5v down to 3.3v for 3.3v sensitive devices

wanderson:
You need a regulator for 3.3v, but the Arduino's usually provide that. You can get by with a resistor divider for data lines in some cases, but a level converter is a better general choice.

Thanks for the advise, do you have a recommendation on a particular device?

I will do some searches myself now so I can get familar.

Cheers

Chris