[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Wireless joystick for the Apple II?



larwe wrote:
On Sep 22, 10:42 pm, Steven <diespamm...@killspammers.com> wrote:

If there is a way to covert the port to a serial, there is a Serial to
USB, then any wireless USB mouse with a receiver could be used.

Well, no it couldn't, because (leaving aside the fact that a serial-
USB converter will be DEVICE-side, not HOST-side USB, therefore will
not connect to a USB mouse's receiver - this is an instant show
stopper), a mouse gives relative position data, not absolute.

The simplest path I can see is to take a proportional RC system and
hack the receiver outputs to convert the PWM (servo drive signal) to a
simple analog voltage. It MIGHT be as simple a matter as a low-pass
filter and a voltage divider, but I suspect not.

Actually, it needn't be much more complicated than that.

The servo PWM pulses vary from about 1 ms. to about 2 ms., so you'd need
measure the duration of each pulse (just filtering would probably slow
down response too much) and convert that timing variation into a
resistance variation of a few ohms to about 150kOhms (an FET would be
fine for that, or you could just do a table lookup for a current value
to source to the timer input).

I'd expect a small microcontroller would be the easiest way to do the
conversion these days.  A couple of built-in DACs would make it pretty
simple.

-michael

NadaNet 3.0 for Apple II parallel computing!
Home page:  http://home.comcast.net/~mjmahon/

"The wastebasket is our most important design
tool--and it's seriously underused."