Residents in Harlem say they like the idea, though some wonder if the appearance of Sky Watch has anything to do with the two new luxury condos built on a nearby corner.
"There was crime around here before and they never had it. Now all these expensive buildings, it's true," said one area resident. "But actually it's good though, because then I used to see a lot of crowd here and sometimes I was scared to pass here, but guess what, that doesn't happen anymore. It's a kind of deterrence and it's good."
Police say the Harlem tower was placed there to combat a rise in murders.
Sky Watch has also been tested in Crown Heights in Brooklyn where it reduced crime. Police are hoping to have three more towers soon.