It has a usb-c input which is usually 5v, but can I connect 6v or 7.4v and expect the servo to receive it?
Or the board will just convert the input to 5v and feed 5v to the servo?
Hello,
The board was originally designed to only accept 5V from either a Raspberry Pi or Sphero RVR. There is no on board voltage regulator to drop your target voltage down to 5V. I would strongly advise against using the pHAT in this manner.
Technically you could modify the shield to use an external power source that works at 6 or 7.4 volts but since the shield was never designed for this it’s possible to kill your shield and Pi if you don’t get it exactly right.
You’d be better off (safer) building your own adapter board that injects your battery voltage to the power pin for the servo and only connects signal and ground over from the Servo pHAT.