Using digital pins as GND

I am working on an arcade stick that is feeding data in to an arduino, which will then either send that line to GND or HIGH. Arcade sticks work by having all the buttons daisy chained on the GND side, and the positive leads connecting to their own specific pins on an IC. WHen the button is depressed, it connects the positive terminal to GND, which the IC interprets as a button being pressed. To keep pin count low, I would like to just branch the positive lead of the buttons to their own arduino pins which will be able to send the line to GND or HIGH as it sees fit, making the arduino a sort of virtual button pad.

I was wondering if this was possible. If not, do arcade sticks require a "true" GND like the specified arduino pin?

sounds like a big pain in the butt over running one common line, how do you expect to detect changes in the switch if your pins are all switching themselves?

Analog values, different value resistors. Yes it can easily be done... But for a different reason, Why? are you trying for AI... to beat the game?

Doc

even with that you still eventually have to run one end of the chain to ground

I envisioned some complex multiplexed rig where up could be the + side for up, or the - side for down, based on what I understood from the op

the thing I dont like about making a resistor + analog setup is the chance you hit 2 switches at once and it falls within a acceptable range for another signal, though that's reduced on a joystick

whoa whoa whoa, so what is this talk about resistors. I dont understand how you would set this up. So you cant just use the pins as GNDs? The easy way to do this is to setup some pins that act as virtual buttons. But this would require double the number of buttons (15+).

dirtshell:
whoa whoa whoa, so what is this talk about resistors. I dont understand how you would set this up. So you cant just use the pins as GNDs? The easy way to do this is to setup some pins that act as virtual buttons. But this would require double the number of buttons (15+).

Yes, you can just use the pins as grounds although it is rather a waste since you might just as well connect whatever you want grounded to the Arduino's ground. In terms of switches connected to Arduino input pins you can arrange the hardware so that the switch pulls the input high, or so it pulls it low.

The point of using resistors is that you can connect multiple buttons to a single Arduino input pin by connecting each pin through a cunningly designed circuit that produces a different voltage for each possible combination of buttons pressed. If you're running out of pins, you might consider that. If you aren't, you don't need to worry about that.

All right, thanks, i figured there would be some EE magic going on.