Mar 18, 2015A decade ago at the Argonne National Laboratory, a nonprofit research facility operated by the University of Chicago for the U.S. Department of Energy (DOE), senior computer scientist Pete Beckman began co-teaching a class on wireless sensors at the university, and also experimenting with wireless sensor networks at the Lab. That research evolved over time. Initially, it was used to track environmental conditions in data centers. Then, Beckman says, a growing number of scientists and researchers within Argonne and across the DOE began finding applications for wireless sensors, "so the Lab said, 'Let's see if there is a way to build a reusable, deployable platform that could then be used for a variety of projects.'"
That work has evolved into a platform called Waggle, named after the figure-eight dance that honeybees perform to communicate the location of nectar, pollen and water sources to other bees in a hive. "I think of bees as the very first wireless sensors," Beckman says. "They go out, collect data, and come back and report."
Waggle is now being deployed in a fast-growing list of projects in which sensors are utilized to track environmental factors in both urban and rural or agricultural environments.
The Array of Things project is being led by the Urban Center for Computation and Data at the Computation Institute, a joint initiative of Argonne National Laboratory and the University of Chicago. Its partners include a long list of academic institutions around the United States, as well as technical consultancy from industry partners including Cisco, Schneider Electric, Intel, Qualcomm, Motorola Solutions and Zebra Technologies. Its mission is to collect real-time data regarding the city's environment, infrastructure and activity, for both research and public use.
The city of Chicago hopes the Array of Things project, which launched last year with the deployment of 50 nodes, will enable municipal planners not only to track environmental factors such as air quality and noise, but also, by additionally monitoring the movements of pedestrians (by counting unique but anonymous Bluetooth and Wi-Fi radio signatures), to better understand how the city's natural and built environments impact its livability. The project's goal is that residents, software developers, scientists and policymakers will all join together to analyze the collected data, in order to make the city a healthier, more energy-efficient place to live.
Ecosystem Spectroscopy (EcoSpec), a project led by Yuki Hamada, an Argonne scientist specializing in remote sensing, plans to deploy Waggle nodes outfitted with specialized hyperspectral cameras to measure the reflectivity or absorption of invisible light wavelengths (well outside the bands that humans can see) by plants and soil. The goal of this research is to track, for example, photosynthesis or carbon sequestration as a means of studying ecosystem dynamics, and ultimately to improve climate forecasting. An urban climate modeling project that Argonne computation computer scientist Robert Jacobsen is leading, and which seeks to better understand how cities impact climate and weather models, through heat islands and other effects, will also employ the Waggle platform.
The platform is based on nodes that can accommodate a wide range of sensors. The nodes communicate to the cloud (or "beehive," in Waggle parlance) via various technologies, including wired Ethernet, Wi-Fi or a cellular network via a subscriber identity module (SIM) card. In the cloud, the data transmitted by the nodes is further processed and is then sent directly to Internet-based applications, or to another cloud-based server for analysis. The Secure Sockets Layer (SSL) protocol is used to secure data transmissions sent via the Waggle network.
Each node contains at least two microcontrollers, which run Linux-based open-source software developed at Argonne by Beckman and his colleagues. The software is designed not only to manage and collect data from the sensors attached to the node, but also to perform some processing. Thus, the software was developed as a move away from what Beckman calls "the Internet of Dumb Things," wherein sensors are deployed to simply collect and transmit data, and not carry out any data processing.
"I don't mean to sound pejorative, but... we really want computing to happen where the sensors are placed," Beckman explains. "A lot of IoT [devices] now are just data loggers. Our interest, as computer scientists, is computing at the edges."
In an Argonne Laboratory article, Rajesh Sankaran, a computer scientist and one of Beckman's Waggle teammates, explained that integrating processing power into the Waggle nodes means that researchers who are not computer scientists can use the platform easily, programming it to respond only to specific parameters, such as temperature or sounds. This, he noted, makes the nodes essentially plug-and-play, while vastly reducing the amount of unneeded data that is collected.
Beckman cites two very different examples of how this in-node processing power can be used. "Suppose you wanted to know what parts of the city have the worst problems [noise pollution] from people honking their horns," he states. "The bad approach would be to [collect and] send all of the audio collected at each node site to a central place. That would be a massive amount of data. A smarter way is to write a program that detects horn honks, calculates how many horns are honking per minute, etc.," and then transmit just this information to the cloud, not the audio data itself.
In a different example—though one also based on tracking sounds—Beckman says environmental scientists at a forest preserve in Illinois' Cook County are interested in using Waggle to track a specific frog species that vocalizes for only a few days each year. Rather than continuously recording throughout the weeks or months when the frog might vocalize, Beckman explains, the nodes would be deployed with "a sensor that knows what the vocalization sounds like and automatically sends an alert to staff when the sound is detected. That's smart IoT, where computing is happening at the edges."
The Waggle nodes are not set up to communicate to each other through a mesh topography, Beckman says. However, he notes, they could be configured to do so in the future. The nodes are line-powered, but Beckman reports that the Waggle team is currently working on a battery-powered iteration, as well as one that could receive power through a solar panel or other energy source.
