How-To: Tell Mammoth Ivory from Elephant Ivory

Whatever the larger implications of the mammoth ivory trade may be, it has created a practical forensic problem for law enforcement. Buying mammoth ivory is, generally, legal, while buying elephant ivory, generally, is not. But when you’re a customs official staring at a crate full of tusks, how do you know which is which?

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In the Maker Shed: SIM Card Reader Writer Kit

Ever wonder what kind of information gets stored on your cell phone’s SIM card? Find out with the SIM Card Reader / Writer Kit from the Maker Shed! Build the kit, then use the accompanying software to read and write from the card, to back up stored SIM card data, recover deleted SMS text messages and phone contacts, examine the last 10 phone numbers dialed, and more. Also works on some smart cards.

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3D Models from Photographs

Photogrammetry has been with us for as long as we’ve had cameras. Autodesk has taken it to its logical next step with Project Photofly. Using a standard point and shoot camera you can take a series of photos of an object, upload them to the cloud, and get a detailed 3D model back that can be manipulated with standard design software.

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The Truth Meter: Don’t Sweat It

[youtube] When you feel nervous, excited, surprised, or otherwise aroused, you experience galvanic skin response (GSR). Your sweat glands, in responses to adrenaline and other hormones, start to release micro pulses of sweat. GSR is one component of polygraph tests because it’s an indicator of how nervous a question makes you feel. The increase […]

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How-To for Secret Agents: Invisible Ink Printer Mod

[youtube] Make: Online readers who are secret agents—or secret agent wannabes—will love this project, which comes to us from MAKE Volume 16. By replacing the ink in a color inkjet cartridge with concentrated lemon juice, you can print with invisible ink. The secret message is revealed by spraying or wiping the paper with iodine […]

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You can be identified by the germs you leave behind

A study by Noah Fierer and co-workers at the University of Colorado at Boulder suggests that the mix of bacterial flora each of us leaves behind on, say, our computer keyboard or mouse, may be sufficiently unique to identify us:

“Each one of us leaves a unique trail of bugs behind as we travel through our daily lives,” said Fierer, an assistant professor in CU-Boulder’s ecology and evolutionary biology department. “While this project is still in it’s preliminary stages, we think the technique could eventually become a valuable new item in the toolbox of forensic scientists.”
The study was published March 15 in the Proceedings of the National Academy of Sciences. Co-authors on the PNAS study included Christian Lauber and Nick Zhou of CU-Boulder’s Cooperative Institute for Research in Environmental Sciences, or CIRES, Daniel McDonald of CU-Boulder’s department of chemistry and biochemistry, Stanford University Postdoctoral Researcher Elizabeth Costello and CU-Boulder chemistry and biochemistry Assistant Professor Rob Knight.

Using powerful gene-sequencing techniques, the team swabbed bacterial DNA from individual keys on three personal computers and matched them up to bacteria on the fingertips of keyboard owners, comparing the results to swabs taken from other keyboards never touched by the subjects. The bacterial DNA from the keys matched much more closely to bacteria of keyboard owners than to bacterial samples taken from random fingertips and from other keyboards, Fierer said.

Here’s the abstract for Fierer’s paper at PNAS.

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