Low-cost robot to locate land mines

With this statistic in mind, Johns Hopkins Applied Physics Laboratory physicist Carl Nelson posed a challenge: Develop a device to transport new sensors he created to detect land mines in thick vegetation. Four engineering students at Johns Hopkins University rose to the challenge. They designed and built a remote-controlled robot to find land mines and mark them with paint. The robot takes the form of a two-piece vehicle that rolls on tank-type threads. The front portion carries two cordless drill motors for locomotion running from a lead-acid battery. On top of the drive segment is a color video camera, which lets the operator see what the robot encounters.

The drive segment attaches to a second unit housing a simple metal detection coil from an off-the-shelf detector. The rear segment also holds a small storage tank and a spray-paint nozzle to mark the spot when a potential mine is located. The paint tank carries enough for about 40 shots.

An operator uses a battery-powered controller with a joystick to steer the vehicle. The controller features a small video screen displaying real-time images from the camera. When metal is detected, a beep comes over a speaker on the controller or via headphones worn by the operator. The camera transmits video up to 100 ft and the robot's movement can be controlled from a distance of about 500 ft.

The robot is mostly plastic and other nonmetal parts to cut costs, weight, and false positive readings from the mine detector.

The students worked within a budget of $8,000, spending about $5,000 to design and build the prototype. They estimate the robot could be mass-produced for $1,000 or less, not including the cost of more-sophisticated detection sensors. Explosive-detection researchers are considering the prototype as a model for a low-cost robot to prevent mine-related deaths and injuries.