The Raspberry Pi Zero Dynamixel Hat it's an easy to use hardware that allows you to connect and communicate with Dynamixel Servo Motors by using the Savage Electronics AX interface circuit, providing the half-duplex communication needed by these motors, its implemented in it a voltage converter for all the signals to the Raspberry allowing a secure communication in terms of logical levels.
It also implements a MAX25232ATCG/V+ which is a synchronous step-down DC-DC converter optimized for applications with high power density, This regulator will let you power your Raspberry directly from a battery and also provide power to your motors.