Monday, July 1, 2013

Controlling the lights

The lighting system
The lighting system for the tank will involve a large number of separately-controlled color channels, spread out over a number of separately-controlled lighting zones. As previously described, there will be four fixtures suspended over the tank. These four fixtures will be divided into three lighting zones -- left (or East), center, and right (or West). Each zone will have 8 color channels (royal blue, 5000K white, 2700K white, violet, indigo, cool blue, turquoise and red).

Given the number of LED emitters, drivers, color channels, heatsinks and power supplies, it's easier to visualize all of this graphically. The "mind map" on the right (made with FreeMind) helps to illustrate all of this.

The driver breakout board
The "Driver Breakout Boards" referenced in the mind map have been a time-consuming project recently. Because all of these LEDs will require a total of 42 Mean Well LDD-H drivers, it would be a rats nest under the tank if there weren't some way to wrangle all of these circuits into order. Inspired by the work of others on Reef Central, I decided to try my hand at printed circuit board (PCB) layout using the free version of Eagle. After many, many revisions (and much trial and error), I've arrived at version 1.7 of the board design, which I will shortly have fabricated by iMall. It permits six of the Mean Well LDD-H LED drivers to be cleanly mounted to a circuit board, which can in turn be mounted in a plastic enclosure to keep everything tidy and reasonably protected from the saltwater environment around the tank. These boards will also require a good bit of soldering know-how to put together, which I completely lack, so I ordered several spare boards to practice/make my mistakes on. I've also got a combination soldering iron / hot air re-work station on the way from'll throw myself into any project that will give me an excuse to by new tools.

If anyone is interested in downloading a copy of the breakout board design, I'll be happy to post it up.