Thanks Charles!!

That surely helps things getting visible so that all can talk from the same page.

If I was going to build this circuit I would use 10K ohm pullup resistors on the switches and I would add an additional 10K pullup on the INT0 pin. I would also use diodes that are specified at very low forward voltage drop. Thus I can be reasonably assured to achieve a good V_IL on the INT0 pin whenever one of the switches is pressed.

Michael Karas