When the earthquake and tsunami struck northern Japan last March, the home of Shoji Tanaka was spared any major damage. But he worked as a volunteer in the disaster zone, supplying clothing and helping.

The experience provided a creative incentive for Mr. Tanaka, an inventor who is president of Cosmo Power, a Japanese engineering company: It "spurred me to work hard to complete Noah," he says.

"Noah" is Mr. Tanaka's version of a modern-day ark, and his answer to the possibility of another tsunami. A bright yellow globe 1.2 meters in diameter, Noah is made of fiber-reinforced plastic that can withstand blows from a sledgehammer. Up to four people can fit inside the pod, which rights itself in water and can survive a drop of 10 meters.

Mr. Tanaka designed his pod as a "temporary refuge," he said, so that in a tsunami, people can get inside and be carried by the water for one or two hours, until help arrives. Small air ducts make it possible to breathe, and there is a small window to see outside.

The product retails for about $3,800. Mr. Tanaka says he has orders from Japanese customers for more than 1,000 pods.

Yoshiyuki Sankai, an engineering professor at University of Tsukuba near Tokyo, was inspired to update one of his inventions after the tsunami. He transformed his Hybrid Assistive Limb, or HAL - a lower-body, robotic exoskeleton - so it could assist people working at radiation sites. The original HAL, introduced in 2008, helps patients who can't walk by monitoring the signals sent from their brains to their muscles. Sensors in HAL pick up the signals and then, essentially, walk for the person.

Dr. Sankai was already working on other uses for HAL when he received a call last summer from a company involved in the cleanup of the Fukushima Daiichi nuclear power plant, the site of the nuclear disaster resulting from the tsunami. Could HAL assist workers who had to wear incredibly heavy, anti-radiation tungsten vests at the site?

In the new model, an upper-body frame supports the tungsten plates, which can weigh up to 60 kilograms.

The tsunami is not the only disaster to inspire tinkering. After witnessing the effects of the earthquake and tsunami on Thailand in late 2004, Hidei Kimura was disturbed by the communications breakdown in the area.

As chief executive of Burton Inc., a Japanese company that specializes in 3-D displays, Mr. Kimura had an idea: "If textual information could be drawn in midair" - without a need for a screen - "far more people could see it and have access to valuable information," he says.

The result is Aerial 3D, which uses laser beams to create text out of tiny, luminous dots that can be used to broadcast messages in the air. Practical use aside, he says, people are intrigued by his creation on a less serious level: "They say it's just like 'Star Wars.'"

The New York Times