Newbie....another

[Guest]

Just about to start building a generic 2 jet cockpit (Sept) using mostly GoFlight stuff. However I have one question (2 questions at the moment.1 I have bought 3 15" monitors on Ebay for the flight displays (I already have a projector for the scenery) do they have to be SVGA or are VGA ones ok?2 I am currently using the PFC 2 jet throttle quad. while wating for the release of the GF one. Is there a way of disabling the PFC landing gear knob, at the moment it is overiding my GF landing gear?3 Did isay 2?I have never managed to get the PFC throts to balance throughout their full travel despite FSUIPC and PFC software, any ideas?Thanxfor any replies.flyerian

[Guest LeoL]

>3 Did isay 2?>I have never managed to get the PFC throts to balance>throughout their full travel despite FSUIPC and PFC software,>any ideas?I had thought of a software solution to the problem you describe, but it involves writing a custom device driver to intercept the throttle values, manipulate them based on calibration values and then inject these into the default windows game controller driver. Sorry, but as of this writing, I don't know of any utility out there that does this as freeware.An alternate solution I'm looking into is replacing pots with something much MUCH more accurate.You may or may not be aware that linearity of pots is typically in the +/- 10% range. This, of course accounts for the discrepancy you've experienced when putting both levers at the same spot and the throttles don't match. The options I've researched are:1) ACE encoders at less than 1% linearity. You can find these at about $20/ea.2) Hall Effect sensors from 2% to 0.5% linearity ($40/ea)3) Linear transducers at less than 0.5% linearity ($150+/ea)4) Pressure or Force transducers at less than 0.1% linearity ($600+/ea). Honeywell makes these for use in...you guessed it, Aircraft!As you can see, the cost also increases exponentially wrt linearity! Non of these can be connected directly to a game port or USB joystick and require special circuitry to use them, which I'm currently working on.Well, if anybody has found a better / easier / cheaper way...I'm all eyes! :-coolCheers,-Leo

[Guest MikePowell]

Hi Leo,I would think that a multi-turn wire-wound pot with a modest amount of calibration circuitry would hit a pretty nice cost/performance point. Linearity is pretty good simply by the nature of its construction. Calibration should only need to handle offset and scale. The mechanical linkage between pot and throttle would need to take advantage of the multi-turn nature of the pot to avoid be eaten by the turn-to-turn resistance staircasing.Don't have the spec sheets in front of me, so I'm shooting from the hip. (And prepared to be shot down) Still, seems like it would offer a real improvement over current game controller linearity.BTW, your GammaRay project looks very interesting. Where/how did you get started with USB?Mikewww.mikesflightdeck.com

[Guest Smokintodd]

I'm not sure I quite understand this statement in terms of the status quo... "You may or may not be aware that linearity of pots is typically in the +/- 10% range. This, of course accounts for the discrepancy you've experienced when putting both levers at the same spot and the throttles don't match."I thought this is what most builders were using. I'm about a week away from a 'proof of concept, rev. 2.0' and I thought most builders were using standard 100 Ohm (linear)pots. This is what I've based my throttles on and I hope that I don't run into this.If I do, is there a work-around (something I can plan for so that I can incorporate it now before I go final with my design)?Smokintodd out.Operating out of CYXU

[Guest LeoL]

Oh yeah, totally forgot about multi-turn ones. Just had a look at a catalog and they sell some for about the same price as the ACE rotaries and they claim they have less than 0.25% independent linearity, but they still suffer from +/- 5% tolerance on total ohmage. In the end, you might still end up with two of these pots up to 10% difference between them.However, like you said, to take advantage of the linearity, one has to use ALL 10 turns of it and that could complicate matters with multi-gear setups. Not impossible to do...Personally, I'm simply fed up with POTs. It's gonna be ACEs for my throttles and a pair of Hall sensors for my joystick. I must confess that I plan to use pots for rudder pedals.>Where/how did you get started with USB?I like to think I'm STILL getting started with USB. I've only just scratched the surface. I got interested in it way back when it was still just a buzzword. -Leo

[Guest LeoL]

I can't speak for everyone but I think most people just rip out the guts from digital USB joysticks OR simply put up with the differences in pots.So it's entirely up to you as to how much difference between the throttles you're willing to tolerate. I know someone who bought a bunch of pots and tested them all to try and find a pair that matched. You might get lucky and find a pair that comes to within 5% diff or even less.BTW - its 100K (100 000 Ohms) and not "100 Ohm". Might have been a typo on your part, but I'm just making sure you put down the correct value on your shopping list. ;)-Leo

[Guest MikePowell]

It will be good to see some new approaches applied to controls.Mikewww.mikesflightdeck.com

[Guest LeoL]

Mike, I hope I didn't come across like I was shooting down your idea. I was just trying to convince myself that the $150+ dollars I'm going to spend to replace all my pots will be worth it. :-lolCome to think of it, sliding pots might have a better tolerance since the carbon film is a strip. Might provide better linearity this way. Could be something to look into for those making throttles.Cheers,-Leo

[Guest MikePowell]

Not at all, Leo. It's good to see different approaches and clever solutions.Mikewww.mikesflightdeck.com