With this handy 7 Pin Mini-DIN Connector you can now jack into the hackport on your iRobot and control it with an Arduino or some other favorite microcontroller that has a 5V TTL UART! You can also power your project off of the internal Create 2's battery. Note that the battery voltage can be as high as ~21V so a buck converter such as this one could be good for getting the unregulated Vpwr from 20V down to a more reasonable 5V

More information on the cable and what each pin is used for in the Create 2 Open Interface Specification

The iRobot Create 2 is a time tested durable mobile robot platform built from remanufactured Roomba robots so instead of spending hours, or days, or weeks trying to build a functional robot and figuring out your power supplies and motors, just hack the iRobot! Check out the tutorials and guides over at iRobot

Each order comes with a single cable, iRobot Create 2 not included