That final aspect has made these sensors somewhat controversial, as residents fear that they could eventually be used to collect much, much more. While it's unlikely that this could compromise data any more than a coffee shop's Wi-Fi network could, it is possible that basic identifiers could allow law enforcement to track a single person's movements across a city — a potentially powerful ability when tied with Chicago's security cameras. A company in London actually tried this last year using trash cans, but it was ordered to stop just days after getting started. It's said that Chicago's sensors are being set to not collect this type of identifying information, however, which may allay these concerns.

The city of Chicago won't be the only party with access to all of this data, either. Rather than keeping it private, it'll reportedly all be published publicly, allowing people to use it for research or for developers to think up new uses for it. "By making this data public, we can imagine people writing all sorts of applications taking advantage of the data, including, hopefully, ones we never would have thought of," Charlie Catlett, director of the Urban Center for Computation and Data, tells WBEZ. There will reportedly be around 50 of these arrays of sensors installed by the end of the year, and within a few years, that number is expected to reach closer to 400.