Fritzing

uses Transistors to controll 4x 230V Relay that needs 5V Power with GPIO.

There is a very cheap Relay for 4/8Channel available for Ardunio, but it needs 5V to run. This Board should close the gab but is not yet testet. This Board might fit on the last 6 Pins (uses 5) of Raspberry PI2, it needs a seperate cable to power 5V from the other side of the GPIO. 5V may get powered from external if Ground is connected from external, too. Resistors should work from 150-200Ohm, Using different Transistors or Relay may cause other Resistors. As the Relay needs 0.07A, 0.007A should be enough to keep the Transistor 2N5550 (1:10) saturated. I calculated that there should flow a current of 0,014A on Base with 150Ohm Resistor (if i understood right, 3,3V are reduced by 1.2V from the Transistor leaving 2.1V / 150Ohm=0.014A ?