The design and selection of a suitable drive unit for use in mechatronic systems is a process that can be demanding not only in terms of the time required but also in terms of the demands placed on the knowledge and experience of development workers. The development aimed to create algorithms for the selection of compact electric power units based on data from dynamic analyses of the proposed system, with the help of which it would be possible to shorten and simplify the drive unit selection process significantly. The result of the development is a software tool called DrivePicker. Its functions and benefits are demonstrated in the design of drive units for a robotic arm with an angular structure and 5 degrees of freedom. Comparing selected units from two manufacturers (Spinea DS and HarmonicDrive CanisDrive) shows that by using this software tool, we can significantly speed up and streamline the design of mechatronic devices. DrivePicker also has an interface for connection to simulation and CAD systems, which opens up the possibility of further autonomy.