Right now for testing I'm powering the thing with the +5v line of the raspberry pi, but fluctuations are too high for the pi so I want to power it from an external source. I'm running out of 5v power banks (already powering the Pi's with them) my question is .. would it be ok to power the PWM extension board (and there fore the servos) with 4 x 1.5v standard batteries? This leads to 6v, not 5v. Could I just plug a resistor in series, or even a diode, to bring it from 6 to 5?
My main concern is on the servos (the board keeps a line for the power on the servos and the logic will be powered with 3v3), will they overheat? will the current on the batteries be enough to move the servo? will they last just for some minutes?
Is there anything else I should think about?