P51B Trim Control Panel

[chuckcrc]

Hi all
its taken a while for me to get these pixs together so I hope they will provide some idea on how to construct a trim control panel.
The panel is made out of 6mm 3 plywood and is covered with thin sheet metal which I rivited into the wood to give it that authentic look .
The aileron and rudder trim contorl units drop into the top of the panel  and are easily removed whereas the elevator and Flap control are fixed in. All trim controls and the flap control use 2 bit grey code rotary encoders whereas the gear lever uses a lever switch.
The construction is straight forward , however you must be careful in aligning both metal plates to both can be drilled at the same time to make sure the spacing is correct for the gears otherwise the gears will bind.

If you want more detail about any aspect of the contruction please post your questions and I will try to explain. I don't have any drawings or plans as I made them up as I went along.
cheers
chuck
   
This is the basic encoder module for the rudder/aileron


Looking into the panel to the elevator trim control. I soldered the encoders to a small piece of veroboard and then used molex pins to attach the wires to.

[JBaymore]

chuckcrc,

Thanks for the nice detailed pictures.

Where did you get the gears for the trim wheel assembly?  The way it looks... the large gear is on the trim wheel..... so a small movement of the trim wheel will result in a lot of turns on the encoder.  Is this correct?  Or is there a gearing inside the "black box" hub that we can't see?  What is the encoder interfaced to?

Sorry for a lot of questions  ;).

best,

....................john

[chuckcrc]

Hi John
the gears are out of a HO scale AFX slot car set. They are the gears that are in the manual overhead lap counter. The slot cars pass under the counter and operate a lever overhead which in turn operates via the gears a indicator which counts what lap you are on.The lap counter costs AUD $11 and you get two sets of gears as there are two lanes in the slot car set.

The large gear is perfect fit (6mm) for the shaft of the encoders or standard pot, however the smaller gear has a 4.5mm internal diameter and is a little tricky to make fit. I was able to bore this out to 6mm by using a drill bit in my hand and carefully drilling out the plastic bit by bit. The best solution would be to turn the shaft down on the encoder somehow !
These aren't the best gears to use but I had trouble trying to find some suitable that were not expensive.  

Now as to the gearing ratio I found that when I was testing a prototype of the encoder cct I noticed that the encoder had to pass thru 4 detents to allow for one complete off/on cycle. What would happen is that on detent 2 and 3 the encoder cct would light up the test led and go off on detent 4. This makes sense as it is a 2 bit encoder which means it can decode 4 binary states.
So what would happen is that :
detent 1 = o no output no led lite
detent 2 = 1 output and led lite
detent 3 = 1 output and led still stays lite
detent 4 = 0 no output led off

So I needed to interface this into a bashed keyboard and the problem with bashed keyboards is they can only take a momentary pulse so I could get depending on where the encoder detent was left would be a permanent pulse sent to the keyboard which mean "key repeat" and back to the drawing board! (this is why bashed keyboards are a pain !!!) If you use a Plasma system of Hagstrom this won't be a problem because they only respond once to a change of state.

So after spending countless hours at the drawing board (and a few beers later) I came up with a capacitor operated relay interface driven by the encoder cct that world only send a momentary pulse to the keyboard for every 4 detent movement of the encoder so that's why I have the big gear on the control wheel and the little gear on the encoder.

Wow I hope this makes sense !!


The encoder cct is one that I got from a site I can't remember, however it is a common design they call sin/cosine cct. Can I post it here or will I need the original owners permission.

cheers
chuck

[chuckcrc]

Hi all
I found the web site that has the rotary encoder cct and sent the onwer an email but Ive never received a reply.
So the next best thing is to post a link to the site and anybody who's interested can download from that site.
I have made modifications  to the cct to make it work with a bashed keyboard which I am happy to post but I don't have a scanner, does anyone know of a freeware electronics drawing / cad program that I can download.
heres the link
[http://homepages.ihug.com.au/~pholt/panel.html][/url]

cheers
chuck

[oldhorse]

HI

[chuckcrc]

Hi Oldhorse
great idea over at AVsim. I will look into it. The problem I see with that option for trim control is the key repeat problem. Using that option for your Nav radios is ok because you are looking at a display as it cycles the radio freq you want and when you get the freq you want you would then stop turning the encoders or just turn it one more detent to turn off the key repeat.

With the trim control there is no display etc in the Combat Flight sim to tell you to stop the trim and with key repeat on you would find the a/craft hard to control.
This is why I made up capacitor operated relay driven by a transistor from the encoder cct to give a momentary pulse to the keyboard. With this I can give small adjustments to trim which I can feel thru the force feedback stick. and it doesn't matter where I leave the trim contol as it only gives a momentary pulse.

There is another type of rotary encoder called a Knitter switch  (not sure if I got this right) which is purely mechanical that gives two distinct switched outputs but again you would end up with a key repeat on a bashed keyboard it would work on a Hagstrom unit or a Plasma unit. Check out the following link for Leo Lecarv's site -- really good stuff.
cheers
chuck

[url][/http://www.betainnovations.com/]
     

[oldhorse]

Hi chuckcrc
  Thank you for your thought.
       Rich

[chuckcrc]

Hi all
I found the link for the rotary encoder from the"Knitter Switch"company.

They call this a rotary pulse switch and it gives a switch closure when you turn it clockwise between two terminals and a switch closure on a different set of terminals when you turn it the other way. I think up to 20 pulses per 360deg turn.

This would be perfect to interface into any type of usb Plasma or  Hagstrom unit without the need for a lot of electronics. These switches would wire direct as these control devices only respond to a change of state.
If you wanted to connect these to a bashed keyboard then you would have to deal with the "key repeat" problem.
This could be dealt with by using a capacitor operated relay which would only give a momentary pulse.
Anyhow check it out, I don't know the costs etc
cheers
chuck
[url][/http://www.knitter-switch.com/]

[chuckcrc]

Hi All
I've had some feedback on those Knitter rotary switches I made reference to and they aren't all that suited to the simpit use, and you have to buy a minimum order of a 100 units.
I've had a response to the author of the rotary encoder cct I use and I can post it here.
[img]http://www.simviation.com/yabbuploads/decoder
.jpg[/img]  

Note: this cct is shown using Optocouplers to interface into  a Hagstrom unit, this would also work into Betainnovations Plasma unit as well.
For a bashed keyboard you would need addittional ccts to avoid the dreaded "key repeat" problem. I have solved this but I don't have a scanner so I would need some freeware easy cad type program to draw up the cct if anyone can help.
cheers
chuckcrc  

[chuckcrc]

Hi All
I've had some feedback on those Knitter rotary switches I made reference to and they aren't all that suited to the simpit use, and you have to buy a minimum order of a 100 units.
I've had a response to the author of the rotary encoder cct I use and I can post it here.
 

Note: this cct is shown using Optocouplers to interface into  a Hagstrom unit, this would also work into Betainnovations Plasma unit as well.
For a bashed keyboard you would need addittional ccts to avoid the dreaded "key repeat" problem. I have solved this but I don't have a scanner so I would need some freeware easy cad type program to draw up the cct if anyone can help.
cheers
chuckcrc  

[Cammo]

Chuck;

What was the feedback you got re: kittner switches? I just ordered 4 ($44 total) from mouser that are similar but made by ALPS for use on my just ordered Plasma V2. I thought I had found nirvana with these!

http://www.mouser.com/index.cfm?&handler=data.listcategory&D=*SRBM1L*&terms=SRBM1L&Ntt=*SRBM1L*&Dk=1&Ns=MfgrPartNumber%7c%7cSField&N=0&crc=true

[chuckcrc]

Hi Scorch
the feedback I got about the knitter switches were that they were-

Continuously
Rotating
And
Pulsing