Beginning the Aquarium LED Lighting Project
I’m a software guy that dabbles in embedded programming, and I was recently asked if I could build an LED lighting system similar to the Ecotech Radion set. I knew it was way beyond anything I had done previously, but he said he was fine with the risk anyway. So, I got started on how I would design the system. First, I needed some requirements (of course, they’ve changed drastically over time).
- The project should control up to 6 channels of lights, and each channel must be individually dimmable.
- The system should allow direct control as well as scheduled settings to simulate sunrise, sunset, etc..
- The system should be modular since I’m going to screw things up and change my mind.
- The system should require only 1 control unit, regardless of the number of fixtures.
Choosing the lights (LEDs)
It was decided that the system would use the same colors as the Ecotech product, and the LEDs were purchased from RapidLED.com. We also got a 6” x 10” heatsink to mount the LEDs.
- 4 Green
- 4 Red
- 8 Royal Blue
- 8 Blue
- 8 Cool White
Selecting a power source
The first challenge was to figure out how to power these lights. Metal halide lights can suck down power. I have 3 fixtures that pull 400 watts each! Since this set up would use LEDs, the power consumption would be closer to 150 watts.
After looking for a suitable power supply, I decided to use surplus ATX supplies. While 24 volts would be a better choice for powering the system, the fact that we have a ton of PSUs at the HackRVA hackerspace waiting to be used in some projects made these a more alluring choice as it’s pretty easy to find a PSU that can provide 150 watts. The trade off is that the system will be working with 12 volts instead of 24. This means the LED channels have to be shorter since each LED drops around 3 volts.
The next step will be figuring out how to wire and drive the LEDs.