Nitelite

The Nitelite is a portable VU-meter for decorative purposes. The Nitelite electronic jewelry was developed in 1980 and produced from 1980 to 1985. The device contains a small microphone which registers the surrounding sound level, causing the LEDs to react correspondingly.
A nice aspect of the Nitelite is that all functional electronics are visible on the front, rather than being tucked away in plastic. Because of this, the Nitelite radiates a much greater 'hi-tech feeling' than it would have otherwise.

During the Eurovision Song Contest 1984, the woman presenter of the show was wearing a Nitelite. (click photo to enlarge)