Thank you all for your great help in the past. I'm trying to build a contact switch so my Drawbot (http://marginallyclever.com/drawbot) can auto-center after being calibrated.
I have a wire to 5v and another to A0 with exposed leads. I expected A0 would report LOW most of the time and HIGH when the pen holder bridges the leads. I'm getting weird bouncing, sometimes even when I'm not touching the leads. I've checked that there is no accidental contact between the leads.
Please. What am I doing wrong? In a perfect world I can get this to work without having to add resistors. I don't mind the bouncing so long as it only happens when I'm bridging. Thank you!