After five years and about 2 million units sold, iRobot Corp. of Burlington has overhauled its Roomba robotic vacuum cleaners.
The latest versions are smart enough to untangle themselves from electrical cords. The high-end model can also use radio beacons to find its way through multiple rooms, then return to its base station to recharge its battery.
IRobot also toughened up the new Roombas ($299 or $349). They're made of heavier, more durable materials, with modular components that are easier to replace. Software will halt the rotating brushes if a cord or tassel gets tangled. Then the cleaner will slowly extract itself and go back to work.
And both models have built-in voice tutorials that explain the Roomba's functions, at the touch of a button.