The Polaris 9400 Sport Robot cleans your 40-foot pool in 2 hours

So that is not a particularly long pool, but with that design and all that advanced technology crammed into its body, I’m all for it ! See Zodiac Pool Systems and Polaris, via Engadget

The ActivMotion Sensor in the 9400 uses an accelerometer, much like those used in electronic stability control systems in cars, or in smart phone and tablet devices to align the screen vertically or horizontally depending on the angle in which the device is held; the accelerometer automatically senses cleaner position. It measures force to determine 3-dimensional position, such as deep, shallow, horizontal or vertical, and adapts the pool cleaner for maximum cleaning action.