Simviation Forum - A 20 Button USB Digital Interface

Sep 10^th, 2007 at 6:45pm

Mr Steve Offline
Lieutenant Colonel
I Fly Sim!

Posts: 6

A few weeks back, I came across an Adapter that allows you to connect up to 20 switches to the USB on your computer. So, I bough two of them and I must say, I think they are pretty good for the money. i was also surprised that i did not add switches using an x/y matrix, like other adapters but rather this board has wires running out of it directly from the ic. I think this arrangement makes wiring a lot easier.

It was easy to wire up a few push button switches to the board and I used FSUIPC to program the switches to work my FS2004 - GPS display. It turned out really good.

I'm now working on adding another 10 switches and have them programmed as an autopilot.
What I really like about the board is that all you need to connect the switches to the board is a 32 pin ribbon cable, like the ones you find in the floppy disk drive inside a computer. I just soldered every 2 wires from the ribbon cable to a push button. You don't even have to solder the switches to the board. I think that saves money in the long run if you very decide to redesign the switch panel. just remove the cables from the board and solder another bunch of switches.

The boards come from a placed called Desktop Aviator in the US. The board costs only $29.00 plus shipping.

http://www.desktopaviator.com/Products/Model_2040/index.htm

For anybody who wants to design and build their own cockpit, i think this board is worth looking into.

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Reply #1 - Sep 10^th, 2007 at 9:56pm

JBaymore Offline
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Thanks for sharing the listing.

One reminder here for the newer cockpit builder looking at this item:

This interface is mainly for normally open momentary type push button switches. Sort of like glorified computer keyboard keys. Which is certainly FINE for some simpit uses. This would be great for something like a panel that allows you to select the responses to the default ATC and to pop open windows or something like that.

If you want to use standard toggle switches (NOT the mis-leading "spring return" toggle switches mentioned in some of the writing), then you need to construct a circult using an opto-isolator IC for EVERY regular (single pole single throw or double throw) toggle switch that yopu want to install. That woprk gets a tad more complicated and expensive to do.

So if all you want is momentary buttons for your particular interface....this is another rather cheap way to do the trick.

best,

.......................john

Intel i7 960 quad 3.2G LGA 1366, Asus P6X58D Premium, 750W Corsair, 6 gig 1600 DDR3, Spinpoint 1TB 7200 HD, Caviar 500G 7200 HD, GTX275 1280M, Logitec Z640, Win7 Pro 64b, CH Products yoke, pedals + throttle quad, simpit

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Reply #2 - Sep 11^th, 2007 at 10:31am

npbosch Offline
Colonel
I love YaBB 1G - SP1!

Posts: 27

Hi John,

Till recently I thought the same. Only momentary switches could be connected to these kind of usb joystick devices.

I recently adviced someone on a German forum on this topic. But he insisted on using real toggle switches (on-off). He connected them via his usb hacked joystick and used fsuipc. It has an inbuild setting for this.

when button pushed ----> light on

when button released ----> light off

And he told us that it worked. So, if you use fsuipc , you could also use normal switches, which give you a more better feeling than these momentary types.

regards

Norbert

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Reply #3 - Sep 11^th, 2007 at 11:10am

JBaymore Offline
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Norbert,

Hum.... that sounds a tiny bit suspect as to actual functionality to me.

The IC installed on the USB device is configured to act pretty much like a keyboard. When a key is pressed, it sends a continuous string of pulses of that keycode, re-sent at a rate determined by the repeat rate.

So now let's hook up 10 to 20 toggle stitches and give them functions that are to remain "on" for long periods of a flight, like maybe fuel valves, fuel pumps and so on. So I take switch # one and flip it on to start my fuel pump. The USB card starts sending a string of "Keypress 1" scan codes to the computer via the USB buss. The computer then processes these via FSUIPC and that software strips off any but the first keypress to control the fuel pump in the sim to toggle it to the "on" state. Great... the sim is functioning correctly.

However, on the hardware side of things, nothing is telling that USB controller IC to stop sending the keypress for that switch. So it just keeps on sending, and sending, and sending. The computer's CPU is looking at that every few cycles and saying, "Hey FSUIPC you want this data?". FSUIPC says, "Nah"...and the CPU ignores it for a few more cycles and then askes again. And again. And again.

Now I ALSO flip on toggle switchs #2 through 20 all of them up to switch 20. Now the USB controller is continuallly sending about 20 different continuous keypresses onto the USB buss. FSUIPC takes care of the sim.... but nothing is stopping those keysends on the buss.

It would seem to me that all that continual "traffic to nowhere" on the buss could lead to issues with speed of transmission of OTHER components sharing the USB buss for necessary communications. A lot of us run a LOT of USB type components. And it seems to me that the monitoring of those data packets by the CPU is stealing valuable cycles that could be used for other tasks.

So while it may "work"... is it really the way to go unless there are NO other choices?

What do you think about this "logic" (if that is actually what it is Wink

)?

best,

.....................john

Intel i7 960 quad 3.2G LGA 1366, Asus P6X58D Premium, 750W Corsair, 6 gig 1600 DDR3, Spinpoint 1TB 7200 HD, Caviar 500G 7200 HD, GTX275 1280M, Logitec Z640, Win7 Pro 64b, CH Products yoke, pedals + throttle quad, simpit

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Reply #4 - Sep 11^th, 2007 at 4:48pm

npbosch Offline
Colonel
I love YaBB 1G - SP1!

Posts: 27

John,

I could not better explain this as you did. Thats exactly why I thought it could not work. Besides that, these devices use sometimes a kind of matrix layout, that could cause further problems.

Best would be to use a special IO card like the ones we all know. Or a simple hagstromencoder, they can accept real switches.
But nonetheles that German chap proved that it worked.

Why did Pete Dowson build that in FSUIPC? For the landing lights there is a LANDING_LIGHT_TOGLE, a LANDING_LIGHT_ON and LANDING_LIGHT_OFF. The first one is for a momentary button. But for what are the 2 latter ones meant?

Real IO cards use their own software, but perhaps this is why Pete build that into fsuipc?

Regards

Norbert

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