Interactive Halloween thunder effects from Brian Enigma:

The device is comprised of two boxes, sep­a­rated across the room and con­nected by a four-conductor tele­phone cable. Next to the entry­way is the “brain” box. This is connected to the LED strip above the garage door. It houses the Arduino and sound gen­er­at­ing hard­ware (Wave Shield). It is also hooked up to a small stereo. On the other side of the room is the “remote con­trol.” This is the box with but­tons for pick­ing a set of ambi­ent light­ing colors as well as the hid­den foot switch.

The tele­phone cable pro­vides power and ground, but also has a “sense” line, hooked up to an analog-to-digital con­verter on the Arduino. Because of the resis­tor matrix in the box, each but­ton will return a dif­fer­ent volt­age back through the sense line. If you have used iPhone or Android head­phones with inte­grated vol­ume and answer but­tons, this is the exact same con­cept but blown out to four but­tons and a foot switch….

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