Hi Sokol,
>> Thanks for the tips. <<
You're welcome!
>> Beyond the issue of the potentiometer course degrees (60), there is the fact that the axis of potentiometer is part of the gimbal (without potentiometer in place the gimbal disassembles)... <<
That's can be a problem if the stick is heavily sprung, but the CH sticks would probably be okay. If the springs are very stiff, it can create problems eventually though. The pots wear out and fail very quickly if the springs are too heavy. I wouldn't think the CH sticks are sprung heavily enough to be any trouble though.
>> So, to use a commercial potentiometer need one with:
>> - 60 degrees of rotation <<
It's about that for the active area, but it depends on the stick. The pot will turn 270 (some pots will go to 300) degrees rotation even with the 60 degree pot range. It's the stick case itself blocking the stick that limits the stick travel. It has nothing to do with the pot at all, really. It's just that brown piece with the terminals on it. If you look at the ink pattern you can usually see the active area, it's directly across from the pot terminals. You have trouble getting exact alignment, but it's not that critical really. Calibration pins the end points and center point for each axis, the resistance probably wanders back and forth across the line that tracked the ideal position, but it's close enough for most things.
Ideally, the active range should just cover the angle that the stick swings through going from full left to full right or full forward to full back. Not necessarily 60 degrees, it depends on that angle more than anything. You probably can't match things completely.
>> - axis with the same diameter and length, bushing instead thread same D recess on axis. Small chance to find one that fulfill these requirements... <<
Actually those are standard options, I think most of the pot manufacturers offer similar things. The biggest cost, assuming they'll still make them, is usually a minimum quantity and a setup charge.
It is, or at least was originally, a CTS 295 series pot IIRC. You should be able to generate a part number for it from the info in the PDF, then you'd need to talk to CTS and see if they could still be had. If so, you'd be set. But, really, they almost never fail. They're much more likely to be physically damaged somehow than actually worn. It wears symmetric around center too, so if it were to wear enough that it was noticeable, it would only be a slightly higher sensitivity near center, not really that much of a problem. The Gain setting in the CM would counter it.
>> This model is similar
http://www.ctscorp.com/components/potentiometers.htm <<
That page is the place to go, pick up the PDF file for the 295s and you can sort a lot of it out. The PDF explains how to generate the part number, I don't see anything that matters that isn't on that list. They all rotate 300 degrees (not 270), the "active area" is under It's a series 295. You can download a PDF data sheet for it from that same page at ctscorp. They explain in that file how the model number defines the pot, the shaft length, type, whether the shaft is flatted or knurled, etc. The say the angle of rotation is 300 degrees for all 295s, that's total shaft rotation, and that the electrical rotation (the active area) has a code that tells what the electrical rotation will be. If you can measure things accurately enough, you can probably figure what the stock options were and pretty much duplicate what the stick is now.
It's the electrical rotation that important. All the 295s turn 300 degrees, but it could only be active for as little as 40 degrees. A 60 degree is one of the options in the part number. The active area, the "60 degrees" is shown under "Taper and Electrical Effective Angle, and 60 degrees is one of those listed.
Anyway, someone gave me a number for the Omron switches that are used for most everything else. If the pots could be made available, it would basically cover the basic parts you need to maintain the things. For low volume, an eBay used stick is probably the best bet, and a "Hangar Queen" is useful if you snap a Hat Switch or the cat swallows the ProThrottle.
But the code suggest that are 270 ones. <<
This is one of those with 300 degrees according to the data sheet (so nice to have a data sheet), and the 60 degrees should work fine. The only exception would be the Quad, which uses PC Terminals and solders into the board. They're going to be hard to swap.
>> Well, I am thinking in try a different alternative:
Won't work...Voltage is Vcc and Vss...1/3rd turn will give you less but you can't adjust for it unless you set up a reference supply.
Are 13 bits sensor build for use in joystick/rudder... allow 8192 points of resolution in 180 degrees, work on 5v like a potentiometer (+5v, signal, gnd). <<
I couldn't really see how you were going to move the pots, and the magnet you mention suggests maybe it uses Hall sensors. Anyway, that's all a little unclear, but you keep talking in bits and the system is looking for a voltage. If the little cards have ADCs on them. There's usually a REF+ and REF- terminal that lets you set what the ADC needs to see for max and min values. Mostly they're just tied to the +5 and GND terminal.
Other then that, they'd work if you were going to use the stick just going through Windows. but the CM still requires that you get a real CH board somehow, one that has enough axes and buttons to meet the requirements of whatever controller you were trying to emulate. If you do go to the Control Manager, it's all 8-bit data, 13 bits wouldn't really help. Easy enough to convert if you need to, just a matter of throwing low bits away until it's 8 bits wide. Just ignore them entirely. Or, I suppose you could scale it down, I don't think it would matter a lot, though.
The sensor (the pot in this case) really has nothing to do with the resolution. The pots or Hall sensors have "infinite" resolution. The overall resolution depends only on the A/D converter that picks up the data. The CM itself uses 8-bit data for everything.
>> Theoretically, if turned only 60 degrees (~33%) - case of joystick - this sensor give m points of resolution. Similar to are get in MFG Crosswind pedal.
Since the Fighterstick USB controller are 8 bits (256 point) I will got 256 points with 60 degrees movement after calibration using this sensor, this thought is correct? <<
The thought is correct, or so it seems, but you can't use more than the 0..255 range so there's really not much point in dealing with a finer resolution (unless you're just going to run it through Windows, then I suppose it can be whatever you need). If you want to program it with the CM, 8 bits is the most you can use.
Anyway, maybe that will be some help. For a one-time repair you're still probably ahead buying a used unit, giving the isopropyl treatment to the pots, and do it that way. You're not likely to have to do it again for several years.
Best regards,
- Bob
The StickWorks
http://www.stickworks.com