Inspired by how long it would take the police to arrive in her neighborhood, Marie invented and, together with her husband Albert, devised the first form of a home security system.
The system included a device that enabled a homeowner to use a television set to view the person at the door and hear the caller's voice. The home security system allowed the monitor to be in a different room, and all of this was possible via a radio controlled wireless system. If the person viewing the images on the monitor did not feel safe they could press a button that would send an alarm to police or security.
Although the system was originally intended for domestic uses, many businesses began to adopt her system due to its effectiveness.
The system also used a voice component to enable Brown to speak to the person at the door. If the person had criminal intent and tried to enter the house forcefully, the police would be notified with the push of a button. For any expected visitor or welcomed person, the door would be unlocked via remote control. For this invention of a system, she received an award from the National Science Committee.
Brown was quoted in the New York Times saying, with her invention “a woman alone could set off an alarm immediately by pressing a button, or if the system were installed in a doctor’s office, it might prevent holdups by drug addicts.”
The invention was basically the first closed-circuit television security system and is predecessor to the modern home systems today. It led to the foundation for video monitoring, remote-controlled door locks, push-button alarm triggers, instant messaging to security providers and police, as well as two-way voice communication.
Brown's daughter followed in her mother's footsteps and became a nurse as well as creator of her own inventions.