Electronics question in regards to homemade DDR pad.

[Klaiviel]

I am making a home made DanceDanceRevolution pad with 6 buttons up down left right start and select using the following ps2 controller (http://www.digitaltorque.com/mydancepad/?display=5%20-%20wiring%20the%20pad%2Fclosepcb.jpg). ps2 controllers are supplied with 5 volts. What I want to do is add lighting to the up down left and right arrows which will be plexiglas using LEDs. If the LEDs all have 3.6V forward voltage and 20 mA forward current, how many would I be able to add under each plexiglas piece before having to worry about damaging the PS2 controller? This is keeping in mind that it is possible for someone to hold down all 4 buttons at one time and that the resistance of 10' of cat5 cable (the ammount used in between each plexiglas switch and the controller) is about .3 ohms. Also which would allow more LEDs, wiring them under the step in series or in parallel? Thanks! (http://www.digitaltorque.com/mydancepad/ Is the site of the pad design in case that would help)

 

[Geo]

I`d guess the 5v will be for logic switching only (ie: logic high/low) so the current capability of the circuit will be very limited.

To avoid the possibility of damaging the ps2 you might consider adding an additional (insulated) pressure switch plate to each pad and using an external supply solely for the leds.

That way you can use as many leds as the supply can handle, or alternatively, size the supply to the amount of leds you want.