How do you sync Christmas lights to music?

Answer 1

There are a couple of ways, but the simplest (though probably the most expensive) is to buy some DMX-controlled light packs and a USB-to-DMX controller for your computer. You can then program the DMX channels to turn on and off whenever you like. It won't automatically sync to a song, but you can play the song and tell the controller "turn this strand on at 3:03, turn it off again at 3:07" or whatever. To give you some idea of the cost, a cheap relay kit for a single channel goes for around $40, and Chavet makes a 4-channel dimmer/relay pack you can pick up for as low as $80-90 (list price is around $120). The control unit... expect to spend about $200-300 on that. You can build one for considerably less if you're talented in the soldering arena and have access to an EPROM programmer.

Note that 1 channel allows you to turn 1 circuit (a string of lights, or possibly several; the limitation is usually the overall wattage, with around 500-600 watts being pretty typical... this is a lot of Christmas lights, which are usually around 25 watts per strand). However, if you want some of the lights to come on some times, and other lights to come on other times, you'll need a separate channel for each set you want to be able to turn on or off independently. If your goal is just to get your entire tree to blink to "Is Zat You, Santa Claus?" then one channel is fine. Replicating the YouTube video in Related links would require dozens of relays, though it might be possible to handle some of the related "bouncy" lighting (what lighting technicians call a "chase", like the row of trees in front) with a single (more sophisticated) unit. (Midway through the video there's a link to a "Behind the Scenes" video where he actually shows the equipment he's using).

A cheaper way that would require more electrical engineering and soldering ability is to use the parallel port on a computer to drive relays (probably by going through some op-amps to electrically isolate the relays from the computer... you don't really want to be shoving even the kind of current needed to operate the relays through your parallel port). You'd also have to write the control program, but this is actually pretty simple compared to building the controller itself.

Your best bet, if you're neither an electrical engineer nor an entertainment lighting technician, would be to look at some of the stuff sold for DJs.