RFID tags are already being used to track groceries and pharmaceuticals, but the Japanese Ministry of Internal Affairs and Communications now wants to use the technology to help find disaster survivors. The ministry said that it intends to sprinkle disaster areas with RFID-tagged sensors that will form a mesh network to detect heat and vibration.

While RFID tags themselves are small, these sensors will be several centimeters large (wide and high). Thousands of sensors will be needed to cover a disaster area: According to the ministry, it will take about 10,000 sensors to cover a large airport.

Given Japan's high earthquake risk, the system seems to be a no-brainer. Earthquakes often knock out communications, not just from the damage itself, but from people overloading the phone networks. In addition, fires and damage to roads could make driving into the area very dangerous. It's expected that the sensors would be sprinkled by helicopters or small fixed-wing planes.

The research related to this project is expected to be completed in 2007.