Matt Walker is Robot Dad. Credit:Matt Walker From his home in San Jose, California — where he lives with his current wife and seven-month-old son Jack — Matt logs into the RambleBot that lives at his ex wife's house 11,410 kilometres away in Brisbane, Australia, and hangs out with his sons, controlling the robot with an app and talking via Skype. He's done this every other day for the last three years. The robot has a big battery which lasts about two days. The smartphone battery runs out faster, so Matt adds a battery extender case. When the RambleBot is plugged in, it will charge the phone. Matt acknowledges the unusual set-up may have its critics because it's essentially parenting at a distance. "What's he [my son] going to tell his psychoanalyst in the future — my father was a tiny little robot?" Matt jokes.

Matt Walker Skyping his son Jarvis as the RambleBot. Credit:Matt Walker "Telepresence will never be as good as being there in real life. "However it's actually easier to play hide and seek ... I'm able to hide in the most obscure corners and under beds!" Clockwise from top: Matt Walker with his three sons Jarvis, Maxi and Jack. Credit:Matt Walker Most important is that the kids love it.

"It's robots! They don't think about how weird it is, they just think it's cool," he says. Anyone who's tried to Skype young kids will know they can easily get bored and walk away from a computer. The kids' mum, Sharon, says having Matt visit as a robot is much easier. "At first I was like, 'What the hell?!' but it's actually pretty cool," she says. "It helps him [Matt] have control of the view and everything he's doing, and it also means I don't have to be there every second." Matt says having a robot his kids can pester and interact with keeps them engaged and entertained. After a while you begin to feel like you're right there in the room with them, he says.

And something remarkable happened with Maxi. Maxi has autism, and doesn't normally look his parents in the eye. But when Matt visits as a robot, Maxi looks right at the smartphone screen where his father's face is. Sharon says the robot didn't necessarily make divorce easier, but the fact Matt went to so much trouble to build it showed he wanted to spend time with the kids even though he moved away. "[The robot] wouldn't work any better than anything else in a situation where there's a lot of bitterness," she says. "You have to be open to making it work, but really, when the motivation of both parents is the children's happiness, then usually you can get to that place." Matt still flies back to Australia to see Jarvis and Maxi in person during school holidays. When he's in Australia, he visits Jack back in California as a robot.

RambleBot takes off Matt got the idea to build a smartphone-enabled telepresence robot after he used the Botiful, a compact bot on wheels which is no longer in production. Matt thought the Botiful had some drawbacks, such as only being able to roam on smooth surfaces. Matt now makes RambleBots by hand in his own home and sells them for $US199 ($US248 with an arm gripper). He also has a miniature version called a PuckBot which sells for $US59. It fits in a handbag and runs purely off a 5V smartphone battery. There are other telepresence robots on the market today, but most of them are way beyond the price range of an average lonely parent. There's the Teleporter, and the Segway-inspired AnyBot, which sell for about $US15,000 ($20,587) each; the Double robot, at $US3000; and the Beam for $US2000 – still 10 times the price of the RambleBot.