Electrical engineers at the Massachusetts Institute of Technology have created a new kind of home security device that sees through walls to help people keep tabs on elderly relatives or small children.
MIT professor Dina Katabi demonstrated the device, called Emerald, at the White House in August. Now she plans to take a sabbatical in January in order to launch a new company to sell the device.
Since 2013, Katabi and her colleagues have been working on ways to use ordinary radio waves, like those emitted by wireless Internet routers, to track people inside buildings. These radio waves travel through walls and bounce off people and objects in an adjacent room.
Emerald transmits an extremely low-powered radio signal – Katabi said it’s 10,000 times weaker than the signal emitted by a cell phone. The device then picks up the reflected radio energy and uses complex algorithms to recognize reflections coming from human bodies. The system can distinguish between up to 15 different people in one room, with 90 percent accuracy. It’s capable of detecting specific body parts, such as arms and legs. It can even detect the tiny motions in a person’s body caused by his breathing and heartbeat.
“Our main interest is really elderly care,” Katabi said. An Emerald device could keep track of a person’s movements, and could instantly detect a person falling down. The device could then transmit a message to a family member or other caregiver via the Internet. “Today the only thing you have to detect falls is to ask your mom and dad to wear a pendant all the time,” said Katabi, and many people forget to wear their pendants or let the batteries go dead.
While the first Emerald device will be designed to monitor senior citizens, future versions could be used as baby monitors. Such a device could instantly alert parents if a child stopped breathing, without the need to attach a physical sensor to the child’s body.
An Emerald co-developer, doctoral student Fadel Adib, said the technology also could become popular with videogame developers and filmmakers. Today, these creative artists must use complex and expensive motion-capture systems to simulate the movement of digitally-generated characters. An Emerald system could track body movements just as accurately, but at much lower cost.
Katabi has been in contact with potential investors but hasn’t raised any funds yet. As for the price, “it will be in the same range as typical consumer devices like the Nest thermostat.” That would put the Emerald’s price tag at about $200.
A paper detailing the Emerald technology and written by Adib, professor Frédo Durand, doctoral student Chen-Yu Hau, and undergraduate intern Hongzi Mao will be presented at the SIGGRAPH Asia conference in Kobe, Japan next month.