Not long ago (roughly 11 years) a MIT article stated that technologists envisioned a future where, “seemingly invisible computers will be embedded everywhere, collecting data about the environment and making it useful to decision makers.” Today, the Internet of Things is the realized vision and battery-free RFID sensors are driving much of this reality. In 2016 alone, over 5 billion RFIDs were sold and the market size exceeded 16 billion dollars.

For those unfamiliar with battery-free RFID sensors, Phase IV Engineering pioneered the use of wireless RFID sensors. According to  Phase IV Engineering, “RFID (passive) sensors are unique in that they transmit sensor data with no battery.” The term, “passive” means a RFID tag does not have a power source and only transmits a signal upon receiving RF energy emitted from a reader in close proximity of the tag. While the reverse, an “active” RFID tag is powered by a battery and automatically broadcast its signal.

The benefits of having passive, no-battery RFID tag include:

  • The RFID can be placed into walls, carbon fiber panels, rubber, pavement since there is nothing to maintain.
  • Without a battery to take up space, the IoT sensor can be incredibly small.
  • Due to no maintenance requirements, the sensor can be contained within an object to operate within harsh conditions

Here’s a video providing an example of a passive RFID tag used to measure temperatures

One example of the significance of battery-free sensors is a breakthrough researchers at MIT and Brigham and Women’s Hospital have made recently. The research team  designed and demonstrated a small voltaic cell that is sustained by the acidic fluids in the stomach. The system can generate enough power to run small sensors or drug delivery devices that can reside in the gastrointestinal tract for extended periods of time. Read this ground-breaking story.

The downfall, at least currently, with battery-free sensors is that they are only reliable at short distances of tens of centimeters to a few meters. As a result, today’s systems for communicating with battery-free sensors are restricted by the limited range. This is OK for many uses including as labels and bardcode-like applications for pharmaceutical drugs, clothes, security badges and manufacturing parts. But in large factories, shipping yards and warehouses, local proximity is an extreme barrier.  Well – it was an extreme barrier.

Researches at MIT announced a system that leverages drones as relays for battery-free networks. With this new system, drones can identify missing objects and track inventory across large environments. Read the full story.

Here’s a great example of how drones can help identify a single car among thousands in a shipyard.

This is a massive space to watch as the rate of innovation continues to accelerate.

What applications could you imagine for battery-free RFID tags? Post your thoughts in the comments.

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