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Concentric Shaft Rotary for radio tuning..?

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Yeah, I know COLE makes them. And I was told they cost $50 a piece if you can find someone who sells for individual hobbyists.So I was going for two separate radio tuning knobs, since my cockpit idea is more about "avoiding mouse and keyboard while flying" than looking exact replica of some real plane. So it was okay and it *really rocks* when you tune your radios and vor etc with rotary knobs..Then I talked with a friend and we pondered how many times real aircraft parts are very expensive and if you sometimes get a nice practical idea you can save a lot of money for simpit building. Then it struck us: what if you took an ordinary rotary switch (fsbus can use those as "rotary encoders") and somehow made a hole in the shaft and put another one behind it, then used two knobs.So we thought it might perhaps work and would be good to give the idea some additional thought. I went to a component shop today to pick up some stuff for the FSBUS led card, and I saw these knobs there. "Mmm.. now *if* we could realize that concentric rotary idea, *those* would be the knobs to use..." - I decided to get a set just as food for thought and so I could play with them and think about the idea. The actual construction works pretty amazingly well, here's how I did it:Get thin 6mm (the switch shaft is 6mm) aluminium or such pipe. The "wall" should be 1mm so that the hole inside is 4mm.Get 4mm metal rod. Put the 4mm rod inside the tube. Put the knobs in place. Play with the idea and drool at the cool knobs :-)http://tigert.gimp.org/vatsim/cockpit-stuff/knobs3.jpghttp://tigert.gimp.org/vatsim/cockpit-stuff/knobs4.jpgThen open the switch and replace the shaft with a equal length of the metal tube, superglue in place. You need to drill away the plastic shaft so that instead of the shaft there is a 6mm hole. Push the metal tube in there and glue in place. Assemble the switch, and drill the "back plate" hole through the metal tupe with a 4mm drill bit. This is where we stick the 4mm wire through.http://tigert.gimp.org/vatsim/cockpit-stuff/knobs7.jpgCut the other switch's shaft shorter and drill a 4mm hole a bit in to the shaft, as well centered as you can. Put the switches close to each other and tie them together somehow. I used U-shaped metal and a nylon strap, but something else might work better, this is just a proto.http://tigert.gimp.org/vatsim/cockpit-stuff/knobs6.jpghttp://tigert.gimp.org/vatsim/cockpit-stuff/knobs8.jpgI think it was well worth the effort. It feels very solid and works pretty well. Needs some thought so it doesnt look so ugly though, but the basic idea works well. The pics suck though, sorry about that :)Tuomas

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Guest dirkan

Hi Tuomas,brilliant idea. I have just another tip. If you shorten the spring inside that kind of rotary switches (approx. 1-2mm), it feels a lot smoother. But be careful not loosing the ball.Dirkwww.fsbus.de

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Hi Tuomas, AWESOME!.... I could use it for my radio stack, unfortunately, I have maxed up EPIC limit of using rotary encoder circuits (8 encoders total). Instead of that, I use rotary encoder with push buttons to active 3 digits before dot, and 2 digit after dot for Nav/Com radios.. Also 4 digits in turn to activaete Transponder. Anyway, How many hour did you spend on doing this? Again this is AWESOME!

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>Hi Tuomas, >> AWESOME!.... I could use it for my radio stack, >unfortunately, I have maxed up EPIC limit of using rotary >encoder circuits (8 encoders total). Instead of that, I use >rotary encoder with push buttons to active 3 digits before >dot, and 2 digit after dot for Nav/Com radios.. Also 4 >digits in turn to activaete Transponder. > Anyway, How many hour did you spend on doing this? Again >this is AWESOME! I think this is awesome as well :-) Makes it possible to do more real looking radios that also take less space on the panel. It even makes a GPS panel a pretty interesting possibility... most GPSes have such dual encoder (the GNS 530 and 430 etc)I spent a lot of time pondering and thinking, the actual work of constructing this was maybe a hour, it is *really* easy to do if you have just some tools like a drill press. And mine's not really very sophisticated, more like a crappy one that just holds a normal hand drill. But it's just the "take off the shaft, put in the aluminium tube, glue it, assemble the switch, and drill the other ones' shaft with 4mm bit, and put them together. Very quick to do now that I know it works.There is the spring loaded click thing on the switch, I just had to cut very short pieces of the spring and use those on both sides of the metal tube (it used to go through the shaft) - this seems to work okay, but one needs to experiment with the length of the spring bits, since they need to be very short. They press the small ball bearings against the sides of the switch housing that has detents for the click stops. Again, hard thing to explain but you'll understand if you do your own.I am still thinking how to do the attachment of those two switches together, it helps if the joint can flex slightly if your 4mm hole is not absolutely centered in the other switch. It only needs to keep the other switch from rotating.Anyway, definitely a prototype that works and worth looking into further. Let me know if you get better construction ideas, this is more of a proof of concept. LOVELY thing to use to tune radios though, since it works like the real thing..Tuomas

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Sorry for asking a silly question but I have little electronics knowledge. Dont rotary switches have stops at 30 or 45 degrees? How do you get them to continuously go round to make them work like the radios in the real aircraft. ThanksGaz

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>Sorry for asking a silly question but I have little >electronics knowledge. Dont rotary switches have stops at 30 >or 45 degrees? How do you get them to continuously go round >to make them work like the radios in the real aircraft. Those are 12-step rotary switches. Some of them have a small "stopper" bit inside the switch, one can just cut and file it off to make it rotate freely. These ones have unlimited rotation though. The stops are then at 360/12, that is every 30 degrees.Dirk, yeah, I have shortened the springs, but one makes them easily too short, and then loses the accuracy if it is too smooth rotation. Real radios have pretty strong detents anyway. Now I got to find small enough BCD switches for the instrument panel so they can fit between the glass and the panel. I think FSBUS can do BCD ones?Tuomas

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How did you wire the switch up? I bought 2 grayhill concentric optical rotary encoders with a pushbutton & they have eight wires that come out of the switch. I know vey little about electronics, but Dirk said this would not fit his FSBus because it put out 2 phases.Thanks,Jim

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>unfortunately, I have maxed up EPIC limit of using rotary >encoder circuits If you look in this forum for a message of mine titled "[a href=http://ftp.avsim.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=354&forum=DCForumID42]Final (i hope) solution for rotary encoders![/a]" you'll find how to get rid of additional and costly encoder modules, and any hardware number limitation.With that thing you can use an encoder just like a pair of buttons, thus hooking it up to any key card, like fsbus key module, or epic's one.CiaoClaudio

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>little about electronics, but Dirk said this would not fit >his FSBus because it put out 2 phases. Correct, right now fsbus can't directly handle such encodes.You need some other hardware like the one mentioned by me in another post (went totally unread) on this forum.CiaoClaudio

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Hi Claudio.I read your earlier post & checked out the site. Unfortunately, not being electronically knowledgable,it didn't mean much to me. Would you mind looking at the data sheet for the concentric encoders I got from Grayhill & tell me which interface chip I need & how to hook it up to concentric encoder? Could you also show me how to wire this assembly to Dirk's FSBus?Thank you,Jim

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Nicely done, Tuomas. Very impressive.Peter http://bfu.avsim.net/sigpics/PeterR.gifBFU Forums Moderator[table border=2 cellpadding=0 cellspacing=1][tr][td][table border=0 cellpadding=8 cellspacing=0][tr][td bgcolor=#540000]http://bfu.avsim.net/sigpics/logo75t.gif[/td][td align="center" bgcolor=#FFFFF6]Bush Flying Unlimited"At home in the wild"Looking for adventure? Come join us! * [link:bfu.avsim.net|Web Site] * [link:www.cafepress.com/bfu,bfu2,bfu3,bfu4|BFU Store] * [link:bfu.avsim.net/join.htm]Join!][/td][/tr][/table][/td][/tr][/table

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