__________
                           |
   ___  _______  __________|
  /   \/       \/          |   3.5mm Stereo Jack
 |    ||       ||          |
 |    ||       ||          |   (Mono version has right and
  \___/\_______/\__________|   ground merged in single pole)
                           |
    ^       ^        ^     |___________
    * LEFT  |        |
            * RIGHT  |
                     * GROUND
                                         ___________
                                        |           |
                                        | PIR       |
                   LEFT =---------+     |           |
Soundcard INPUT  GROUND =--+      |     |           |
                           |      |     |           |
                           |      +-----|-o/  NC    |
                           |      +-----|-/  Switch |
Soundcard OUTPUT GROUND =--+      |     |           |
                   LEFT =---------+     |           |
                                        | 12V Power |
                                        |  +  -     |
                                        |__|__|_____|
                                           |  |
                                         To supply