A number of external controllers with realistic controls have been manufactured for use with the games:

It also supports an external footpedal controller, and tape backup.

This system is composed of two distinct parts: the implant and an external controller.

The implant is lodged in the visual cortex and wirelessly receives data and energy from the external controller.

Carbon brushes connect the slip rings to an external controller such as a variable resistor that allows changing the motor's slip rate.

In theory, if you support one external controller, you support them all.

In other cases, a number of different machines are used with an external controller and human or robotic operators that move the component from machine to machine.

Filter control of the main preset sounds is not user adjustable other than via an external controller.

Complete integration of motorized external controllers.

It's actually an external controller for the Eee's solid-state drive.