Working on a robotic arm and prototyping controlling two servos with a joystick module (one per axis). The code and machine work fine while my arduino pro mini is connected to the FTDI basic, but the servos just behave erratically when the FTDI is disconnected. At one point the pro mini smoked, and I don't know if that means I just need a new chip, total noob here. Any advice?
Smoking is bad for your Arduino! Means at least one chip is fried.
But why did it burn out? Probably trying to power the servo from it? Servos must have separate power from a logic device, they take much more current and put shedloads of noise and spikes onto the power rail (not good for any logic circuits).
Something like a 6V 2A supply is needed for the servos, common the ground with the Arduino ground.
Do you see any obvious signs of burnt chips? How were you powering things? Which servos? Can you post a wiring diagram showing how you have everything connected?