Robots: Tiny robot that's smaller than a flea

Scientists have created the smallest ever remote-controlled walking robot and it's in the shape of a crab.

At less than 1mm wide, the tiny robot can bend, twist, crawl, walk, turn and even jump.

Engineers at Northwestern University, US, hope that in the future similar robots could be used to perform tasks in small spaces, including inside the human body.

The team can create all shapes and sizes of robots, so why did they choose a crab?

"The students felt inspired and amused by the sideways crawling motions of tiny crabs. It was a creative whim," says John A Rogers, who led the experimental work.

These remote controlled 3D robots are powered in a different way too.

Engineers built the micro bots using shape memory alloy and glass instead of electronics.

They move by directing a laser beam at the body, which heats it and changes the shape of the bot.

When they cool down and return to their original form they move.

The researchers hope the technology could be used to create future bots for use in machine maintenance and non-invasive surgery - when the treatment does not cut into or enter the body.

To make the 3D robot structure the scientists used a technique they created a few years ago, which was inspired by a children's pop-up book.

Starting with a flat 2D structure, it is then bonded on to a stretchy material which when contracted inwards it pulled the crabs in to create their final 3D form.