Disclosed are systems comprising: a transmitter background; a receiver background; a plurality of transmitter units affixed on the transmitter background, each transmitting an encoded electromagnetic wave (EM), wherein the electromagnetic wave is transmitted as a wide beam; and a plurality of receiver units affixed on the receiver background, wherein each of the plurality of the transmitter units is in electromagnetic communication with at least one of the receiver units. Also disclosed are methods of identifying the presence of an object intersecting a spatial surface. Further, a housing for the system is disclosed.