BACKGROUND: Researchers at Los Alamos National Laboratory are developing a Hands-Off Sampler Gun that would automate the otherwise expensive and time-consuming process of maintaining a proper chain of custody for forensic evidence collected at crime scenes. This will help keep evidence from being mishandled and ensure more credible evidence for jurors. The gun is being marketed initially for forensic biology applications, but could also prove valuable to counter-terrorism efforts.
HOW IT WORKS: When a crime scene investigator locates evidence such as a blood stain, the Hands-Off Sampler Gun collects the sample with its universal sample-media adaptor. Thee investigator never has to touch the sample directly, and thereby avoids the potential for contaminating that sample. Once the sample has been collected, the investigator can testify in court that it was collected properly.
PROVING IT: The investigator will have proof to back up his or her testimony, because an onboard, 3D accelerometer -- a type of sensor that detects force -- records the sampling pattern, which proves that the sample was blotted, wiped or scraped properly. The gun’s force detector measures and records the pressure the investigator applies and compares it to the force necessary for proper collection of, for example, certain biological (DNA) samples. The gun also automatically records the sample’s location with internal Global Positioning System (GPS), measures the ambient temperature and takes a digital picture of the sample being collected. And here is an incorporated barcode reader and audio recorder to further establish proper chain of custody. All this information can be easily downloaded to a desktop computer through standard interfaces.
WHAT ARE MEMS: Accelerometers are an example of microelectro-mechanical systems (MEMS), devices that integrate electronic and moving parts onto a microscopic silicon chip. This integration makes such devices ideal for sensor technology. The term MEMS was coined in the 1980s. A MEMS device is usually only a few micrometers wide; for comparison, a human hair is 50 micrometers wide. Among other everyday applications, MEMS-based sensors are used in cars to detect the sudden motion of a collision and trigger release of the airbag. They are also found in ink-jet printers, blood pressure monitors, and projection display systems.