[slinkelist] IR distribution, wireless keyboards, Mouse Emulation

[Thomas W. Humphrey]

Christoph Aeschlimann posted:
"2) My whole installation is now in one room. In another I have a beam for
TV
and Computer-Screen. For controlling the computer I'm using a airboard
(silitek SK-7100). I send all the commands to a slink IR receiver and from a
slink transmitter to the original airboard receiver. Well, this is working
but when I move the mouse, sometimes the cursor jumps around. And sometimes
I have to press the key a second time. Has anyone else made some experience
with a similar configuration?"

There are various problems combining a wireless keyboard with the slinke
and/or with infrared distribution systems.  I have been working this problem
for almost a year now.  Here's some collected wisdom.

Typically there is noise in an IR distribution system that interferes with
the essentially continuous IR streams that are produced by the keyboard,
particularly when there is mouse movement.  A good way to check for noise is
to put the IR distribution system's output opposite the slinke's IR sensor
and see if the slinke activity light glows orange, even when there is
(should be) no IR activity.  If the slinke is showing orange, you've got a
noise problem.

IR noise often comes from the TV(s) set at the remote location(s).  Try
turning off the TV(s) to see if the noise stops.  If it does, try moving the
remote IR sensor(s) away from the TV or shielding it from direct exposure to
the TV screen.  Same procedure for a computer monitor if you have one.  I've
also heard of fluorescent lights (such as used in a fishtank) producing IR
noise so check those too.  Also, the sensor(s) at the remote locations
should have no direct exposure to sunlight.

You may ask, if the TV is making the noise, why doesn't the noise prevent
the TV's own IR remote from working?  The answer is that IR mouse movements,
and to a less extent, IR keystrokes, use long IR sequences.  E.g. the IR
stream tells the computer when a key goes down, and when the key comes up
again, how fast to move the mouse, when to change directions, etc.  Noise is
far more troublesome to such long, timing sensitive sequences than it is to
short codes such as are produced by a typical consumer electronics remote
control.

IR noise can also be produced by RF interference in the power supply to the
distribution system or components.  I found that I had this problem; even
when everything was turned off and all inputs were disconnected from the
distribution system, I still had noise.  I solved this problem with a
RadioShack power supply filter.  They are sold for Notebook computers but
also help with other units.

There is a separate problem as well.  Slinke doesn't take kindly to exposure
to the kind of continuous IR that is produced by mouse movement on an IR
keyboard.  The Slinke tries very hard to decode all IR it is exposed to, and
can be overwhelmed by the barrage of IR that comes from mouse movement in
particular.

Of course, you often want to send IR commands to the slinke, e.g. to control
playlists, etc.  If you also want to use the keyboard, you have a catch 22.

One solution to this problem is to use an RF wireless keyboard instead of
infrared.

Another solution is to use MousEmu (the Mouse Emulator), the slinkx program
another programmer and I have been developing for some months now, to
control the mouse movements and mouse buttons with slinkx events.  This
permits you to use a handheld infrared remote control to move the mouse and
do clicks and drags, which is sufficient for nearly everything you may want
to do in CDJ.  When you use MousEmu to control the mouse, the slinke only
receives occasional discrete IR codes rather than a barrage of IR like a
keyboard or mouse would produce.  So, the slinke is much happier.  In my
experience, keystrokes at the IR keyboard are not nearly as problematic for
the slinke as the mouse movements, so if you can avoid moving the mouse with
the IR keyboard, you will probably be just fine.

The MousEmu program is being debugged and I will post it at Nirvis when I
think it is done.