Security doors in the US are now installed with security cameras and sensors, and have been since the early 1990s, according to security researcher and engineer Mark Smith.
But they were never designed for use outside a home.
“The first thing I would say about security doors is that they are not for use in public,” Smith told BBC News.
The new security measures have come in response to a spate of high-profile shootings in recent years, including the fatal shooting of a Dallas police officer.
Smith said the idea behind the doors came to him during a visit to Austin, where he was working at the time.
He had a long-running project to redesign doors in his home city, which saw him designing an automated door that would open automatically when the doorbell rang.
“I was trying to come up with a better design for my home that I could get across to the neighbors without the need for the homeowner to look at the door and say ‘Oh, is that a doorbell?’ and have the door automatically open,” Smith said.
In the early 2000s, Smith and a group of other engineers built an automated system that could open doors remotely.
They then worked on the software that would run the system.
“The software is called Auto-Doors,” Smith explained.
That software would take a picture of the door frame and the door itself and then run the calculations to open the door, and it would take an algorithm to determine if it should open or not.
“It’s sort of like if a computer sees a door and thinks ‘This door is a door,’ it will open it automatically, and the user just has to type in ‘I want to open this door’.” Auto-Doours had a couple of key features: it would only open if the door had been hit by a car before, and would only unlock if the person in the room had a key, so it would be hard for the person outside the room to break into the room and gain access.
It was also a great way to test out security systems, he said.
“We’re not going to try to put an open door in the middle of a room,” Smith recalled.
There were a few issues with the doors, though.
The system had to monitor every movement of the person on the other side of the sensor, and only open the system if the sensor detected movement of an object or movement of a person that was within about 2 centimetres of the camera.
And the doors had to be activated by either the key on the door or the keypad, which meant the system had no way to lock them off automatically if they were knocked down.
But after some time working on the project, Smith said he came to the conclusion that a more robust system was needed.
“If you look at any security system in a real-world situation, they’re going to be using a combination of sensors and algorithms to detect whether something is in the area and then open the doors,” Smith, who now works as a security consultant in the San Francisco Bay Area, told BBC Trending.
So the company decided to develop a way to automate the opening and locking of the doors.
“Basically, we started by taking a series of sensors that are attached to a door frame, we put a program on that runs a bunch of logic calculations that make sure that the door will automatically open and lock when the system gets a sensor signal,” Smith added.
Auto Doors is currently used by companies like Uber, Airbnb and more than 70 companies worldwide.
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