[vcf-midatlantic] What's wrong with my program experiment?

Jonathan Gevaryahu jgevaryahu at gmail.com
Thu Apr 6 00:16:36 EDT 2017

We're dealing with probably worn analog potentiometers; 130 is close 
enough to 127 that it shouldn't matter.
Check how much of a dead zone you have first by wiggling the stick 
around lightly and seeing what the minimum and max for x and y are 
without engaging the springs at all. There's not much you can do to fix 
this dead zone, if present, short of finding another joystick, its 
equivalent to machinist equipment backlash.
The problematic direction is Y, so adjust the trimmer until it is near 
127 when centered in the 'middle' of the dead zone, and then pull it to 
255,255 corner and adjust slightly until it just barely hits 255,255. 
That's pretty much the best you can do, short of replacing the Y 
potentiometer with one which acts more linear.

On 4/5/2017 6:26 PM, Evan Koblentz via vcf-midatlantic wrote:
> Disregard my entire post from earlier today. :)  Here's a smarter post:
> I'm using the Apple joystick A2M2002.
> Ran this test program:
> 10 X=PDL(0):Y=PDL(1)
> 20 PRINT X,Y
> 30 GOTO 10
> The four corners report correctly (0,0; 0,255; 255,0; 255,255) but 
> when the joystick centers it shows 130,89. If I adjust the trim knobs 
> then the corners would be wrong.
> How do I fix this?

Jonathan Gevaryahu
jgevaryahu at gmail.com
jgevaryahu at hotmail.com

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