Roboticist Zack Butler has developed a software to move virtual fences, controlled by Wi-Fi, and managed from a server ‘back at the ranch’.

The virtual fence is a set of GPS co-ordinates to be downloaded to the collar of the cow. If the animal gets too close to the fence co-ordinates, the collar makes a noise (roaring tigers, barking dogs or hissing snakes), or give the cow an electric shock. When the fence moves, it herds the cattle with it.

The prototype collars are equipped with a PDA, a GPS unit and a loudspeaker. They have built in Wi-Fi networking cards, and communicate with the controlling server thanks to a 802.11b base station located in the field.

More in New Scientist, via The Register.