jombo:
Hi fungus,I did read your previous post. From what I understand I can hook up 3 batteries to the servo and the motors. also have the 3 batteries connected to a USB dc converter. The dc converter will allways power 5 volts to the raspberry pi.
Also I need to put decoupling capacitors between the USB DC converter and the raspberry pi.
No...I mean you have five batteries but you should only connect the dc converter across three of them, ie. connect a wire in between battery three and four.
The dc converter will compensate for any voltage drop caused by the motors, it puts out 5V no matter what the input is (so long as it's within range).
Ideally though, you don't want any voltage drop. Rechargable batteries can put out much more current than Alkalines. If you're using Alkalines you should change.