Devices Running on WiFi Power

Mobile devices are now radically smaller and more powerful than those available in the last decade were. They are also able to tackle more technology-related tasks compared to their erstwhile brethren. However, as their capability grows, they need to consume more power. With the Internet-of-Things and wearable technologies gaining increasing recognition from users, the need to keep them ‘on’ all the time is raising the topic of the best methods to power them.

Imagine that you have multiple sensors embedded around your home, tracking temperature changes by the minute and governing your thermostat to help conserve energy. How nice it would be if all the sensors operated without batteries. For then, you could rest assured that they, in tandem with the thermostat, will be properly monitoring the energy consumption. With battery-operated sensors, you will need to check on the status of each sensor frequently to prevent the system going haywire.

Now, engineers have developed a new communication system that does not require batteries to operate it. Instead, it uses existing Wi-Fi infrastructure and radio frequency signals to provide Internet connectivity to devices. Very soon, your battery-less wristwatch or other wearable devices will be able to communicate directly with other gadgets for storing information about your daily activities on your online profiles.

Earlier research by a group of engineers at the University of Washington had shown that it is possible for low-power devices to run off wireless waves such as those belonging to radio and TV. Their most recent work has taken them a step further. Now these devices, apart from operating without batteries, can send their signals to laptops or smartphones, using only wireless waves to generate the required power.

According to Shyam Gollakota, an assistant professor at the University of Washington, this is an essential step for Internet of Things to really take off. Potentially billions of battery-free devices will need connectivity when embedded in everyday objects. The research can now provide WiFi connectivity to devices and they claim their process consumes several orders of magnitude less power than that typically required for WiFi connectivity.

A tag made by the researchers listens for WiFi signals that a local router exchanges with a laptop or a smartphone. An antenna on the tag selectively reflects or absorbs the signal to encode it. The activity produces tiny changes in the signal strength of the radio waves that other devices can detect and decode.

The method allows central devices such as laptops, tablets and smartphones the ability to communicate with other low-power devices and sensors. The central devices exchange data with sensors that lie within a range of about two meters and do so at the rate of one kilobit per second. For example, a pair of smart socks could relay information about your jog to the jogging app on your phone. Although there is a chance for the radio signals to be buried in noise, the system works because the devices know the specific pattern that they need to look for.

That allows low-power Internet of Things to communicate easily with a large swarm of devices around them because of the prevalence of WiFi.