This "light organ" transforms audio signals (music) into light events. Such devices were very popular in the 1970s. Here's how it works:
Your iPhone, iPod Touch or iPad picks up the music with its microphone. The iPod Touch doesn't have a builtin mic, but you can connect an external microphone or headset. The music signal will be split into three "bands": Low, middle and high pitched sounds. Each band is assigned to a light bulb. If the signal reaches a threshold level the bulb will be switched on.
In other words:
The three light bulbs flash in time with your music.
To complete the retro feeling and to allow playback from your builtin music player,
the app features a "casette player". Not everyone might be familiar with such devices,
but be assured: They were very popular too.
Even the control interface is from the 70s. It has some scratches and stains, but it still works...
You can switch over to "projection mode". Place your device close to a wall and watch the reflections. This can look quite impressive with an iPad due to its large and bright screen.
Why do we have to use a microphone?
Older iOS versions don't allow an app access to the music itself; It may only control the builtin player. We don't want to force users to update in order to use this app.
And there's another advantage:
You can use your Lichtorgel app with any music already playing. Just turn it on and have fun.