I actually have a Sainsmart 5v relay as discussed in a few other threads, but want to try the solid state relay to see if it's less complex to connect (I realize the cost is significantly more, it's for AC only, etc. -- just going for simplicity here).
This is the one I bought: http://www.sainsmart.com/8-channel-5v-s ... duino.html
From what I read, the 3.3v GPIO output should be able to switch each relay without having to resort to manipulating 5v (though I'm not adverse to directly connecting a separate 5v power-supply just to the board).
My main question is: Is this one simple to the point that I could connect a GPIO directly to each input of the relay? Would I need something else in the circuit (outside of the relay's circuitry, of course)? Do I need a resistor for safety or something on this output?