'Talking' robofish set to do undersea environmental duties

Washington, June 18 : University of Washington researchers have equipped three fish-like robots, each 20 inches long and weighing just over six pounds, with acoustic transmitters to communicate wirelessly with one another while underwater.

Kristi Morgansen believes that robofish based on her model may someday help monitor the migrations of large mammals and the diffusion of environmental pollutants.

"When the robofish are underwater we can't communicate with them. They have to be very independent," Discovery News quoted her as saying.

She has revealed her robots swim like regular fish by using a flapping tail rather than rotating propeller.

Just as actual fish communicate using an organ called the lateral line, which detects movement and vibration in the water via waves of physical pressure or sound waves, Morgansen's robots communicate by using acoustic modems that ping sound waves to each other.

The researcher has also equipped the robofish with pressure sensors to monitor depth, and a three-dimensional compass, all powered by nickel-metal hydride rechargeable batteries.

Morgansen has revealed that the three robots are currently not suitable for tests in the ocean.

She says that the next batch of robofish, expected to arrive next year, should venture into the waters of Puget Sound, where they are expected to be able to track anything from large whales to microscopic environmental contaminants.

According to her, all that her team will have to do is to walk to the beach and drop the robofish in the water.

Microprocessors and sensors installed in the robots will perform the rest of the task, she adds.

The robofish will resurface to communicate with home base using a satellite link in every 20 minutes or so, and upload their data to the researchers and download any additional instructions.

Morgansen says that the robofish may operate for about six months at a time before being picked up by researchers in a boat.

Drexel University researcher James Tangorra, who studies bio-inspired designs, believes that such batches of robofish may help scientists track schools of fish.

"Fish-like propulsion might be more efficient, faster, and silent, allowing us to operate next to animals," said Tangorra.

ANI