This is a simple aquarium controler. It is based on Arduino and TMP36.
The leds 2 and 3 can be replaced by PWM controled led drivers and leds 4 and 5 by optocoupler controled relays.
The code is here: https://github.com/flav1972/aquarium
The project page is here: http://wiki.flav.com/wiki/Aquarium_Controller