I’ve been slowly working on this project for the past month or so. I finally have some time to share and post-up what I’m working on.
I know there are commercial products available, but then what’s the fun in that!
What I want is a Fully Automated LED Primary Lighting System which can control separate white and blue high-powered LED modules on my 45gal bow-front tank. What I mean by fully automatic is that I’d like an intelligent light controller which uses user-defined pre-set schedules to slowly ramp the lights on and off accordingly.
Therefore this project has two major endeavours: 1) a high-power LED array modules, 2) logic controller.
This diagram shows the entire circuit overview:
For the high-power LED arrays, I settled on Luxeon Rebels, a switching 48V DC power supply, and typical current protection resistors. I know many applications are using very efficient buck/puck drivers to power LEDs but that won’t work for this project since I will be doing my own PWM (pulse width modulation) to control LED intensity. Some buck drivers do allow for a dimming input, but this is not the route I’m taking. I designed these LED arrays as to minimise the current limiting resistor as much as possible.
For the logic or controller portion, I went with the open source Arduino micro-controller platform. Arduinos are so cool and easy to program with simple C++ like language and USB right to your PC. This allows me to write software (aka firmware) which tracks time of day and the user-defined lighting schedules. Then the controller runs on it’s own.
Here’s a detailed look at the logic section:
The controller simply sneds TTL logic levels to the four MOSFET’s which effectively blink the LED arrays on/off at various duty-cycles. It’s so fast that the human eye (or fish’s eye) sees a dim LED. This is known as PWM and is the industry standard way to dim LED lights.
Read more: LED Sun rise/set Arduino Proj