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Building some flight control hardware for PC

Started by June 16, 2008 02:35 PM
9 comments, last by akluzz 16 years, 5 months ago
A friend badgered me into buying IL-2 Sturmovik on steam today, and like the fool I am I figured that this combat flight simulator could be played like any other I've touched, using a joystick with X-Y axis for roll and pitch, and then the less than pleasant work around of using keys for the Z axis yaw. I was wrong, the best I have a choice of using keys, which produce a +/- 100% deflection on the rudder, which results you you trying to shoot something with a rifle through a scope, while your buddy stands besides you and randomly pushes on your shoulder. So I think I would much rather have pedals and maybe even a proper throttle control. I honestly would rather build something myself with a metal frame, and maybe even a nicely carved wooden covering for flavor, but I'm really not sure just how to go about this. I can find all sorts of information on using the Gameport to do something like this, but my system only has USB, Parallel, and a serial port. I'm not new to wiring up electronics, only wiring for the PC is new to me. My goal is to be able to have 2 to 4 pots, and then a handfull of buttons/switches, ideally with room to maybe expand the controller, adding extra pots or buttons as I find a use for them. At minimum I need, 1 linear pot for for the pedals, 1 for throttle. 2 buttons for up/down Prop Pitch, 2 for fuel mix, and then maybe upwards of 4 more for the basics. Ideally I will want upto 7 pots, and say, 8-10 buttons. So, what is likely the easiest route to research for something like this? Can the basic option be done for less than $50 CAD for the control hardware? (case and actual stuff I mount things I can do for 'free' basically. If time was really money, I would be one of the richest men in the world right now.)
Old Username: Talroth
If your signature on a web forum takes up more space than your average post, then you are doing things wrong.
If a little creating wiring you can do all sort of things through an old keyboard. All keyboards use a matrix to determine what key is pressed. All you have to do is wire up the .matrix to your buttons and tada, one plane simulator.

If you want more info on this just send me a pm.

theTroll
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True, but that might not be as easy to get the smooth flow that potentiometers would, and I'm not sure how easy it would be to rig as many controls as I want on that. I can see a way that I can use switches to get a smooth control transition that won't be a pain to wire, or highly prone to failure/hard repairs compared to potentiometers.
Old Username: Talroth
If your signature on a web forum takes up more space than your average post, then you are doing things wrong.
As long as you watch what you are doing and put the diodes in the right places, you can get 104 switches on a basic keyboard.

theTroll
Your going to have a HELL of a time building a device driver for a USB device, and your going to need a programmable rom, the device that writes to it, boards, etc. Overall, the cost will be a few houndered just for that, and then all the time spent... My advice is buy a card that supports the COM port, those are MUCH easier to program and build devices for. Seriously.
Well, I already have access to the equipment to flash FPGAs at school, so any investment in that direction is simply the cost of the chip itself. Waiting to hear back from the lab admin on just what my options are for chips to use with their equipment.

Besides, if I wanted 'easy' I would head down to The Source and pick up the one I saw when I was seeing if they had any pots in stock. (They did, but only one, and weren't getting more again anytime in the foreseeable future.)
Old Username: Talroth
If your signature on a web forum takes up more space than your average post, then you are doing things wrong.
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If you're going to be using an FPGA, bear in mind that the packages they are available in generally have a large number of pins and as such you'll need access to decent soldering equipment and be able to produce a decent PCB. Either that or use an FPGA prototyping board which you wire your own hardware up to (in either case you're gonna be spending more that $50 I would have thought, unless you can get a PCB made for free or close to nothing).

Serial is a very simple interface to deal with. You can get it running at 14 kB/s if you want 10 pots, and you use 8-bit samples that's 10 bytes, add another 2 for buttons and that's 12 bytes for a status packet, and you could send slightly more than 1194 of them per second with serial running at the maximum speed which should be plenty. You may get nowhere near this maximum but I would have thought 100 or even 10 per second would work.

Personally I'd forget about the FPGA and just use a simple microcontroller, coupled with an ADC, you can either get a microcontroller with built in ones or a seperate 10-channel ADC. You'll also get an built in UART in the microcontroller to handle the serial. Then your only problem is writing the drivers [grin]. The DDK for windows is available here (There's a newer one but you may need to be an MSDN subscriber to get hold of it, or at least fill in some kind of form). I don't know much about windows drivers so I can't really help you here (Someone's probably done something like this before, search google). It may be simpler to produce something that works over USB that's a generic gamepad rather than writing your own drivers for your serial device (again you can get microcontrollers that have USB support built in that may help you here).
Or you could just use one of these A-PAC1 or this A-PAC2 (has 6 pots but u will need a keyboard interface like the I-PAC as well). I haven't used the analog versions yet but I have used a couple of the normal I-PACs for various uses and have never had a problem, certainly beats trying to wire into an old keyboard, plus you can use pots.
I have been thinking about this and there is another option also, xbox controllers. Each controller will give you 14 buttons and 6 analog (your pots) controls. With two you would have more controls then you would ever need.

theTroll
I would do it like this... i'd buy a 4D joystick which has:
1: xyz stick, which is a stick that you use normally for pitch and roll and can turn left and right for yaw.
2: throttle
3: a lot of buttons.
Alternatively, if on tighter budget, i'd buy:
2 cheap joysticks, thats about 10 .. 15 euro for xy and throttle, 20..30 euro total. Cannibalize sensors off one joystick to make pedals or turnable handle.

Alternatively, on really tight budget:
Classic analog joystick card or adaptor (has 4 or even 8 analog inputs) . Like this, or general ADC (analog to digital converter), plus potentiometers.
Classic pc joystick works like this. On every cycle, capacitor is charged, and discharges through the potentiometer. The discharge time for certain voltage is measured. So joystick itself only needs potentiometer, and whole thing is extremely simple; you can even make that yourself for parallel port very easily, if you got parallel port of course.
I did make my own joystick in old days when i had 286 20mhz computer. It was epic, unfortunately no photos of the epicness survived :(

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