Sounds like a job for linear electronics <G>  Think 2 Op-Amps, set up
as voltage comparators, each outputs a 1 when the output is beyond it's
set point;  Something like this {Note that the /|\ is a "Crossover", not
a connection!}  Double-check me on it as it's late & I am in a rush to
get supplies before the Christmas Storm of '98 closes us down here <G>

  BTW, if the joystick has one end at +5 and the other end at Gnd, omit
the 50k resistor there as ground is already handled <G>

  This would generate 10, 00, 01; For 11 in the middle, swap the
connections from the ends of the 10k resistor to the voltage
comparators.

  (You're responsible for power to the Voltage Comparators/OpAmps, just
power them from Gnd and +5 Volts - and you may want to buffer them if
necessary, unlikely though. <G>)

                      |\
 Gnd O---\/\/\--+-----|+\
          40k   |     |  }------  Bit 0
                \  +--|-/
                /  |  |/
            10k \  |
                /  |  |\
                |  +--|+\
                |  |  |  }------  Bit 1
       +-\/\/\--+-/|\-|-/
       |  40k      |  |/
 +5V O-+-\/\/\--+--+
           R    |
                |
 Gnd O---\/\/\--+
         50k

  Mark, mwillis@nwlink.com

Pablo Bleyer Kocik wrote:
>
> Hi!
>     I'm currently building a 16F84-based telescope mount control with
> step motors and I'm using a gamepad as the main user interface
> peripheral. This is a typical Gravis-compatible gamepad, with a nine
> position joystick and four buttons. The gamepad is a perfect solution
> for my control, it works fine and looks great ;^) . However I'm
> looking for a simple converter for the gamepad's joystick; I've used
> PC-like circuits (with 555-like monoastables) and comparators with
> good results, but this is just too much for the simple 3 position
> joystick's stick of each axis (0 Kohms when up, 50 K when middle, 100
> K when down). I need to convert these positions to two bits (10 when
> the stick is up, 01 when the stick is down, and 00 (or 11) when the
> stick is in it's natural position). Any ideas for a _simple_ circuit
> doing this?
>
>                  +--+
> +5V O--\/\/\---> |  |-> bit0
>          R       |  |-> bit1
>                  +--+
>
> R: 0-50-100 KOhms
>
> Thanks and happy, happy holidays! Merry Xmas and a prosperous new
> year!!!
>
> --
> Pablo Bleyer Kocik |"The most exciting phrase to hear in science, the
> pbleyer            | one that heralds new discoveries, is not `Eureka!'
>     @dgf.uchile.cl | (I found it!) but `That's funny...'" -Isaac Asimov
>
>