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Unread 17-12-2008, 12:26
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Re: CH Flight Stick Compatibility with 2009 System?

Quote:
Originally Posted by Kingofl337 View Post
I think the biggest complaint with the "old" stuff the joysticks don't auto center. But, either way I have a solution for everyone who wants to have a genuine USB HID CH Flightstick Build a HID USB Device
Auto-centering may be overrated. Especially if you're not expecting it. See here.

As to making an adapter for analog joysticks, remember that the pots in the joysticks don't work as voltage dividers, they work as variable resistances. Directly connecting the X-axis pin to an analog input isn't likely to work well. To get the pots to work linearly, you'll need to build a constant current power supply to draw approximately 50 micro-amps through the pot from 5V. You should be able to make one with a few resistors and transistors, but the point is that getting true linear response out of the joystick isn't going to be simple.

Alternatively, you can create a sort of voltage divider out of it by jumping the joystick signal to ground through a resistor. The problem here is that you're not going to get a perfectly linear response from the joystick. I've attached a picture of what it'd look like with different resistor values. It gets more linear with higher resistance, but you end up with more noise and a reduced overall range you're reading from. With the 500K, you're reading from 4.166V to 5V. With 100K, it's 2.5V to 5V. This obviously reduces your resolution. The analog inputs are 10-bit, so a 100K resistor would knock you down to 9-bit resolution. A 200K resistor would put you a little over 8-bit resolution. Practically speaking, it'd make the most sense to bust open the Flightstick and see if you can re-wire the pots as voltage dividers. If you can't, then I'd recommend grabbing a copy of The Art of Electronics, or weaning yourself off the Flightsticks as best you can. Given the plethora of joysticks out there, I find it hard to believe you can't find one you like.
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