My final project did not change that much from the original proposal made on Week 1. I was always interested on relating sound and light in interesting and attractive ways. As first steps towards that goal I made an initial attempt in the week of input devices, by creating a microphone board and try to read input out of it. For my final project I changed the board design to the one of the electret microphone board of Sparkfun. The output devices would be several RGB LEDs that would be arranged inside a wooden box. The would be hidden behind thin wood, so they would only be visible when they turn on. A microcontroller board was used in which an embedded code would analyze the sound coming from the microphone board. The sound signal would be analyzed through an FFT (Fast Fourier Transform) algorithm which gives as an output the intensity and frequency of the sound signal. That algorithm was modified in order to relate the sound intensity to light intensity through PWM signals for the RGB LEDs, and sound frequency was related to different colors that would be represented with different intensities of red, green or blue in the LEDs. All these electronic devices are powered by one power distribution board, which has a 9V battery connected to it, and three MOSFET transistors for each different color of the RGB LEDs. All of these electronic components were fitted inside a plywood box whose parts were designed in Rhino, laser cut and then assembled as a press-fit kit.

To download all the code and electronics design files you can click here.

Below there's a picture of the electronics used. The power distribution board, electret microphone board and RGB LEDs boards were designed using Eagle software. There is also a picture of the microcontroller board from the Barduino project, inside the wooden box.

Below there's pictures of the different stages of development of the wooden box. From outlines for laser cutting, to 3D preview, to the real box assembled together from several laser cut plywood pieces.

Below you can see two videos of the project working.