Pulling It All Together

A project log for Wide Area Light Grid

Control per-pole LED lighting in a grand space

ethan.dicksethan.dicks 08/21/2014 at 07:150 Comments

The key elements of this project are:

  o Multiple inexpensive AVR-based RS-485-connected RGB LED controller "nodes"

  o One network "master" node that sends out color events to each light node.

  o One or more input devices that sense the environment (light, sound, user-manipulation, etc) to influence the master node

  o Power and wiring to span the 6,000 sq ft of installation space

The RGB nodes themselves are quite simple: an AVR ATmega processor with an RS-485 interface chip (75176 or similar) and three transistors on three PWM-enabled output pins with enough drive to light 20 RGB LEDs (250mA per channel) running a simple sketch to listen for DMX packets coming in from the master node.

The master node is also quite straightforward: a Linux-based machine with Open Source application code that processes input from a wireless input device into 48 channels (R, G, and B for eight pairs of pillars), wraps them up into a 512-channel DMX packet, and blasts it over the wire to all the lights in the room.

The input devices are also AVR-based, with Bluetooth or X-Bee or other simple wireless serial extender, and consist of an input stage (MEMS accelerometer, buttons, sliders, microphone, pressure sensor, etc), some code to translate the widely-varying raw input to a small list of actionable commands (up, down, raise, lower, slide, cycle, etc) that are meaningful to the master node.