SIM interface cable on Aero-Hawk remote control

[Lonberg]

Hi RC helicopter freaks,

Have just acquired a Smartech Aero-Hawk as my first RC helicopter ever, and am trying to get the simulator SIM cable work with FMS on my PC, without luck. I am running Windows XP, and the cable has a plug in one end for the RC and a kind of double plug in the other end with 9 pin and 25 pin female plugs. Guess the 9 pin is for serial interface to the the computer, but have no idea about the 25 pin ? When opening the plug, it seems to contain an 8-bit microprocessor.

Anybody having suggestions about why it doesn't work?

[Malc C]

Could be 101 reasons:

TX not sending a recognised PPM signal, PC not receiving correct serial signals, The device requiring a 3rd party driver as XP won't allow direct access ?

I'm sure that this issue has been discussed before.. try the search function and see what comes up

[Lonberg]

Thanks Malc C for your swift answer. You are right, there can be many reasons, however, have already spend many hours of searching and surfing, trying to at least find a cable like mine.
What I hoped was, that somebody have the same kind of interface, and could give an explanation. I have a suspicion, that the 25 pin should be used in some way for power to the microprocessor in the plug, as the 9 pin serial connection is not able to give sufficient power.

The manual for the Smartech Aero-Hawk is very bad, and gives no explanations at all about the simulator interface.

[slipstick]

It's more likely that the 9-pin and 25-pin plugs are just alternative connections. 25-pin serial ports used to be standard a few years ago though I haven't seen one for a while. The power capability will be the same whether it's a 9-pin or a 25-pin plug.

Have you tried searching/asking on FMS's own forum ?http://n.ethz.ch/student/mmoeller/fms/forum/

Steve

[Lonberg]

Hmm, must admit that I was not aware of that forum, thanks a lot, will dig down through it.

[Malc C]

Steve, you beat me to it.. I agree that the 25 way connector is probably parallel wired to the 9 way just in case your old PC only has a old 25 way connector.

Longburg, by the sounds of it the cable is based on a PIC serial design (the small IC is probably a 12C508/509 or variant). This will take the PPM signal and convert it in to a protocol that the PC can then use to communicate with the software. These devices are powered from the serial port, and on some computers (laptops in particular) the serial port can not provide the curren or voltages needed to generate the 5+ that these PICs use.

Some tests you can do to rule out some of the points I mentioned include downloading one of the soundcard based oscilloscopes and test the port on the back of the transmitter for a true PPM signal.

I use "logic analyser 8" and have attached an example from my JR 3810 tranny. If you get a similar trace (obvioulsy my TX has 8 channels plus the sync pulse, yours should have 4 plus the sync pulse)

http://www.micro-heli.co.uk/scope

To be honest, IMO your best bet would be to bin the cable and treat yourself to a USB joystick interface. Cost about £30 but will save you from pulling your hair out :)