SCIENCE TODAY:IF YOU HAVE a problem to solve, sometimes it can help to look to nature for inspiration. Scientists at Dublin City University certainly appear to have subscribed to that school of thought – in order to patrol bodies of water for environmental warning signals they have developed a robotic fish, writes CLAIRE O'CONNELL
Named "Wanda" (Wireless Aquatic Navigator for Detection and Analysis), the hand-sized device looks and swims like a fish, complete with swishing tail, but is kitted out with a battery power supply with a built-in camera, a wireless transmitter and customised sensor apparatus as needed.
When you see it you would think of a fish, says Cormac Fay, gesturing to the research prototype he has been developing at DCU over the last year.
When he powers "Wanda" up, the tail starts to swish to and fro. It’s actually a three- layered polypyrrole polymer actuator that bends as charge runs through one side and then the other, and the resulting swishing motion can propel "Wanda" through the water, explains Fay, a research assistant within the Science Foundation Ireland-funded Clarity initiative.
Collaborators at the University of Wollongong in Australia have been working on the tail end, making the actuator more powerful, while Fay has been developing technology in Dublin that allows "Wanda" to monitor and sense conditions in the aquatic environment, such as a change in acidity.
For example in an aquarium you want to keep the fish happy, but the conditions turn alkaline because of ammonia building up unless its cleared, so you’d like to keep an eye on that, he says. To do that you could have these fish following the real fish and keeping an eye on them with the camera and then periodically going on patrol.
That patrol could bring the robotic fish past stationary indicators that relay the current pH of the environment by displaying a particular colour on a chart. If the colour on show indicates a potential problem, "Wanda" could see the indicator chart with the mounted camera, and use video processing software to alert a base system on dry land that action needed to be taken.
The good thing about it is that it is mobile, says Fay, adding that the fish can either swim autonomously or be switched to remote control if needed. So you could have a single fish monitoring a whole pond at little cost. Otherwise you have to have loads of standalone static sensors.
Cost is definitely an issue, he explains. Current robotic devices in use to explore aquatic environments can ring up hefty bills of thousands of Euro, but a "Wanda" fish is considerably lighter on the wallet.
Its not big and the most expensive part is the camera, which is about €50 or €60. They could be mass produced quite cheaply.
And while the current application is for acidity in water, plenty of other possibilities open up if you are smart about your monitoring strategy, notes Prof Dermot Diamond, director of the National Centre for Sensor Research at DCU.
This is just one of the applications, he says. You can adorn it with other types of sensors as well, so as it swims through it can get other types of information.
Possible future development scenarios for the sensor-loaded "Wanda" fish include monitoring the inside of hard-to-access pipes, keeping real-time tabs on aquaculture environments and even remotely sniffing out underwater explosives in the sea, where their low cost makes them dispensable should anything detonate.
But "Wanda" has a way to go before it can withstand a turbulent situation. You would need a pretty still water body at present. It wouldn’t swim up a river, as it’s not at that efficiency stage, says Diamond. But where you don’t have a big flow it would be useful, such as in a tank or a lake in more sheltered areas.
"Wanda" is to be launched at an international conference on functional nanomaterials, which runs today and tomorrow at Dublin City University. See dcu.ie/~ncsr/ for more details