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Neon Lamp Traces Sound Wave's Picture

Source: Popular Science ( More articles from this issue )
Issue: Sep, 1950

Neon Lamp Traces Sound Wave’s Picture
That’s a sound wave you see in the picture above. Here demonstrating how an acoustic lens focuses sound from a horn, the wave was made visible with the device at left—an aluminum rod with a microphone and a neon lamp at the end. A small motor swings the rod in a wide arc, scanning the area. The microphone picks up the sound and turns it into electric current to feed the lamp. Wherever the sound is strongest, the light is brightest, and the wave is traced out. A complete sound photo, such as this from Bell Labs, takes 10 minutes exposure.

Nuke Lab Builds ‘Beating Drum’ Sonic Blaster

soundwavesA Tennessee lab primarily responsible for building components for nuclear weapons is branching off into the nonlethal weapons business with a device that could repel terrorists and criminals.

Called the Banshee II, the weapon emits a piercing 144-decibel sound that is designed to be more than just annoying. “It also has a frequency-switching system that pumps your ear drums, so it sounds like there’s a drum beating there,” the inventor tellsKnoxnews.com. “You physically feel it in your ear drum.”

The Banshee is the brainchild of Fariborz Bzorgi, a government engineer described by Popular Science in a profile several years ago as the Department of Energy’s “Gadget Guru” because of his prolific record of inventions. Bzorgi works at the Y-12 nuclear plant in Tennessee.

The first iteration of the Banshee — an adjustable acoustic hand grenade — was designed to blast the Taliban and Al Qaeda out of caves in Afghanistan. That idea never quite caught on with the military, but Bzorgi hopes the Banshee II could have broader applications for law enforcement, including an alternative to the Taser, Knoxnews.com reports.

One of its selling points is that it is designed to be low cost — Banshee II is made from little more than off-the-shelf hardware, amplifiers and a 9-volt DC battery.