Frankfurt, Germany ? Let’s face it: you have to be just a little lazy to use a $1,500 robot to vacuum a one-bedroom apartment.

But how sweet it is to stroll barefoot across spotlessly clean wood floors, without having lifted a finger — or, to be more precise, having lifted a finger just once, to turn on the RoboCleaner RC3000.

For three days, the dinner-plate sized robot from German company Alfred Kaercher GmbH randomly crisscrossed the wood floors and kitchen and bathroom tile at my 800-square-foot Frankfurt, Germany, pad, slowly and quietly devouring the dust and dirt that creeps in from the busy street outside.

All I had to do was push the switch and step away.

In a world where essential functions are buried deep in multiple pull-down menus, and where instruction manuals can approach the size of small-town phone books, such user-friendliness soothed my inner technophobe. The robot has just one user interface: the on-off switch.

The base station can be set to different cleaning times or quiet mode, for those who prefer to clean in their sleep.

And that’s it.

Completely on its own, RoboCleaner nosed around chairs, wastebaskets, side tables, an exercise bicycle and the sofa until its dustbin filled up or its battery ran down.

Then it followed an infrared beam to its charging station, docked automatically and dumped its dust into the station’s bin with a whoosh. After recharging for 10-20 minutes, RoboCleaner set out again on another hourlong cleaning jaunt, again unprompted. It kept cleaning, dumping and recharging for eight hours until being turned off for the night.

Phil Mass demonstrates the Roomba, a robotic vacuum cleaner that he developed for iRobot. The Roomba can self-vacuum any sized or shaped room with the aid of sensors that allow it to detect obstacles and hazards.

It even climbed right up onto the thick pile rug in my bathroom and scoured its fibers, although the machine isn’t near as effective on deep carpets as is on, say, thin wall-to-wall.

User-friendly device

Easy use was a chief goal, says Frank Schad, spokesman for Kaercher, located in the town of Winnenden just outside Stuttgart in southern Germany. “We wanted to make a friendly robot,” Schad said. “You just plug it in and start. You don’t have to learn a big manual.”

The company began selling the machine in Europe earlier this year; it’s due in the United States after Nov. 1, priced at $1,499 through the Frontgate.com Internet and catalog retailer.

RoboCleaner works by feeling its way around. When its shell bumps a wall or another obstacle, its processor brain instructs it to spin and continue in a straight line until it hits something else.

The angle of the turns is random, so the device might vacuum the same spot two or three times, or wander to other rooms before finishing the job where it started.

That means it’s slow, and of little use for quickly attacking isolated spills. At my place, it took a good six hours to finish the whole apartment.

However, it’s the robot’s time, not mine.

I went out to run errands and left the machine alone several times without its getting stuck, even in the tangle of computer cables under my desk.

Another limitation is its inability to get all the way into corners. The company says people should use the machine for everyday maintenance cleaning and do a more thorough vacuuming every now and then.

Susanne Kurtenbach, employee of Swedish company Electrolux, presents the Trilobite, a vacuum robot cleaner, which is navigated by ultrasound.

And if you live on more than one floor, you have to bring it up and down stairs. It has a stairs detector that keeps it from tumbling down if left alone.

Those are drawbacks common to RoboCleaner and the other robot vacuums already on the market, which include the Roomba from U.S. firm iRobotics, and the Trilobite from Sweden’s Electrolux.

Roomba includes a virtual wall light beam to confine its wanderings, while Trilobite has magnetic strips that need to be stuck to the floor.

And, unlike a human, they’ll all vacuum up a diamond earring just like they do a peanut shell. It’s all the same to a robot.

Product comparison

RoboCleaner has advantages and disadvantages compared to the competition, the Roomba and Trilobite, which I also tested.

RoboCleaner is far more expensive than the $200 Roomba — but the Roomba I tested has to be picked up and moved from room to room, and won’t empty itself — in other words, it requires some minimal work and initiative from a human. A new model can navigate multiple rooms.

Roomba, which has a side brush that helps it clean close to walls and farther into corners, bustles about a bit faster and can make short work of a room in a half an hour or less. And its lower profile enabled it to clean under my sofa where RoboCleaner wouldn’t quite fit.

Electrolux’s Trilobite, which sells in Europe for about $1,700, and isn’t available in the United States, feels like a more solidly built device, with a powerful vacuum motor and a sleek, red metal body.

Trilobite actually can see obstacles with ultrasound sensors, so it’s less likely to jostle something off a side table. And its powerful vacuum likely gets a bit more dirt — although it makes tons more noise than RoboCleaner.

RoboCleaner, on the other hand, is so quiet that one can engage undisturbed in other important household chores, such as reading or watching television. And its sensors let it know when it has run across heavier amounts of dirt, making it back up and re-vacuum.

Eventually, I had to pack it up and send it back. My floors are still clean — but my ordinary, nonrobotic vacuum makes me lift all 10 fingers to make that so.