Arduino, Resistor, And Barrel Plug Lay ... to short circuit just the data, but not the DC. This is still impractical, ... I could have made it look like I was walking into an unlocked door to a ...

The larger resistor (looks like 4.7 megaohms here) sends a signal through the copper pad which is read by the secondary pin. ... Duh, the Arduino is just an AVR with a bunch of premade libraries.