faire this coming weekend... I'd like to add seat vibration to a race
>>> car simulator, which is essentially a PC-based race car game, race seat=
,
>>> force-feedback steering wheel, pedals and gear-shift, but with real
>>> gauges instead of the usual on-screen ones. For the curious, gauge data
>>> gets dumped out of the game (LFS) to UDP, Python takes that and spits i=
t
>>> out the serial port, a PIC18F takes the serial data and converts it int=
o
>>> a digital stream with 6 parameters, and each of the 6 gauges on the das=
h
>>> will grab whichever piece of data they need from the bus stream.
>>>
>>> This is what I have for the seat vibration...
>>> http://www.thebuttkicker.com/gamer2 . It's essentially a subwoofer
>>> that's bolted under the seat, but there's an issue in that it uses line
>>> level audio for it's input so connected to a speaker output, it rumbles
>>> more (due to wind, engine and some road noise) as the car goes faster,
>>> and that's out of sync with what's expected... ie: rumbling/jolting whe=
n
>>> the car goes off-road. The force-feedback signal that goes to the
>>> steering wheel has the rumbles/jolts correct.
>>>
>>> I've connected the buttkicker input to a function generator and a
>>> low-frequency (~30 Hz) signal produces a nice rumble... even a square
>>> wave works well. But now I need to get the force-feedback signal to
>>> modify the amplitude of a square-wave signal I generate. There are two
>>> options I can think of...
>>> (a) Grab/convert the motor signal (from inside the force-feedback
>>> steering wheel) and have that modulate the square wave.
>>> (b) Use acceleration/velocity data from the game (which I can get and
>>> also dump out the serial port) to modulate the square wave.
>>>
>>> Any of you know about these force feedback wheels and can tell me if (a=
)
>>> will be relatively simple? IE: can I just isolate and filter the motor
>>> signal to get a signal whose amplitude varies with the force that the
>>> game is applying to the wheel? That would then go into an op-amp
>>> voltage-controlled amplifier to drive the butt-kicker.
>>>
>>> If I use the data from (b), I can have the same PIC generate an analog
>>> output (proportional to how much rumble is required) and a separate
>>> 30-Hz square wave. Both of those would go into a VCA also as in (a).
>>>
>>> I have only a couple days to do this, so any help in figuring out the
>>> easiest path here or any other options would be appreciated.
>>>
>>> Cheers,
>>> -Neil.
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
 		 	   		 =20
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.