Walcott Visualization

From SlugWiki
Revision as of 18:35, 3 July 2006 by Wrchan (Talk)

Jump to: navigation, search


The Walcott visualization integrates a set of rewired christmas lights into the Bemix system. A custom XMMS plugin running on Cocoa Table calculates five 0-255 values based on Fourier transform of the music playing in the lounge. These numbers are wrapped into a 4E Network packet and sent to the serial port to a PIC microcontroller. The PIC parses the packet using BemixOS technology and sets the brightness of each color of light using PWM.


The visualization uses a PIC 18F1220 to decode a 4E Network packet containing six 0-255 values. The packet should look something like:

(channel 1)
(channel 2)
(channel 3)
(channel 4)
(channel 5)
(channel 6)

These values become the duty cycles of six software PWMs running in the main loop of the firmware. The latest version of the firmware is available at svn://bemix.mit.edu/var/svn/repos/visualization/pic.

The PWM outputs are fed into TIP110 power darlingtons through 1K base resistor. The power transistors are connected to a set of modified christmas lights in a common emitter configuration. Each TIP110 drives an array of 2 lights in series and n in parallel. The lights are powered from the +5V rail of a computer power supply.


See Also