Lawrence Livermore National Laboratory (LLNL) is working on a PDA that can detect nuclear materials.

The device, known as RadNet, is designed to make calls, surf the Web, act as a Personal Digital Assistant, pinpoint locations with Global Positioning System technology and sniff out nuclear materials with a cutting-edge sensor. It is one of several national security projects being worked on at Lawrence Livermore National Laboratory.

The detector may eventually be built into a large assortment of vehicles and it could report detected radiation and a GPS-determined position automatically.

Livermore's Simon Labov, director of the lab's new radiation detection center, sees RadNet phones in the hands of police, firefighters and U.S. Customs agents. One day, though, Labov imagines the gizmos will be built into taxis, rental cars and trucks.

The effect would be to create a large network of roaming sensors over a large area.

“In effect, all of the phones operating at any time are part of one large detector that is spread out throughout an entire geographic area,” Labov explained.

The deployed detectors would all report back to a central database where patterns of radiation changes could be detected and tracked.

With continuous monitoring and data collection, the system can look for patterns of radioactivity in a given area and detect changes that indicate a hazardous condition, he added.

A system of this sort wouldn't require human carriers to be looking at radiation detectors continuously. A microprocessor could automatically continuously read the radiation sensor in each device and it could automatically call in any reading it encountered that was above some threshold level.

Any type of sensor that can be paired with a microprocessor to look for anomalous sensor readings could be deployed in a similar fashion. A variety of chemical and biological agent detectors will surely be developed that can operate for long periods of time without the need to resupply reagents. Then mobile networks of automated biological and chemical terrorism detectors will be deployed along with the nuclear materials detectors.

But there are ways that chemical detectors could be used for more conventional law enforcement purposes. Consider how dogs can detect the smell of a person and track that smell. DNA samples are now widely collected from criminals. If some aspects of a person's scent are stable thru a period of years then it is not hard to imagine that some day scrapings of skin and sweat will be taken from each felon to be analysed to build a chemical signature of that person's scent. Then when chemical sensing technology becomes sufficiently advanced sensors that can detect specific chemical scent signatures could be deployed to continuously analyse the air in public areas. Wanted criminals could be identified by their scent as they pass a public detector. One could easily imagine banks allowing the deployment of such detectors so that the chemical signatures of bank robbers could be recorded along with video recordings.