Sound Cameras by eric archer
Although human eyes are marvelous sensors, they don’t tell us the whole story. The effect called persistence of vision limits our ability to percieve rapidly changing light sources. Thus if a light source is blinking or modulating faster than about 20 times a second, it appears continuous. However, there are many types of light around us that oscillate and modulate much faster than that, coming from both nature and technological sources. I’ve been curious to hear these modulations for quite a while.
http://ericarcher.net/devices/sound-cameras/
