Add a rolling interface with your project with this Panel Mount USB Trackball with Three Buttons that is super easy to use and interface with. Simply plug it into your computer (desktop of single-board-linux type), it will appear as an external mouse with left and right buttons plus a middle button.

Perfect for use with an embedded computer setup that needs a pointer but you don't have a touchscreen, and not enough space for a mouse.

We also have a similar version, but with a trackpad instead of a trackball.