HOW CAN a trundling robot armed with a battery charger help to fight bioterrorism? Simple. It will wheel about keeping networks of anthrax sensors fully charged, and ready to raise the alarm should they catch a whiff of the deadly organism.
In the wake of last year鈥檚 anthrax attacks, companies are keen to develop cheap wireless sensor networks that can monitor air in postal sorting offices and government buildings for signs of biowarfare agents. But there is a stumbling block: how do you keep the battery-operated sensors fully powered and calibrated without having to hire armies of technicians?
Enter the caretaker robot, under development at Intel鈥檚 research labs and at the University of Washington in Seattle: it鈥檚 designed to maintain the sensors and perform basic troubleshooting. 鈥淲e wanted to see what it would take to make a sensor network completely autonomous,鈥� says Gaetano Borriello, director of Intel Research, Seattle.
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But not having a post office full of anthrax sensors to hand, Intel has found the next best thing 鈥� the robots are looking after a bunch of house plants dotted around a large room. The plants bristle with sensors that need maintenance.
Using a wireless computer network, Intel has arranged for an off-the-shelf wheeled robot, about the size of a vacuum cleaner, to communicate with an array of sensors that monitor the moisture levels, temperature and light levels around six pot plants.
When moisture levels drop, the sensor alerts the robot, who trundles over and waters it. And once a week, it also recharges the batteries that power the sensors using an inductive charging coil.
Part of the robot鈥檚 routine involves comparing the outputs of light, temperature and moisture sensors in the plant pots with those of ideal sensors on the robot 鈥� and correcting any that have gone awry.
When it runs low on power, the droid rolls over to its own maintenance bay for a recharge.
Borriello will tell delegates to this week鈥檚 conference on ubiquitous computing in Gothenberg, Sweden, that you don鈥檛 need to program the robot with a plan of the plant locations. It simply roams around until its camera recognises a standard terracotta plant pot.
It鈥檚 programmed to roll into each plant pot very gently. When an accelerometer on the pot鈥檚 sensor picks up the bump, it sends a radio message to the robot. 鈥淚t鈥檚 like the robot鈥檚 asking, 鈥淚s this a plant?鈥� and the sensor is saying 鈥淵es.鈥� It then records where the plant is for future reference. That means you can add, move or remove plants from a network without having to update the robot each time because it finds the plants itself.
John Byers, who has worked on ways to save power in wireless sensor networks at Boston University in Massachusetts, says using a robot to maintain a sensor network makes sense in a potentially hazardous environment, such as a suspect sorting office, where it could reduce the number of visits a human engineer would have to make.