When considering important features of a home, safety would likely be on everyone’s list. As a nurse living in Queens, New York, Marie Van Brittan Brown often came home after dark to an empty house. Her husband’s long hours away as an electronics technician and delays in police response time to emergency calls had Brown feeling unsafe in her neighborhood. This drove her to invent a security system to see who was knocking on her door.

Between Brown’s creativity and determination and her husband Albert’s knowledge of electronics, the couple designed their “home security system utilizing television surveillance.” They jointly received a patent in 1969, with Marie being listed as the principal inventor. The system created a closed-circuit television system for surveillance known as CCTV, which included peepholes, a television monitor, and two-way microphones. A New York Times article that published shortly after their patent was granted explained that the system would allow a resident to “scan and interview” someone at their door, and then either admit them or trigger an alarm.

The invention was foundational for the development of home security systems we are familiar with today, and was subsequently cited on dozens of patent applications. But it was cost-prohibitive for most homeowners at the time, and the Browns did not receive much financial compensation for their invention. Today, Marie Van Brittan Brown is not a household name, despite her technology being a household staple. But she served as an inspiration to her daughter, Norma, who grew up to be a nurse and an inventor.