What is the Array of Things?

What if a light pole told you to watch out for an icy patch of sidewalk ahead? What if an app told you the most populated route for a late-night walk to the El station by yourself? What if you could get weather and air quality information block-by-block, instead of city-by-city?

The Array of Things project, AoT, is an urban sensing network of programmable, modular nodes that is being installed around cities to collect real-time data on the cities’ environment, infrastructure, and activity for research and public use. AoT will essentially serve as a “fitness tracker” for the communities where nodes have been deployed, measuring factors that impact livability in cities such as climate, air quality, and noise.

What types of data are collected, what's made available, and how often is it refreshed?

Environmental Data

There is a wide range of environmental data points that are collected by the nodes. These observations are present in almost all nodes, and they are considered stable. The observations that are captured in this group include:

  • Temperature, ambient and inside the node
  • Humidity, ambient and inside the node
  • Barometric pressure
  • Ambient, ultraviolet and infrared light
  • Sound pressure
  • Vibration
  • Magnetic field

Air Quality Data

Air qu​ality data is concerned with measuring gas and particulate matter concentrations in the air. Some of the observations have been thoroughly calibrated and are mostly stable, while some others in this category are still under active development. The observations that are captured in this group include:

  • Carbon monoxide
  • Ozone
  • Sulfur dioxide
  • Nitrogen dioxide
  • Hydrogen sulfide
  • Total reducing gases
  • Total oxidizing gases
  • PM2.5
  • PM10

Image Processing

In add​ition to the sensors onboard the nodes, there are two cameras on each node. The cameras are used exclusively by software that runs on a special board within the node, the edge processor. The software use the image data to make aggregate and statistical computations: the raw images are never sent to any non-ephemeral storage and never leave the node. The information gathered by the cameras include:

  • Vehicle count
  • Pedestrian count
  • Flooding d​etection

The data held by the API is truncated after one week: each observation has only a 7 day shelf life. If you need data that reaches further back then please use our archival site: https://afb.plenar.io/.

It's also important to note that data is refreshed/ingested every 5 minutes. While observations are recorded typically in 30 second intervals we only flugh those in 5 minute chunks. As a result, we rate limit the API so that you can only perform 1,000 calls every 5 minutes.