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View Full Version : elevator trim on a custom panel



sewells
03-26-2002, 08:24 PM
Hi all,

I have a custom panel which I'm doing early testing on. It has a elevator trim wheel and currently two other rotational ports using a standard analog joystick to usb converter (radio shack's). My problem is that the flight sim only seems to recognize about 32 unique positions. This makes precise elevator trim difficult and I was hoping for better. Any thoughts help making the elevator trim have more steps, and thus better control, would be appreciated.

I can confirm that only 32 unique positions are used a couple ways. One is with FSUIPC which, as the wheel is rotated, only reports 32 different values. Also, when looking at the elevator trim indicator on the FSD C115 panel, I also only jogs to 32 different settings.

Here is my entry in fs2002.cfg for this set of ports
[JOYSTICK_MAIN {FC330540-40C7-11D6-8001-444553540000}]
AXIS_EVENT_00=AXIS_PROPELLER_SET
AXIS_SCALE_00=64
AXIS_NULL_00=1
AXIS_EVENT_01=AXIS_ELEV_TRIM_SET
AXIS_SCALE_01=-127
AXIS_NULL_01=1
AXIS_EVENT_06=AXIS_THROTTLE_SET
AXIS_SCALE_06=-127
AXIS_NULL_06=1

Thanks all!

http://www.flightsim.com/dcforum/User_files/3c9384874916530e.jpg

Indo_FS
03-27-2002, 04:29 AM
I think the problem is in the 'radio-shack-joystick-to-usb' because the analog-to-digital converter has only 32 step converter....

The only way out is to use analog-interface witc FSUIPC, yu can use EPIC card or costum (below $20) circuit..

I have a circuit that interface 8 analog input (pot-frienly) via serial-port, and simple visual-basic will do the job.., you can event interface it for flaps and auto-brake switches.
But I don't have the vb code yet, just the circuit and hex code for the PIC-chip, maybe in my next project. email me if you interested..

sewells
03-27-2002, 10:51 AM
Yea, it appears as though the cypress chip implementation analog->usb converter is 5 bit. I guess I shouldn't complain that a 4 channel, 5 bit, 6ft cable, $15 solution isn't good enough. I suspect that getting much more than 7 bits isn't possible anyways given noise and cable length issues. Obviously the smarter answer is to put the analog->usb conversion right at the pannel and then route 6ft of usb cable instead. I guess that "a ha" happened to the joystick designers about in the mid 90s when the first digital joysticks became available.

Keeping to 5 bits is also smart decision in that there isn't any jitter which keeps the outside view from appearing to vibrate.

I wonder if there would be any money in doing a version of the cypress usb chip that would deal with optical encoders (like my $20 microsoft joystick) rather than analog pots. I don't know much about the optical cousins to the pot other than they certainly are more precise. If anyone wants to drop me a few $k, i'd make one available :)

http://www.flightsim.com/dcforum/User_files/3c9384874916530e.jpg