[simpits-tech] Switchs, Rotary and pot
Frank Riedel
simpits-tech@simpits.org
Fri, 16 Aug 2002 08:31:26 +0200
tester !
Frank
----- Original Message -----
From: "Marv De Beque" <mdebeque@woh.rr.com>
To: <simpits-tech@simpits.org>
Sent: Tuesday, August 06, 2002 12:31 AM
Subject: Re: [simpits-tech] Switchs, Rotary and pot
> That is an open question.
>
> The answer is, it depends.
>
> However, you have not qualified the exact application, so it is hard to
give
> you a good answer.
>
> However, since I am constructing a F-16 cockpit, I can tell you what I
plan
> to use. I will use a potentiometer for almost all of my applications
where
> there is a knob. Except....
>
> ... the caveat is there are many knobs that use a rotary switch and I will
> use a rotary switch where it is required. I think you know what a rotary
> switch is, but if not, it is a mechanical switch that rotates to preset
> positions.
>
> There are not too many places where an encoder will be applicable in my
sim.
> I may possibly use them for the ICP panel that sticks in the pilots face.
> There are 4 thumb wheels that control contrast, brightness, and other
> functions on the HUD. An encoder may be physically easier to mount than a
> pot in those instances.
>
> Encoders require more expensive circuitry to operate than a pot. General
> rule of thumb is that there should be a good reason for using an encoder
> where normally a pot will not do.
>
> I would recommend a pot.
>
> That being said, from the scope of the questions you are asking, I wonder
> where you are at in your project and what your project goals are? I ask
> because I get a sense that you might be putting the cart before the horse.
>
> What is your goal and what is your plan to get there?
>
> I am sure that you can get all the help you need right here, but it is
good
> to get the basics first, outline your goals, and then we can help you
> execute your plan (or at least help you get a plan together).
>
> Marv
> --
>
>
> > From: "Frank Riedel" <frank@rezultat.dk>
> > Reply-To: simpits-tech@simpits.org
> > Date: Tue, 6 Aug 2002 00:09:33 +0200
> > To: <simpits-tech@simpits.org>
> > Subject: Re: [simpits-tech] Switchs, Rotary and pot
> >
> > Great exampels ;o)
> > GOT IT ;o)
> > BUT - can i use POT instead of ENCODERS in my pit ???
> >
> > Frank
> >
> > ----- Original Message -----
> > From: "Marv De Beque" <mdebeque@woh.rr.com>
> > To: <simpits-tech@simpits.org>
> > Sent: Monday, August 05, 2002 11:57 PM
> > Subject: Re: [simpits-tech] Switchs, Rotary and pot
> >
> >
> >> No.
> >>
> >> A pot (short for potentiometer) is a device that rotates over a given
> >> portion of a circle. This is usually about 270 degrees, but there are
> >> multi-turn pots that rotate 5, 10, or 20 turns from lock to lock.
> >>
> >> A pot is nothing more than a resistor that can be changed from zero
> >> (usually) to its maximum value. 100,000 Ohms is typical for simulator
> > use.
> >>
> >> A pot, theoretically, has an infinite adjustment between its two
extreme
> >> values (i.e., 0 to 100,000 Ohms). So, like a faucet (in good working
> >> order), you can adjust the flow to any value in between.
> >>
> >> A rotary encoder is different. It is a device that rotates like a pot,
> > but
> >> instead of acting like a variable resistor, it sends out a set of
pulses
> > as
> >> the knob turns. It is sort of like putting playing cards on the forks
of
> > a
> >> bicycle and turning the wheel. As each spoke passes, an audible click
is
> >> heard (a pulse). You can count the pulses and then determine how far
the
> >> wheel has rotated. You need two two playing cards slightly offset in
an
> >> angular fashion to tell which direction the wheel is rotating. By
looking
> >> at which card clicks first you can tell direction of spin.
> >>
> >> The thing about encoders is that they have a "granularity". Unlike a
pot
> >> which is infinite, there are finite steps to an encoder. There may be
any
> >> number of steps you can get from a few to several hundred steps per
> >> revolution. You can resolve the rotation only down to the step, but
you
> > can
> >> not tell how much an encoder rotates between step steps (i.e., a half
> > step).
> >>
> >> Most encoders do not remember their positions when power to the system
is
> >> turned off. So, the system must somehow save the last known position
if
> > it
> >> is to pick up where it left off at power down. A pot has the same
> >> resistance whether the system has power or not.
> >>
> >> A pot almost always has a mechanical stop. Resistance can only go so
far.
> >> An encoder does not necessarily have a mechanical stop and can be
rotated
> >> continuously without stopping.
> >>
> >> An example of an encoder is a computer mouse (at least the old ones).
> > Some
> >> new car stereos have them too.
> >>
> >> Two different animals that can be used in similar ways and each has its
> >> advantages.
> >>
> >> Sorry for the long message, but I am short on time.
> >>
> >> Marv
> >> --
> >>
> >>
> >>> From: "Frank Riedel" <frank@rezultat.dk>
> >>> Reply-To: simpits-tech@simpits.org
> >>> Date: Mon, 5 Aug 2002 23:35:45 +0200
> >>> To: <simpits-tech@simpits.org>
> >>> Subject: Re: [simpits-tech] Switchs, Rotary and pot
> >>>
> >>> Thanks alot for the explanation ;o)
> >>>
> >>> I found the F16 panels at simpits.org...
> >>>
> >>> Did i get it right - rotary encoders = potentiometers ??
> >>>
> >>> Thanks
> >>> Frank !
> >>>
> >>> ----- Original Message -----
> >>> From: "Andreas Fransson" <andreas.fransson@post.utfors.se>
> >>> To: <simpits-tech@simpits.org>
> >>> Sent: Monday, August 05, 2002 9:09 PM
> >>> Subject: Re: [simpits-tech] Switchs, Rotary and pot
> >>>
> >>>
> >>>> Frank,
> >>>>
> >>>> 3-way switches are (usually) on-off-on. With or without automatic
> > return
> >>> to
> >>>> center position (not sure what the english expression for this would
> > be).
> >>>>
> >>>> Rotaries, if you mean rotary switches and not rotary encoders, may or
> > may
> >>>> not have limits. A couple I have here for example do not. They go all
> > the
> >>>> way around. What they do is just rotate a common ground around a
number
> > of
> >>>> connections. Like a "normal" switch but with many more positions.
Mine
> >>> have
> >>>> 12 I think. You could say that they are "all-on" in the sense that
one
> >>> lead
> >>>> is always active. Encoders are a different breed altogether. They are
> >>>> commonly used to sense motion (rotation) rather than indicate switch
> >>>> positions.
> >>>>
> >>>> "Pots", or potentiometers, are basically variable resistors. I you
use
> > one
> >>>> with EPIC, or as a replacement for a joystick pot, it is 100 ohm
linear
> >>> pots
> >>>> you want.
> >>>>
> >>>> If you use the EPIC, the kind of switches you use are almost
> > unimportant.
> >>>> EPL (the EPIC programming language) is very flexible. It's not at all
> > like
> >>>> the standard joystick momentary on/off pushbuttons.
> >>>>
> >>>> What aircraft (or whatever) panels are you looking for?
> >>>>
> >>>> Andreas
> >>>> http://valhallainc.d2g.com
> >>>>
> >>>>
> >>>> From: "Frank Riedel" <frank@rezultat.dk>
> >>>>> Hi All !
> >>>>>
> >>>>> 3 way switchs - is that off-on-off or ????
> >>>>> Rotary - is that 360 dg. or ???
> >>>>> 2 way switchs - is that on-on or ???
> >>>>> Pot - is that a normal potmeter 100 ohm or ???
> >>>>> Is EPIC control all those switchs nomatter if it is on-of or on-on
???
> >>>>>
> >>>>> Do anyone of you guys have a link to a page where i can read about
it
> >>> ???
> >>>>>
> >>>>> and do anyone have a set of drawings of panels without knobs on ????
> >>>>>
> >>>>> thanks for all your help... i'm on the road for my first real pit
;o)
> >>>>>
> >>>>> Frank
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
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above
> >>> page. Thanks!
> >>>
> >>>
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> >>> Thanks!
> >>
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