MicroLS (part 1)
MicroLS stands for micro Light Show! Let’s have some fun with Arduino for a time!
Behind the scene of MicroLS are quite powerful functions that most of Arduinoos visitors are familiar with. MicroLS makes an extensive use of two popular libraries: PlainADC and PlainFFT. Both of them have been recently upgraded in order to improve their ease of interfacing. Any Arduino enthusiast will now be able to design fancy light shows using few simple lines of code. And then, that will be your imagination!
Let’s start with hardware. Building a basic MicroLS is really easy: a few passive components are required: 4 or more Leds shall be used for the display, plus an other (optional) one for controlling the conversion rate. Each Led corresponds to the signal lying in a 1/4 of the frequency spectrum. The analog signal comes from an audio output (e.g. sound card). The DC component of the signal is nulled by the capacitor, and a proper biasing is set by a resistor divider bridge.
Here is an alternative circuit: the audio signal is taken from a microphone and amplified with a single stage pre-amplifier. The amplifying ratio is set by the feed back resistor and the resistor wired to ground. Each Led corresponds to the signal lying in a 1/6 of the frequency spectrum.
Advanced users shall feel free to interface Arduino to real spot lights, and add more channels. This question will not be covered in this serie of posts.