Another Trick for Your Cell Phone: Smelling
The porous silicon chip is used in sensing of pollutants and environmental toxins.
CREDIT: Adrian Garcia Sega, UCSD
Who needs a bloodhound – or even a nose?
The U.S. Department of Homeland Security (DHS) is hoping that soon your cell phone will sniff out poisonous gases. It’s funding three companies to create a small chip – about the size of a dime – that would sit inside of cell phones and alert users to potentially deadly smells.
Michael Sailor, whose research team at the University of California, San Diego works for Rhevision Technology, Inc. to create the chip, says the chips are most useful for first responders or other emergency workers. Firefighters and police could track the location of, say, a noxious cloud in a subway, by monitoring GPS signals from the passengers’ cell phones. They could then use the information to better coordinate a response.
“It’s a laudable goal when you think of it like that,” Sailor said.
The technology is similar to that of a computer chip. Scientists start with a silicon wafer, which they fill with billions of nano-sized holes that reflect different colors depending on their size. If poisonous gas molecule such as sarin enters the hole, it displaces the air inside it, and causes the color that the hole reflects to change.
Tiny lenses affixed to a cell phone's camera can be used to monitor these color changes. If the lenses spot a color that is related to poison, they will trigger an alert system on the cell phone. Sailor’s team is a sub-contractor to Rhevision, a startup in San Diego that invented the miniature tunable camera lens, which makes the lenses. So far the chips have successfully detected sarin gas, methyl salicylate – a compound used to simulate mustard gas – and toluene, a gasoline additive, among others.
The DHS's science and technology division is also funding similar projects at NASA and Qualcomm. Stephen Dennis, Project Manager for the Science & Technology Directorate of the Department of Homeland Security, says the mission of the DHS – to protect the homeland – can be revolutionized with the help of the cell phone.
“It’s the most ubiquitous that you could possibly make chemical sensing,” Dennis told TechNewsDaily.
To be sure, there are several hurdles to this goal. For example, many cell phone companies are leery of more features being added on to an already packed gadget, Sailor said.
And what about the price? Right now the chips cost about a quarter to make. In volume that would drop to approximately a few cents, but cell phone companies are always fighting for lower price points. And then there’s the consumer, who may be suspicious of a device that’s capable of tracking their location.
As a next step, the DHS hopes to have 40-80 different prototypes within 18 months, which will be installed in new phones. The prototypes will focus on building a network system that would piggyback on networks that emergency response services already use.