Playing creepy tunes with monitor radiation

In this strange video, BBG reader Sergio demonstrates a device that can detect monitor radiation from an old CRT and represent it as noise. While there are security-related uses for such a thing, here it instead plays the tune generated by patterns of on-screen light.

[#1 posted by aeflash , September 23, 2008 8:07 PM]

Third movement from Beethoven's "Tempest" piano sonata.

[#2 posted by technogeek , September 23, 2008 8:43 PM]

The "strange device" is probably just an AM radio, picking up the switching transients. At one point in the computer's evolution this was briefly popular as a debugging tool; with experience you could hear which loop your program was in, and thus get a sense of when it wasn't where you thought it should be.

[#3 posted by matthewroedder , September 23, 2008 8:48 PM]

leno's lame.
so's that choad.
one strike for boing-boing.

[#4 posted by guy_jin , September 23, 2008 9:12 PM]

After hearing that I half expect some old computerized voice to start reciting numbers in German.

[#5 posted by Not a Doktor , September 23, 2008 9:25 PM]

INFERNAL BOX OF MADNESS

[#6 posted by Vorn , September 24, 2008 2:05 AM]

The music selection is appropriate, seeing as the usual name for the capture of these kinds of emissions is TEMPEST.

http://en.wikipedia.org/wiki/TEMPEST

[#7 posted by a random John , September 24, 2008 1:01 PM]

this is simply the reverse of what I used to do as a 10 year old: plugging the RCA jacks from my stereo into the Video In jacks of a monitor or TV. You could then visualize the sound waves and they appeared as bars. Thicker bars were lower notes, thinner bars were higher. Brighter was louder, dimmer was softer, etc.

What they've done here is just put the bars up an then use the fact that a CRT is incredibly leaky to convert it back to sound. Oddly, I did this as a child by using a video camera to record the visualization on the monitor and then playing the video back out through a stero in order to hear it. Sounded like crap, but your could make out what it was.

I've written an itunes plug-in to simulate the original visualization but it isn't nearly as pleasing as the analogue original and gives me quite a headache.

[#8 posted by Anonymous , September 24, 2008 3:31 PM]

http://www.erikyyy.de/tempest/

The Download is there, for anybody who still has a CRT and an AM radio.