I want to do a robot using 2 continuous servos (5V, 15-200 mA) and 2 smaller regular servos (5V, no current info, but its this one: EMAX ES08A Servo Specifications and Reviews).
My question is, at what point (current load, number of servos, etc.) do you need to use a motor shield or some other method to control the servo?
I think that the "limit" is 3 (or three-ish.)
All you need is a 5V source exclusively for the servos; you don't want to run 4 from the Arduino's 5V, that's excessive demand for it.
Just a little bit of a curiosity follow up question:
What makes you say 3-ish? Does the PWM get a little imprecise when the arduino is running a bunch of them? Sorry for all the questions, I'm new and just want to make sure I understand.
Best place I've found to read about servo powering is DuaneB's stuff
So yes the decision on external power or Arduino 5v is a current thing, but it's so little hassle to hook servos up like DuaneB shows, it's worth doing as a matter of course even for 1 imo.
From a control (as opposed to power) point of view, the servo library has plenty of connections for your 4.....