When it comes to powering electronics projects, the choices can be pretty limited. Most makers will choose between plugging their project into a wall or running it off of a battery, making a choice between reliability and mobility. But in the Internet of Things, objects can’t afford to make that choice— devices must be both reliable and mobile. In embedded IoT projects, recharging batteries can be next to impossible. So, how will the next generation of embedded wireless devices be powered? In the same way they receive data: They’ll be powered wirelessly.
An RFID chip. Image courtesy of nx-id.
This kind of technology has been around for a while in the form of active RFID chips. The chips are both powered and read by an RFID reader when the two are close together. Historically, all these chips have been able to do is store and retrieve small amounts of data. However, researchers have been making advancements in expanding the functionality of these RFID systems to include extra inputs and outputs. So far, the research has yielded systems (dubbed Computa) that can think for themselves and relay information back to a central RFID hub.
The most popular of these systems is the WISP platform, which has open source hardware and firmware. On top of the benefit of being open source, the WISP developers have the financial backing of Intel, Disney, and Google. At first glance, the WISP looks like a standard microcontroller with one main exception:
A WISP development board. Image courtesy of Extreme Tech.
A giant antenna, mounted on one side of the board and used for both power and communication, is the defining feature on this board. The WISP is currently on its fifth major revision, and the newest features bring some exciting improvements, the most important of which is the RFID frequency. The newest revision operates on UHF RFID on a frequency between 300MHz and 3GHz. This higher frequency is normally used for large-scale inventory, as UHF RFID can have a range of up to 12 meters. In the context of the WISP, it allows communication to exist over a longer range and provides more power for the antenna.
This enables major advancements for small sensor networks. Many research papers offer the example of wiring bridges or roads with sensors to monitor infrastructure health. However, the most important facet of this update is what could be coming in the near future. If the new generation of WISP makes it on up to 3GHz, it could potentially work with a number of different protocols that function near the same frequency such as WiFi and Bluetooth. This will appeal to makers who don’t have the budget for a UHF RFID reader and would rather just use their existing wireless framework, as well as to companies that wish to distribute small IoT products to consumers.
An early version of the WISP. Photo courtesy of the University of Michigan.
Power usage has been a stigma for the IoT community since the beginning, and various platforms have tackled this problem by making integrated batteries or simply making the chips more efficient. However, the central problem has remained. Computational RFID has the potential to be adapted to work with WiFi and other such protocols, and can help the market improve small items that have no business being battery-powered, such as the Amazon Dash.
Wireless power is the next logical step for the IoT, and WISP may be the right board for the job. Hopefully, more and more small-scale devices migrate over to wireless power. There are plenty of small electronics that could benefit from wireless power such as wireless keyboards, wireless mice, and television remotes. The WISP could open up a door to a new generation of wireless devices and revolutionize the Internet of Things.