Look at link in my sig, look at the Wiki for Pi, do a google search for FET level translater. Even look at the often quoted on these forums Sparkfun 2 or 8 channel level translater.
Stop posturing and do some simple searches.
As an example it is possible to get in one off quantities 8 chnanel BI-directional level translaters ICs for less han 2 pounds, more often than not a single direction relay will cost the same possibly even get two, but use many orders of magnituide more cuirrent.
Relays need proper driviung and protection.
Last edited by techpaul
on Tue Oct 02, 2012 8:09 pm, edited 1 time in total.
Just another techie on the net - For GPIO boards see http:///www.facebook.com/pcservicesreading