No Joy with Joystick
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I am having very erratic results using one of the Noble xvl series
joysticks. http://www.nobleusa.com/index2.htm I'm using rc time to check
the potentiometric value but almost any change in the rest of the circuit
causes the value to jump to a different range. I am using a 7805 regulator
with the +5 to a 4.7uf cap. From there I split with one leg going to the
+joystick and the -joystick straight to ground. The other leg goes to the
stamp pin through a 220 ohm resistor. I have used a word size variable to
rule out truncating and wrapping, and my program sets the pin high at the
start of each loop. Even plugging and unplugging the other (y) side of the
joystick changes the variable. I have tried swapping joysticks and checking
continuity between the x and y... everything checks out except the results.
Do I need to isolate each leg of the joystick somehow? I should point out
that this circuit used to work with another joystick that had an open
circuit center position. The new Noble Joysticks have a wiper and the center
position reads half of the available resistance.(center =roughly 5k) The
variable I expect after doing my calculations should hover around 14k which
it does until I plug in the other leg, and the value drops 2000. If I move
the stick in x direction both x and y values change. The specs say that the
new joystick can handle .0125 watt. Does anyone have any suggestions?
Thanks in advance!
Jeff
joysticks. http://www.nobleusa.com/index2.htm I'm using rc time to check
the potentiometric value but almost any change in the rest of the circuit
causes the value to jump to a different range. I am using a 7805 regulator
with the +5 to a 4.7uf cap. From there I split with one leg going to the
+joystick and the -joystick straight to ground. The other leg goes to the
stamp pin through a 220 ohm resistor. I have used a word size variable to
rule out truncating and wrapping, and my program sets the pin high at the
start of each loop. Even plugging and unplugging the other (y) side of the
joystick changes the variable. I have tried swapping joysticks and checking
continuity between the x and y... everything checks out except the results.
Do I need to isolate each leg of the joystick somehow? I should point out
that this circuit used to work with another joystick that had an open
circuit center position. The new Noble Joysticks have a wiper and the center
position reads half of the available resistance.(center =roughly 5k) The
variable I expect after doing my calculations should hover around 14k which
it does until I plug in the other leg, and the value drops 2000. If I move
the stick in x direction both x and y values change. The specs say that the
new joystick can handle .0125 watt. Does anyone have any suggestions?
Thanks in advance!
Jeff