Try this in your home: a pint-size companion that recognizes your face and follows you around, sings to itself, pouts when ignored and knows how to operate all the electrical appliances.

Sounds like a kid. But this is a robot named R-100, the latest creation from robotics-crazy Japan.

NEC Corp. researchers have soldered together this prototype of what they call a "personal assistant" robot. They say it is a new step in technology, even if it seems awfully familiar: It's R2-D2 of "Star Wars"; the automated "Rosie" for "The Jetsons"; the "Robby" for Dr. Morbius on the "Forbidden Planet."

"These robots are common in sci-fi, but everyone thinks they are just a dream. We thought maybe it was time to start working on this dream," said Yoshihiro Fujita, project manager of the robot in NEC's research "incubation center."

The result is an 18-inch-high, 17-pound robot that looks like a compact vacuum cleaner with eyes. And a mouth. A busy mouth, at that: Its creators have given R-100 a childlike voice and an impish "personality."

It responds to pats on the head, but provide too many and it gets mad. If you ignore it too long, it will turn its back on you. It can sound cheerfully helpful, or put-upon as though you've made too many demands. It whines if it senses it is abandoned.

Give it nothing to do, and it might launch itself around in circles, singing a merry nonsense tune as though it's bored.

"You could make it without a personality, but that's a personality in itself--just dull," Fujita said. "We wanted to make something that you would want to live with, something that would be helpful, but like a member of the family."

R-100 is entertaining, but its real purpose is to operate today's electronically "smart" homes. On voice instructions, R-100 will adjust the heat, air conditioning and lights, turn on the television and pick whatever channel you want.

It also connects wirelessly to the Internet. You sit in your favorite chair and call out a Web site, and R-100 brings it up on the TV screen. You can dictate an e-mail, which R-100 sends instantly. It announces when you get one back, and will read it or display it on the TV. You can leave a recorded video message with R-100 to deliver to a family member when the robot next sees that person.

"Digital devices now do almost everything except make dinner for you, and maybe even that. But they are often not very friendly devices," said Aston Bridgman, a spokesman for NEC. "This robot is to operate all those complicated machines in your home, and do it with a friendly personality."

The robot is not ready for sale. It still needs about two years of work, according to Fujita. For one thing, some of its functions are still being done by an outside computer and transmitted to R-100. Those need to be miniaturized and put into the robot.

Much of the technology in R-100 has already been designed for robotics. The NEC designers say they integrated it into a useful package and added a new wrinkle--visual recognition. The robot is the first capable of scanning a person's face into its memory. It then can "recognize" that person and react differently to each individual.

The robot also responds to "touch"--pats on its plastic dome--and has voice recognition. It understands about 300 phrases and can say about 100.

One problem for Americans: R-100 speaks only Japanese.

"I suppose that's something we could work out," Fujita said.

CAPTION: R-100, the newly developed robot from NEC Corp., responds to pats on its domed head, understands about 300 Japanese phrases and operates appliances in today's homes.