If you have an old ATX power supply lying around the home then you will be pleased to know that you can use it for more than just powering your computer motherboard. A typical one normally outputs +12, +5 and +3.3 volts which is enough to power almost any small home electronic device around the house, for example you can charge your phone, power an LED strip, a car amplifier, car radio and even re-charge your Car Battery! Be warned though if your car battery is too weak you could overload the power supply which will cause the automatic circuit protection to trigger so to be safe you might want to add a few resistors in series.

Here are the colors and there values:

A computer power supply is basically a step down AC to DC converter so let your imagination run wild. Here are some examples of electronic devices I have personally powered using my old power supply.

LED strip