WISP Needs No Battery Or Cable

One of the problems with the Internet of Things, or any embedded device, is how to get power. Batteries are better than ever and circuits are low power. But you still have to eventually replace or recharge a battery. Not everything can plug into a wall, and fuel cells need consumables.

University of Washington researchers are turning to a harvesting approach. Their open source WISP board has a sensor and a CPU that draws power from an RFID reader. To save power during communication, the device backscatters incoming radio waves, which means it doesn’t consume a lot of its own power during transmissions.

The big news is that TU Delft has contributed code to allow WISP to reprogram wirelessly. You can see a video about the innovation below. The source code is on GitHub. Previously, a WISP had to connect to a PC to receive a new software load.

Of course, RFID tags already grab power from RFID readers. However, a normal RFID tag doesn’t have any processing power or sensor inputs. The WISP has a 16-bit CPU. Development is currently on version five. There is also a version that can interface with the NFC readers common in modern smartphones and other devices.

There are also similar devices that attempt to harvest energy from ambient sources (radio and television broadcasts, for example). One big advantage to not having batteries is that the devices can be placed where they are inaccessible. For example, a building could have sensors poured into concrete that inspectors would power and read wirelessly. Obviously, being able to update such a device wirelessly would be a big benefit since you can’t retrieve the device to connect a cable (or a battery) to it.

Stealing power is not a new idea. We’ve looked at heat harvesting before, as well as a carbon monoxide sensor that steals heat from a hot water spigot. Then again, you can also use the power of the human body (no Matrix required).