Customized ATX power supply

An old PC power supply! Who does not have one...? For my arduino project I needed a reliable and powerful power source, because of the halogen lamp used to warm the hatch box, so, layed hands on work and converted an old PSU. Let us see how!
As you all may know, these PSU's once connected to the AC power, are ALWAYS in charge, for that I connected an LED, and an other for when the power unit is really on. If your power supply has an on/off button, you can skip the switch connected to the green wire, and just short-circuit it to ground, using the native on/off button to switch on and off.
Nevertheless the left image explains the wires needed to be worked to achieve best results. Did not use the resistor.
The yellow wires are +12V, the blue -12V, the red +5V, the black GND, the yellow +3.3V, white -5V, as you can see on the next picture. You can now drill the box and use some connectors with a fuse to protect the PSU, and voilá!
I used these links, an instructable and a wikihow as an aid to the work. Good luck on your project! Feel free to contact me.