To Mexican drug cartels, the United States represents both a reliable client as well as a money laundering machine. Every year, U.S. authorities estimate that between $19 and $29 billion of drug proceeds flow from the U.S. down south, over the border. But there is one way to catch smugglers in the act. Chemical engineers in Silicon Valley funded by the Department of Homeland Security say that they’re well on their way to developing a device that could sniff out big wads of illicit cash.
In theory, the device might look like a briefcase and a wand. Passing the wand over someone’s baggage, sensors would then pick up on the faintest whiff of trace gases.
“[The smell] comes from all of the materials it’s made of–all the linens and the inks and the chemicals–and the residue emanates from the surface of the dollar for some years,” explains KWJ Engineering president Joseph Stetter. “We started this project not knowing very much at the beginning and said, ‘Okay, what is the smell of money? And what technologies are available to make sniffers?’”
For several years, Stetter and his team had developed various kinds of chemical sensors for detecting things like carbon monoxide, ozone, and various tools for medical devices. One of their latest innovations came in the form of a tiny, carbon monoxide-sensing chip–one that Stetter stuck on the nose of a stuffed plush panda bear (above) to demonstrate the technology, along with the money sniffer idea, at the latest American Chemical Association meeting. But while animals (especially bears) make superior sniffers, Stetter says, they require lots of upkeep, and communication can be difficult. The technology KWJ is working on can be used 24-7.
“The problem with dogs is that they’re expensive and you have to feed them, even though they can be really cute,” Stetter says. “So if you had an instrument that could mimic the dog’s nose, this could work at border control points to sniff out money.”
Stetter won’t say which gases the tool might detect because it’s proprietary. But one of the biggest challenges of coming up with a machine to replace a dog is the combination of the other contaminants on the money itself. Most dollar bills, as it turns out, have some trace of recreational drugs on them, which can really mess up a machine. Grease, fingerprints, and bits of food can also create extra noise. At the same time, the device has to be tuned so as not to stop someone with a perfectly reasonable amount of cash from crossing the border smoothly.
“You don’t want to stop grandma with 50 bucks in her wallet at the border,” Stetter says.