Magic eye spectrum analyzer

its goddamned magic


If Nixies aren’t cool enough, maybe it’s time to step it up to magic eye tubes.

Magic eye tubes are, like Nixies and Dekatrons, display tubes. Unlike the alphanumeric characters of Nixies or rotating points of light in a Dekatron, Magic eye tubes are either bar graph or ‘Pac-Man’ displays that were used to show the signal strength of a radio station on very expensive radio sets.

After doing a few experiments with tubes, [sylvain] thought it would be cool to do something with magic eye tubes. He sourced eight vertical ‘bar graph’ magic eye tubes and built an audio spectrum analyzer.

One of the more difficult things to do was to compute the power levels for each frequency band. There are a few graphic equalizer ICs available, but [sylvian] decided to go the old-school, harder way by putting an FFT algorithm on an ATMega624.

An impressive piece of work that would look amazing next to a nice tube stereo system.

ATtiny controlled magic eye tube

In the early days of broadcast radio, the most expensive radio sets were extremely impressive pieces of furniture. With beautifully crafted wooden cases polished to a high shine, these wireless receivers were the focal point of any family room. Some of the most expensive radio sets even included a visual indicator signaling the strength of the reception, something [Marcus] decided to re-engineer using an ATtiny85.

The display tube in question is an EM800 magic eye tube, used in radio sets, stereos, and electronic test equipment as a rudimentary display indicator. By applying a control voltage (from 0 to -10V), the illuminated display can be controlled like a bar graph display.

[Marcus]‘ tube display is built around an ATtiny85 microcontroller, using a homemade PCB. It’s a fairly simple build, once the issue of supplying 250 Volts to the EM800’s anode is taken care of.

In the video after the break, you can see the bar display of [Marcus]‘s magic eye tube slowly growing and receding, perfect for either displaying the current CPU load on your computer or anything else a dynamic bar graph display would be used.

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Kinect produced autostereograms (Magic Eye pictures)

[Kyle McDonald], working collaboratively with [Golan Levin] at the Studio for Creative Inquiry, has come up with an application that can produce autostereograms. These are pictures that appear to be three-dimensional thanks to a visual illusion created by forcing your eyes to adjust focus and vergence differently than they normally would. The program is called ofxAutostereogram and it comes with a couple of examples. Both are show in [Kyle's] video (embedded after the break), starting with a depth image of a shark. This combines with a texture tile, then is processed through the openFrameworks software in the package to produce the final image.

If that’s all it did you might find it rather unimpressive… these images have been around for some time although they were never so easy to produce on your home computer. But the second example is a pretty fantastic one. You can use a depth image from a Kinect as the starting point. As seen above, there is a preview window where you can adjust the clipping planes in order to include the correct depth. This also allows you a preview of your pose. Once it’s just right, snap a pick and process it through the software.

[Read more...]


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