variable Power Supply

I am looking to make (Unless there is a nice cheap solution) a variable power supply, which I can plug into my mains (230v) and have a chosen output (230-0 both AC and dc). I also hope to integrate the Arduino into the project, by using it to project an lcd display. i am currently completely in the dark about methods used to step down/up voltage (besides basic knowledge of transformers, how they work). I am asking whether this has been done here before? If so can anyone refer me?

If not I look forward to any reply and suggestion on this project (please try to post sufficient detail as to keep me ffrom replying several times :slight_smile: )

Any suggestions?

For variable AC 0-230V Power Supply you can use Variable autotransformers

As for DC 0-230V, what current are you need? how many Amp?

No more than 5 are needed.

At 230V with 5A output that will be more then 1150W,

Here is one of the design using LM317

http://www.tubecad.com/2012/04/blog0227.htm

Edit:
High voltages of 230V and the available current of several amps can be lethal; exercise caution when building, testing, and using this circuit.