Can FSUIPC support generic potentiometer input?

[MichaelC]

Hi Peter,

I have read all the doc I can find, but am unsure about the ability of FSUPIC to interpret potentiometer input. As far as I can see - it handles the mapping of buttons to keys and 'programming' with key combinations.

I have seen a number of messages in the forums about CH and other commercially produced throttle quadrants - but nothing about generic potentiometer output.

A friend has built a cockpit for FS2004, including 2x throttles, 2x prop rpm, 2x mixture as well as a left - right and 'up - down' yoke and rudder pedals. All these work potentiometers - but he had no idea while building it how to get FS2004 to read and interpret these variable output devices. Can FSUIPC help here or are we barking up the wrong tree?

Looking forward to your response.

I hope that this is not too much of an idiot question.

Thanks and Regards,

Michael.

[Frank.O]

Michael,

you do not need FSUIPC to make you setup work in FS in the first place (though I would strongly recommend getting it). FSUIPC as well as FS can only work with input devices that are seen by windows. In simple words: you'll have to make all your potentiometers to look like one or more joysticks. The most simple way to do this is to get a few simple USB joysticks, disassemble them, use only the electric circuit and the cable and connect your potentiometers and buttons instead if the original ones. Then you can plug them in one by one and calibrate them in Windows gamecontroller. After that FS will see them, you can assign axes and buttons and you can refine the calibration using FSUIPC.

Before I started using PFC equipment I had something like that running and it worked fine.

Regards,

Frank

[Pete Dowson]

All these work potentiometers - but he had no idea while building it how to get FS2004 to read and interpret these variable output devices. Can FSUIPC help here or are we barking up the wrong tree?

FSUIPC isn't a hardware driver program. Frank's answer is correct. The best (most flexible) way for any input device is to get it recognised by Windows.

Potentiometer circuits needs some sort of AtoD (analogue to digital) conversion first in any case. The only way you can directly connect analogue pots to a standard PC is via the old syle Game Port, which has almost disappeared. USB has become the replacement, but building the circuitry for a USB device is beyond anything I know. So if your friend doesn't know either, I think the best you can do is get a USB-to-Game Port adapter and use that. A standard game port supports only 4 axes and 4 buttons, so you'd need two.

Aother alternative is to use a ready-made AtoD system like EPIC or one of the more recent hardware interfacing systems. There seem to be plenty around now --- ask in a cockpit building Forum.

Once you have solved the actual connection problems, then either you have something which looks like a joystick input to Windows, so you can then calibrate in Game Controllers and thence use it in FS and FSUIPC, OR you just have something which a program can read values from, such as via a serial or parallel connection.

In the latter case you could interface to FS via FSUIPC. You'd need to write a program to read the values from your AtoD device and send them to the appropriate parts of FS via the relevant "FSUIPC Offsets". To find out more about this alternative you need the FSUIPC SDK -- http://www.schiratti.com/dowson.

If you use of of the proprietary interface devices (EPIC, FSBus, Phidgets, whatever) you should find that they provide the drivers which do the interfacing to FS/FSUIPC for you. You program them via paramters or internal programs to do just what you want.

Regards,

Pete

[MichaelC]

Frank and Pete,

Thanks very much for the swift and comprehensive response. Frank - I will get my friend to try out your suggestion and see how it goes from there.

I have read about EPIC and other (for me) expensive options and am willing to try some of the simpler - even if more time consuming and possibly initially more frustrating - options in the first instance.

Well - here is where we start into the world of cockpit building .... 'til we chat again,

Regards,

Michael.

[rickalty]

Just an addition to Franks post..... be sure to buy a cheap USB joystick to use... a lot of the better ones "self calibrate" by using a fancy potentiometer for the axes that is actually two pots in one case. When the axis is centered, both pots are open circuit. As you move the stick one way, one of the pots stays open circuit, the other has gradually decreasing resistance.

To use a stick like this in your home made pit you'll need to reuse their pots, as there's otherwise no way to do it.

(I found this out the hard way when the four-axis (twist grip) joystick I bought to strip turned out to use this system)

Richard

[Daniel Delande]

I have used the 3 kinds of joysticks for a home-made pedestal:

- an analogue joystick to USB converter (4 axes, 4 push-buttons and 1 4-way coolie hat). The advantage is that the axes do not require pots (3 wires) but only rheostats (2 wires): the device performs a resistance measurement (range about 0 to 100 kOhms). This makes your life easier, because the levers require to rotate much less than the 270 degrees of a standard pot; using a 1 MOhm pot as a rheostat, you get the 100 kOhms in 27 degrees, and using a 470 kOhm pot, you get the 100 kOhms in 57 degrees. The drawback is that the resolution is very poor: I found 5 bits, i.e. only 32 different digital values. I used one axis for the airbrakes lever, another one for home-made pedals. Note that if you use the coolie hat, you cannot wire the 4 button inputs to switches, but only push-buttons, and that you'll have to wire a few diodes (because the coolie-hat function actually requires you generate a combination of several button presses).

- a low-cost USB joystick (Trust's QZ501 predator, 4 axes, 6 buttons and 1 8-way coolie hat). Same advantage, 1 MOhm pots used as rheostats allow a rotation about 50 degrees. The resolution is 7 bits, i.e. 128 different digital values. I used that for the throttle and prop pitch levers (twin engine prop aircrafts) or the throttle levers (4-engine jets).

- a more expensive USB joystick (Saitek's Cyborg USB, 4 axes, 12 buttons and 1 8-way coolie hat). I found that kind of proprietary pot that you have to use as is (also, I have a spare joystick, in case a pot fails). The rotation angles are not the same for all 4 axes (about 30 to 80 degrees), so they are not so easy to use. But the resolution is 8 bits, i.e. 256 different digital values. I used that for the mixture and flap levers.

Keep in mind that if you need more than 1 joystick, you must use different models (otherwise, FS will only take care of 1 of them).

Should I make a new pedestal, I would probably use another solution that I found recently, see http://www.mindaugas.com: you can get 8 axes and 21 push-buttons through a single USB interface.

Best regards,

Daniel

[Farrokh]

Hi Peter -

I'm using Phidgets (8/8/8) cards to interface the pots on my cockpit - the pots are the original ones (one on each throttle, flaps, elevator) from the 747 shell I'm using, they work fine and the Phidgets software interfaces them with MSFS - however, the FSUIPC options menu/joystic calib window does not reflect the changing values when I move the pots - in effect, I can't use the options in fsuipc like the various response curvers, which are great for fine tuning - Does this mean that if I use Phidgets, these fsuipc goodies will be unavailable? Or have I not switched on something..

Cheers,

Farrokh.

[Pete Dowson]

... the Phidgets software interfaces them with MSFS - however, the FSUIPC options menu/joystic calib window does not reflect the changing values when I move the pots

It sounds like they write directly to the FSUIPC offsets, rather than act like real joysticks or send Axis controls. This is the same as an external autopilot application would do, for instance.

Does this mean that if I use Phidgets, these fsuipc goodies will be unavailable?

Yes, because if this is the case the control software is writing directly to the place where the end result of these goodies end up. In other words they bypass all manipulations and write direct to FS's simulation engine.

Regards,

Pete

[Farrokh]

Hi Peter - now that's a pity - thanks for the quick reply anyway - will check on the phi forum if there's a way to fine tune via their s'ware - or something else -

cheers,

FC