NAME

       evdev-joystick - joystick calibration program

SYNOPSIS

       evdev-joystick --help
       evdev-joystick --listdevs
       evdev-joystick --showcal <device‐path>
       evdev-joystick   --evdev  device‐path>  [--axis  <axis>]  [--minimum  <value>]  [--maximum
       <value>] [--deadzone <value>] [--fuzz <value>]

DESCRIPTION

       evdev-joystick calibrates joysticks.  Calibrating a joystick ensures the positions on  the
       various axes are correctly interpreted.

OPTIONS

       --h, --help
              Print out a summary of available options.

       --l, --listdevs
              List all joystick devices found.

       --s, --showcal <device‐path>
              Show the current calibration for the specified device.

       --e, --evdev <device‐path>
              Specify the joystick device to modify.

       --a, --axis <axis>
              Specify the axis to modify (by default, all axes are calibrated).

       --m, --minimum <value>
              Change the minimum for the current joystick.

       --M, --maximum <value>
              Change the maximum for the current joystick.

       --d, --deadzone <value>
              Change the deadzone for the current joystick.

       --f, --fuzz <value>
              Change the fuzz for the current joystick.

CALIBRATION

       Using  the Linux input system, joysticks are expected to produce values between -32767 and
       32767 for axes, with 0 meaning the joystick is centred.  Thus,  full‐left  should  produce
       -32767  on  the X axis, full‐right 32767 on the X axis, full‐forward -32767 on the Y axis,
       and so on.

       Many joysticks and gamepads (especially older ones) are slightly mis‐aligned; as a  result
       they  may  not  use  the  full  range  of  values  (for the extremes of the axes), or more
       annoyingly they may not give 0 when centred.  Calibrating a joystick provides  the  kernel
       with  information  on  a  joystick's  real  behaviour,  which allows the kernel to correct
       various joysticks' deficiencies and produce consistent output  as  far  as  joystick‐using
       software is concerned.

       jstest(1)  is  useful  to  determine whether a joystick is calibrated: when run, it should
       produce all 0s when the joystick is at rest, and each axis should be able to  produce  the
       values  -32767  and  32767.   Analog  joysticks should produce values in between 0 and the
       extremes, but this is not necessary; digital directional pads  work  fine  with  only  the
       three values.

SEE ALSO

       ffset(1), jstest(1).

AUTHORS

       evdev-joystick was written by Stephen Anthony, based on VDrift's G25manage tool.

       This manual page was written by Stephen Kitt <steve@sk2.org>.