Re: Apple vs. PC Joystick (was Re: Different joystick connectors on II and IIe?)

[mjmahon@aol.com (Michael J. Mahon)]

Linards Ticmanis wrote:

>Mike Pfaiffer wrote:
>
>>     I don't think you can get one any more. OTOH if you are handy with a 
>> soldering iron you can make one. FYI, the internals of the PC joystick 
>> and Apple joystick are compatible. An adapter was made for that device 
>> as well.
>
>Are you sure? I tried to build an adapter and the buttons worked 
>"negatively". I.e. pressing it was considered releasing it by the Apple 
>and vice versa. I suspect the Apple Joysticks have "normally closed" 
>microswitches in the buttons, no?

No.  The difference is pull-down vs. pull-up.

Something to look out for is simultaneously pressing a joystick
button and a keyboard Apple key--the result is a short of +5 to
ground, at least on earlier //e's.

>Not to mention the fact that the timing capacitors in my clone where 
>such high tolerance beasts that even with 25kOhm resistors in line with 
>the joystick variable resistors the whole thing was totally off centered.

Adding a series resistor can never create a centered joystick.  Since
the problem is that IBM pots are 100K and Apple's are 150K, an
additional capacitor needs to be added to increase the RC constant
by 50%.  This will make the IBM joystick "full range" on the Apple.

See Rubywand's FAQ on the modification.

-michael

 Email:  mjmahon@aol.com
 Home page:  http://members.aol.com/MJMahon/