[PD] joysticks with hid
Hans-Christoph Steiner
hans at eds.org
Sun Jan 29 03:19:25 CET 2006
This is a bit of a quandary. Currently [hid] maps all buttons to
btn_0, btn_1, etc. whether its of the type BTN_MISC, BTN_MOUSE,
BTN_JOYSTICK, BTN_GAMEPAD, BTN_DIGI, or BTN_WHEEL. Axes are treated
similarly. This means patches that are written for a gamepad will also
work for a joystick since all of the names are the same. But this
relies on manufacturer following the USB HID spec, which it seems only
50% do. arg.
So with the Microsoft Sidewinder gamepad, they are way off (its a
gamepad, right?). Btn3 is a BTN_MISC type and ThumbBtn2 is a
BTN_JOYSTICK type. So they are using BTN_MISC and BTN_JOYSTICK when
they should be using only BTN_GAMEPAD.
So my grand plan is to have platform-specific classes which give raw
access to the USB HID info (i.e. [linuxinput], [darwinhid],
[windowshid], and [directinput]). I haven't had a need for those yet,
so I haven't written them. But you are in luck, [linuxevent] still
works, and will give you raw access. But keep in mind, [linuxevent]
works differently than [hid], and is deprecated. (Come to think of it,
I'll probably do [windowshid] and [directinput] soon since there are
fundamental problems with [hid] on Windows which aren't quite resolved
yet.
.hc
On Jan 28, 2006, at 5:33 PM, David Merrill wrote:
> Hello again hans & everyone -
>
> I have a little more detail, after some investigation. I found an
> article that describes what I think is responsible for the spurious
> button presses, at:
>
> http://www.linux-magazine.com/issue/04/LinuxUSB.pdf
>
> So it seems that the sidewinder *does* send out buttonpresses when the
> continuous DOF gets near any edge of its range. But when I look at the
> output of evtest, I can see that the button codes for the near-edge
> condition are actually different than the codes for the thumb buttons
> - but I think the [hid] object is mapping the different codes to the
> same output, causing the confusing condition that I noticed:
>
> vertical edge condition: evtest says: 259 (Btn3), [hid] is mapping
> this to the same output as 291 (TopBtn), sending "key btn_3 1" for
> both.
> horizontal: evtest says: 258 (Btn2), [hid] is mapping this to the
> same output as 290 (ThumbBtn2), sending "key btn_2 1" for both.
>
> So is there a way to ask [hid] to not conflate codes 259/291, and
> 258/290? Or to have [hid] just spit out raw codes, rather than the
> processed textual output that I'm seeing?
>
> thanks!
> -David M.
>
> David Merrill wrote:
>
>> Hello Hans, et al -
>>
>> I've got another puzzling joystick bug that's showing up today as i
>> play around with the [hid] object in linux (Ubuntu Hoary, kernel
>> 2.6.10-5-686).
>>
>> I am using a Microsoft "Sidewinder Dual Strike" USB joystick, and
>> after changing the permissions on /dev/input/event*
>> I can successfully peek at the output with evtest, and I can open the
>> device for reading with the [hid] object.
>>
>> The strange behavior is that when I push the continuous
>> input-degree-of-freedom near one edge or another, a *button-press*
>> registers, but I have not pressed any button (I see this buttonpress
>> in both evtest, and hans' [hid] external). The continuous DOF of this
>> joystick has a springy region near the edges where there is some
>> resistance - and I get the spurious buttonpress when I cross into
>> this region.
>>
>> I tried the same joystick in windows, and I don't get the spurious
>> buttonpresses. (I tested it with both the windows control panel "game
>> controllers" interface, and jsarlo's joystick external).
>>
>> Has anyone see this kind of behavior? Any ideas why it doesn't show
>> up in Windows, but does in Linux? I'd be really interested to find
>> out how to fix something like this..
>>
>> thanks,
>> -David Merrill
>>
>> Hans-Christoph Steiner wrote:
>>
>>>
>>> On Apr 8, 2005, at 12:11 PM, august wrote:
>>>
>>>>>> hmm. I have the 'evdev' module loaded, but there is nothing at
>>>>>> /dev/input/event*
>>>>>
>>>>>
>>>>>
>>>>> You need:
>>>>>
>>>>> mknod /dev/input/event0 c 13 64
>>>>> mknod /dev/input/event1 c 13 65
>>>>> mknod /dev/input/event2 c 13 66
>>>>> mknod /dev/input/event3 c 13 67
>>>>> mknod /dev/input/event4 c 13 68
>>>>> mknod /dev/input/event5 c 13 69
>>>>> ...
>>>>
>>>>
>>>>
>>>>
>>>> thanks....I had the devices listed alright....but the permissions
>>>> weren't
>>>> set. maybe someone else is having the same problem.
>>>>
>>>> doing "chmod +r /dev/input/event*" should do the trick.
>>>>
>>>> now, HID works as expected.....but I only get a resolution from
>>>> 0-255 on
>>>> the joystick axis. Is that how it is supposed to be? I thought
>>>> the
>>>> resolution was much higher.
>>>>
>>>> best -august.
>>>>
>>>> _______________________________________________
>>>> PD-list at iem.at mailing list
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>>>
>>> "Supposed to" might be the key word there. That value, AFAIK,
>>> depends on the hardware. I have two joysticks: a Logitech Wingman,
>>> which outputs 0-127, and a Saitek Force 3D, which outputs 0-4091.
>>> This is also why I wrote the [autoscale] object which is used in
>>> the [joystick], [tablet], and [mouse] objects. These objects
>>> always output between 0 and 1, converting the output range of the
>>> device, to resolution between 0 and 1. Then when you write a patch
>>> for one joystick, it'll stick work with other joysticks.
>>>
>>> .hc
>>>
>>> _____________________________________________________________________
>>> ___ ____
>>>
>>> "The arc of history bends towards justice."
>>> Dr.
>>> Martin Luther King, Jr.
>>>
>>>
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>>
>>
>>
>>
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