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What is Chicago’s Array of Things Initiative?

The project to collect real-time data on Chicago's environment and urban activity launched in 2016 and continues to evolve.

This story was originally published on Data-Smart City Solutions

The 606, Chicago’s rails-to-trails project that stretches for 4.2 miles on the city’s northwest side, has been popular with residents and visitors ever since its launch last year. The trail recently added a new art installation, Blue Sky, that will greet visitors over the next five years with an array of lights and colors. Less noticed, but no less important, will be another array on display near the trail: a sensor node from Chicago’s Array of Things initiative.

If you’re a frequent reader of all things civic tech, then you may have already come across the Array of Things (AoT). Launched in 2016, the project, which consists of a network of sensor boxes mounted on light posts, has now begun collecting a host of real-time data on Chicago’s environmental surroundings and urban activity. After installing a small number of sensors downtown and elsewhere in 2016, Chicago is now adding additional sensors across the city and the city’s data portal currently lists locations for all of AoT’s active and yet-to-be installed sensors. Next year, data collected from AoT will be accessible online, providing valuable information for researchers, urban planners, and the general public. 

AoT’s public engagement campaign has been picking up steam as well, with a recent community event held this fall. As a non-proprietary project, AoT is being implemented as a tool to improve not just urban planning and sustainability efforts, but quality of life for residents and communities. To engage with the public, project leaders have held meetings and workshops to build relationships with residents and identify community priorities. Those priorities, which vary from community to community, could range from monitoring traffic congestion around specific intersections to addressing air quality concerns at local parks and schoolyards.

The AoT project is a leading example of how new technology—and the Internet of Things (IoT) in particular—is transforming efforts for sustainable urban growth and “smart” city planning. AoT’s truly multi-dimensional character sets it apart from other smart city efforts: complementing environmental sensor data collection, the initiative includes educational programming, community outreach, and R&D opportunities for academics, startups, corporations, and other organizations that could stand to benefit.

Launching a project like AoT, of course, isn’t as simple as installing sensor nodes and flipping on a switch. AoT has been in the works for years, and its recent launch marks a milestone event for its developers, the City of Chicago, and smart city technologies. AoT has frequently appeared in the press – yet often, coverage loses sight of the many facets of this unique project. How did AoT get to where it is today? What is the project’s significance outside of Chicago? What are AoT’s implications for cities? Consider this article as your primer for all things AoT.

What is the Array of Things?

According to its official website, AoT is “an urban sensing project, a network of interactive, modular sensor boxes that will be installed around Chicago to collect real-time data on the city’s environment, infrastructure, and activity for research and public use. It will essentially serve as a ‘fitness tracker’ for the city, measuring factors that impact livability in Chicago such as climate, air quality and noise.”

While sensors are not uncommon to cities, AoT is the first project of this scale and level of specificity. AoT’s sensor boxes – or nodes – consist of protective shields with up to 15 sensors, a computer, two cameras, a microphone, and even a cooling fan. When fully implemented, AoT will consist of 500 of those sensor boxes across the city.  


 A sample "node" from the Array of Things project. Source: UrbanCCD.

In August 2016, the AoT team installed the first of these current nodes on two light posts on Chicago’s near southwest side; in October, they then activated those nodes. As of this writing, there are 42 nodes in strategic locations citywide, as seen in the map below.  


 Source: Charlie Catlett, Argonne Labs

As 2018 approaches, Chicago plans to add more new nodes in locations across the city.

Who’s behind the project?

AoT is managed by a wide range of partners working together to provide a truly comprehensive program that positively benefits all walks of urban life.

The project is led by researchers from the Urban Center for Computation and Data (UrbanCCD) at the Computation Institute, a joint initiative of Argonne National Laboratory and the University of Chicago under the direction of Argonne computer scientist Charlie Catlett. Efforts to develop the Waggle platform— the software and hardware that powers the Array of Things Project— have been led by Argonne Institute of Science and Engineering Co-Director Pete Beckman. Catlett, Beckman, and their associates are the minds behind the technical aspects of the project.

First publicly announced in June of 2014, AoT has been supported by more than $1 million in internal research funding from Argonne. In the fall of 2015, the project was able to really pick up steam following the reception of a $3.1 million grant from the National Science Foundation

AoT has been executed in partnership with the City of Chicago, which has been installing nodes onto light posts across the city via its Department of Transportation. The City’s lead agency on the project, the Department of Innovation and Technology (DoIT), manages Chicago’s aforementioned data portal, which will house AoT data for the public. Chicago CIO and DoIT Commissioner Danielle DuMerer, as well as her predecessor Brenna Berman, have been driving forces for the project. Berman’s role in launching AoT in particular was detailed in her 2016 interview with Data-Smart City Solutions.

Civic organization Smart Chicago Collaborative, another key player, has been managing community engagement and public outreach. Throughout 2016 and 2017, Smart Chicago hosted a series of neighborhood events to educate locals, address questions, and collect feedback as part of the AoT Civic Engagement Project. Smart Chicago, alongside AoT’s project leaders and the City of Chicago, also shared draft privacy and governance policies online for public feedback. These engagement efforts culminated in the August 2016 release of the final version of the project’s governance and privacy policies, as well as responses to public feedback and the Array of Things Civic Engagement Report.

Other partners include a collective of scientists from twelve universities worldwide, as well as technical advice and support from industry partners such as Microsoft, Cisco, and Motorola Solutions, among others. 


 A City of Chicago employee installs an AoT node on a light post at the intersection of Damen and Archer on the city’s southwest side, August 2016. Source: UrbanCCD.

Why is it significant?

If the fitness tracker has evolved people’s ability to manage personal fitness, then the concept of “a FitBit for the city” has the potential to considerably—and more broadly—evolve how urban data is understood and used by researchers, local government, and the general public.

Data collected from AoT sensors includes light, air and surface temperature, vibration, carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, barometric pressure, sound intensity, pedestrian and vehicle traffic, and surface temperature. With continued development, AoT may soon be able to collect data on flooding and standing water, precipitation, and wind. 

This node-level data will soon be available to anyone who is interested. With it, residents, researchers, urban planners, developers, government leaders, community groups, and any other interested party will be able to proactively monitor, understand, and engage with AoT data. 

So how does AoT’s data translate into action? For local government, data generated by the Array of Things’ sensors will help make both short-term operations and long-term planning more efficient. AoT will also be able to effectively realize cost savings by anticipating floods, traffic safety incidents, and other challenges. For example, Chicago’s current monitoring of its temperature data is based on just three sensors across the city. With temperature data becoming available at hyper-local levels, the city could vastly improve its understanding of micro-level weather patterns and, as a result, better estimate where to apply salt before snow storms. 

Non-city users, meanwhile, will be better able to take specific actions that will make Chicago healthier and more livable. Those actions could include the development of innovative applications, such as a mobile app that allows residents to track their exposure to certain air contaminants, or navigate the city while avoiding urban heat islands, poor air quality, or excessive congestion and noise. 

How are AoT’s planners including Chicago’s residents and communities in the project?

Smart Chicago Collaborative began its community engagement efforts in 2016, with meetings held on the city’s central and south sides. The organization has been managing all aspects of community outreach for AoT, including a transparent documentation process. Smart Chicago’s goals are to educate Chicagoans about the project, understand local concerns and expectations, and find opportunities for collaboration when possible.

In addition to SmartChicago’s community engagement programming, UrbanCCD has partnered with Chicago’s Lane Tech High School to offer “Lane of Things,” an eight-week course about computer science concepts such as programming, digital fabrication, and data science. Intended to foster resident understanding of AoT from an early age, students in the class devise sensor kits to gather data on school life, such as noise levels in hallways and humidity in gyms, and offer ideas and proposals on how to improve their local surroundings. The workshop, which debuted in 2016, is jointly taught by UrbanCCD and the School of the Art Institute of Chicago (SAIC), the latter of which helped with AoT node design. With 2018 around the corner, the Lane of Things initiative is now gearing up for its third year of operations.  

Lane of Things constitutes a first step for AoT’s youth education programming as well. “We plan to soon expand our high school programing to other schools throughout Chicago, too,” noted Catlett at an AoT community engagement meeting in October of this year. “This would include training teachers and workshop facilitators so that its curriculum could be offered to a larger number of students.” 


Douglas Pancoast, Associate Professor at the School of the Art Institute of Chicago and key AoT collaborator, works with a student involved in the Lane of Things initiative at Lane Tech College Prep High School, Chicago. Source: UrbanCCD.

What is the project’s impact outside of Chicago?

As AoT’s technology is fully replicable, other cities and universities have taken notice, and have been engaging with Catlett and UrbanCCD to potentially replicate the project. Representatives from cities across the United States and globally have come to Chicago to learn from Catlett about how to craft policies and procedures for implementing a system like AoT.

In the United States, Seattle is expected to be the first AoT-activated city outside of Chicago. Other cities in the United States engaged on the project include Denver, which will leverage a local partnership with Panasonic; Palo Alto, which will work with Stanford University; the City and University of Chapel Hill, NC; and Portland, OR.

Abroad, Mexico City, Amsterdam, and cities in the United Kingdom have also expressed interest, as have cities in China, India, and Southeast Asia; in total, UrbanCCD has fielded more than 100 inquiries from locations across the globe.   

What other information is out there about the Array of Things?

Since the concept for the project was first introduced to the public in 2014, AoT has been covered numerous times by local, national, and foreign press. 

The Ash Center’s Data-Smart City Solutions has covered the Array of Things from multiple angles, including its context within Chicago and around the world.   

In its look at sensor network initiatives, the Wall Street Journal was among the first national outlets to cover AoT. Bloomberg View also curiously prodded the implications of AoT upon the project’s debut to the public. When AoT officially went live two years later, USA Today chronicled Chicago’s hopes for success for the project. 

“Five years out, if we’re successful, this data and the applications and tools that will grow out of it will be embedded in the lives of residents, and the way the city builds new services and policies,” former Chicago CIO Brenna Berman told the newspaper. “It will be viewed as a utility — the same way we view our street lights and the way we view our buses. They are there for us and they help us get through the city more easily.... They are just part of our everyday life.”

CNN’s coverage, meanwhile, observed AoT’s potential as a solution for issues such as pollution-induced asthma, a public health issue in Chicago. On the city’s local front, both Chicago Magazine and the Chicago Tribune have covered AoT, with both providing in-depth dives on the project implications for city residents. The Tribune has covered AoT programming in local high schools as well.

Most recently, the BBC filmed a short feature on AoT’s workings as a tool against air pollution, which featured interviews with Berman, Catlett, and other key players in the project.

Where can information be found on AoT’s most recent updates?

In addition to coverage from Data-Smart Cities and its Twitter account @DataSmartCities, AoT has its own Twitter account - @arrayofthings - which includes the project’s current happenings in Chicago and around the world. For direct updates, follow the Array of Things website at    

Sean Thornton is a Program Advisor for the Civic Analytics Network at Harvard's Ash Center for Democratic Governance and Innovation, and writer for Ash Center publication Data-Smart City Solutions. Based in Chicago, Sean holds joint Masters’ degrees from the University of Chicago in Public Policy and Social Service Administration. His work has spanned the city's public, philanthropic, and nonprofit sectors.