Machine Design

Scanning for Ideas: Building a Better Rat Trap

The Wise Trap from Wisecon, a Danish firm (, takes care of rat problems in sewage and drainage pipes without using poisons. It consists of a trap and a controller. The controller hangs from the lip of a manhole entryway to the pipes. It contains a camera, the Wisecam 1, that lets users determine if there is a rat-infestation problem and when the problem has been taken care of. It can also be used for other sewage-pipe surveillance tasks.

The camera illuminates the bottom of the well with an IR light and a memory card stores recorded images for three days. The battery-powered trap itself is positioned at the bottom of the well. A screw-together installation pole lets users position the trap and expand a collar that locks it into place.

Once secured in the pipe, sensors search for movement and heat, criteria that indicates a rat is in the trap. The controller signals an actuator that rapidly lowers a series of spears that kill the rat, and are then retracted. The animal is dispatched rapidly and humanely, according to the manufacturer. Sewage water flushes the dead rat away and the trap is ready for another victim.

Data from the trap is transmitted to users via SMS/GSM modem. That data includes notification that no rats have been trapped in a specified period, indicating the trap can be removed and relocated. Data also reveals when there are operational stops, overflow in the pipes, and low-battery levels.

Edited by Stephen J. Mraz

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