Technology Review has an article on Belkin's purchase of Zensi, a maker of sensors to track domestic energy and water usage (which would be a useful supplement to the data gathered by smart meters, allowing more fine grained understanding and tuning of household power consumption) - Home Sensor Startup Snapped Up.
If you knew how much electricity your plasma television used or how much water your dishwasher drank at different times of day, would you change your habits to conserve more and spend less on utilities? Researchers at the University of Washington, Duke University, and Georgia Tech believe that you might. Several years ago they invented sensors that could track the electricity consumption and water usage throughout an entire building via a single point on each system. In 2008, the researchers founded a company called Zensi to commercialize the technology, and last week, they sold that company to Belkin, an electronics hardware manufacturer.
A line of easy-to-install sensors for homes could be commercially available within the next year, says Shwetak Patel, professor of computer science and engineering at the University of Washington, and co-inventor of Zensi's sensors. Data from such sensors could lead to itemized utility bills--and customers who are more aware of the energy sinks in their homes, he says.
Right now it's impossible for a consumer to get an accurate gauge of energy use without deploying numerous expensive sensors. But cost reductions in key technologies have made the concept of watching every device in a home more feasible, says Ivo Steklac, executive vice president of sales and strategy at Tendril, a Boulder, CO-based, energy-monitoring startup. The key technologies are high-speed analog-to-digital conversion devices, digital signal processing algorithms, low-power communications, and ubiquitous Internet access and connectivity, Steklac says.
The concept behind Zensi's technology is simple: a single sensor is plugged into a wall outlet, where it "listens" to the high-frequency electrical noise produced in the wiring when different devices are turned on. Each electrical device has a signature that is unique to the kind of device it is, its brand, and its location within a house. This information, in turn, reveals its energy consumption. MIT professor Fred Schweppe, and others tested a similar idea more than a decade ago. In the case of plumbing, a sensor is connected to the hose spigot on the side of a house. When a toilet is flushed or a sink is turned on, the sensor detects the characteristic change in pressure.
Data from the electricity and water sensors is sent via the Internet to a base station for analysis. The algorithms differentiate between different devices and calculate electricity and water usage.