Vast VU Meter

This is an existing personal project I'm building a prototype for to pitch to my university. I plan to work out the kinks in the HacDC space. I've laid this out pretty thoroughly on my blog. Here is a quick synopsis:

I want to take a row of windows (or more, as money allows) in the building and place lamps in them to form a vertical bar VU meter showing the volume of the radio station's broadcast. You could tune in to the station during the evening and watch this huge column of light on the face of [a 22 story building on campus] leap up and down in synchrony with the music. You could tune in to the station during the evening and watch this huge column of light on the face of POT leap up and down in synchrony with the music. The signal we want to represent is already available as radio broadcast on every floor. So instead of switching a huge number of lights from a central system, we can put a radio on each floor and have each set of lights switched autonomously in response to the signal it receives.

So the basic plan is to have a simple lamp with, lets say, three 100 watt bulbs in each window. You have a relay that can switch the bulbs on and off quickly in response to a low voltage signal. This signal is provided by a simple circuit that detects how loud the signal coming from the radio is, and while it’s above a certain threshold, activates the relay to turn on the lamps. By setting that threshold slightly higher on each successive floor, you’ll get that VU meter effect.