Battery-Free Wireless Sensor Technology
We’ve been hearing about the “Internet of things” for years, a network of smart devices and sensors that connect all of your appliances and toys and equipment that will allow you to access (or at least monitor) just about everything. One problem holding back this ubiquitous connectivity is that most sensors require some sort of power source. If the sensor is attached to something that is already powered (like a refrigerator), that’s not a problem; but if you’ve got hundreds of sensors in a remote location, you’d need batteries.
Engineers at the University of Washington have come up with a possible solution: ambient backscatter technology that uses existing TV and cellular transmissions to allow devices to communicate with each other. The team has built small, battery-free units that can harness and reflect TV signals to contact other devices using a sort of Morse Code made up of ones and zeroes.
“We can repurpose wireless signals that are already around us into both a source of power and a communication medium,” said lead researcher Shyam Gollakota, a UW assistant professor of computer science and engineering. “It’s hopefully going to have applications in a number of areas including wearable computing, smart homes and self-sustaining sensor networks.”
This is similar to passive RFID, except that the ambient backscatter technology hitchhikes on radio waves from other devices, rather than relying on a signal from a dedicated reader.