Teenager builds an automaton that can detect landmines

When it comes to robots it is difficult to beat Vincent Grace. This year marks his third robot entry to the Esat BT Young Scientist and Technology Exhibition, this time with an automated landmine detector.

Vincent, a 14-year-old third-year student at John Scottus Secondary School, Donnybrook, Dublin, also hopes to set a record by becoming one of the very few who have participated in the exhibition six years running. He is already making plans to submit an entry for 2005 even though two days of judging remain in this year's event.

The landmine detector is a much more sophisticated device than his previous entries. It scuttles about like an insect on six legs, with two servomotors controlling the motion of each leg. It has one circuit board to handle movement, another to control detection and location of landmines and a third to handle infrared communications with a base station.

"It is a walking robot that finds landmines," he explains. It was built using laser-machined bullet-proof plastic brought in from the US but is only a prototype, he adds. It wouldn't set off the mines itself. "It is too light to blow them up."

He looked at several design approaches before going for a relatively simple device, he explained. "It doesn't know where it is, it simply stores information about how far it has moved and where it has found mines."

It downloads this into the base station using infra-red communications, information that the base system then uses to produce a map showing the positions of mines.

It is extremely simple to use. The base station is switched on and then the robot is placed anywhere on the ground. It first walks towards the base station collecting information as it goes, downloads this and is then sent on its way again by the base station.

He did all of the programming that controls exchanges between the circuit boards and map-making. And although he acknowledges it wouldn't detect plastic mines, "Only one per cent of the world's mines are plastic," he observes.

The project prepared by Alan Marrinan (14), of St John Bosco Community College, Kildysart, Co Clare, is by comparison technologically simple but none the less was complex to accomplish. He studied the dispersal of water droplets when a tuning fork is dipped into water.

His science teacher, Mr Leo O'Donoghue, demonstrated wave motion with a tuning fork and water. Alan, a second-year student, decided he wanted to test whether the experiment produced patterns of droplets and how tuning fork frequency might affect the droplet pattern.

He devised a clever series of experiments that helped to show how frequency had a significant effect on the droplets. He did a statistical analysis of droplet patterns on horizontal and vertical grids, marked by dye put into the water.

He also attempted to establish whether droplet dispersal was random and found that it clearly wasn't. Repeated experiments showed that there was a bias in how the droplets were thrown from the beaker.

While the project has few obvious applications in the real world, Alan's project is a good example of scientific problem-solving, involving sustained work over a 10-week period. It has also encouraged him to consider involvement in next year's exhibition.