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GCN : March 2013
GCN MARCH 2013 • GCN.COM 23 a large amount of change before things start giving us trouble," he said. "A wall may double in height and we can still of- ten recognize that wall based on the origi- nal imagery that we have of it." SMARTPHONE LIMITS But even as new, sophisticated uses are found as part of environmental monitor- ing, situational awareness and other mo- bile networks, developers are struggling with certain limitations in smartphone technology. On the civilian side, more accurate Global Positioning System signals and synchronization of phones are at the top of the wish list, said Virginia Tech's White. "Right now, on phones, the timing in- formation is inaccurate. By the time you get the time from GPS to the operating system and Java, the timing is completely inaccurate," he said. "There are many, many milliseconds of error. If phones could provide precise timing information from GPS up to the application layer, that would be useful for many of these appli- cations." Finally, despite having GPS receiv- ers, accelerometers, cameras and audio receivers, the sensors in phones are lim- ited. This is partly because manufacturers don't see a market advantage in building in a sensor that, say, measures ozone lev- els. Also, some sensors currently require too much power or cannot be reduced to cellphone size. "Air pollution sensors are electro- chemical sensors, and they use a whole lot of power, so you can't put them in the phone," White explained. "And if you have some kind of external device you'll either need a large battery or it will only work for a few hours. That's definitely a problem." Developers are responding to the cur- rent limitations in two ways --- by build- ing custom sensor devices that include smartphone capabilities and by designing sensor devices that plug into phones. Chris Thompson and his colleagues at SplitSecnd chose the first option. Thomp- son had worked with White at Vander- bilt to develop a smart-phone applica- tion called WreckWatch that would use a smartphone's accelerometer to detect when an accident had occurred and alert an emergency response center. When they moved to commercialize the system, Thompson said, they encountered several issues with the cell phone platform. "A lot of cell phones don't have the same security, don't have the same devel- opment model, and so forth," Thompson said. "With the iPhone, for example, you really can't have an application that runs constantly in the background. Also, we didn't want to limit our customers to have to have a certain smartphone. We found the best way to do that was to just build our own hardware." Other developers have moved to cre- ate sensor devices that plug into phones to take advantage of their capabilities. Sensorcon Inc., for one, is taking advance orders for Sensordrone, a keychain-size device that can measure levels of various gases, temperature, humidity, air pres- sure, infrared temperature and light -- all for under $200. Like most external sensor devices, Sensordrone connects to users' phones via Bluetooth. One thing that has researchers, activ- ists and some in government excited is the potential smartphone sensor net- works offer for community involvement in many types of data collection. "I think there's potential," said EPA's Wayland. "I don't think a lot of them are quite ready for prime time yet but it won't be long before many of these [smart- phone sensor networks] are further en- hanced. And they don't necessarily have to be as good as the regulatory monitors." They could, for instance, be used in a screening mode to alert to a potential problem. "Then if you find something with the screening mode, you can bring in more sophisticated monitors to do more in-depth analysis," Wayland said. According to Tim Dye, senior vice presi- dent at Sonoma Technologies, a Califor- nia-based consulting firm that is working with EPA on its AirNow efforts to collect and make available air-quality data, "the quality of the sensors is not where we want it to be, but that's changing pretty rapidly." He points to AirCasting, a platform de- veloped by HabitatMap, a non-profit en- vironmental health justice organization, to record, map and share health and envi- ronmental data using smartphones. The platform includes an Android application that receives and processes data collected by various sensors, including the AirCast- ing Air Monitor, an under-$200 device that can measure temperature, humidity, carbon monoxide and nitrogen dioxide. Each AirCasting session can capture real-world measurements, annotate the data to tell the story, and share it via CrowdMap. "Once it's on the phone you can start logging the data and share it through the website," Dye said. "And on the website you can crowd source infor- mation." Whether it's a smartphone or handheld device that has cellular capabilites, Bev- eridge from the Environmental Indicators Project is excited by the potential of more portable and affordable sensing devices in the hands of communities. "I think the most powerful thing we're doing," he said, "is teaching community residents to do data gathering, to understand the power of data, the weaknesses of data, and to better understand what science means." • "I think the most powerful thing we're doing is teaching community residents... to understand the power of data." --- BRIAN BEVERIDGE, WOEIP