You're probably quite familiar with iRobot's (NASDAQ:IRBT) household products: pool cleaners, gutter cleaners, and of course the Roomba vacuuming robot. Defense and security products, however, make up about 18% of the company's revenues. These include various unmanned robots that can carry heavy objects or provide reconnaissance.

Our roving reporter Rex Moore caught up with iRobot at last week's big conference in Washington, D.C., put on by the Association for Unmanned Vehicle Systems International. In the second of this two-part series, iRobot's Mark Belanger explains the 510 PackBot, which is used by troops in Afghanistan, Iraq, and even domestically by law enforcement officials.