The antenna and distributed sensor tags stream low-rate thermocouple data from a heatshield. In hybrid sleep/wake mode, sensors run for more than five years. (Image: NASA)

Researchers at NASA Johnson Space Center have developed a wireless instrumentation system whose sensor tags can operate for years in a low-power hibernation state with instantaneous over-the-air passive RFID wakeup using only a small coin cell battery.

The sensor tags, which are embedded with a processor and memory bank for acquired data, are placed about the vehicle and stream data only when queried by a fixed-location RFID interrogator. Otherwise, the tags remain dormant to preserve battery life. In the hibernating configuration, the microcontroller is the only circuit drawing power in the wireless sensor tag, and it is operating in the lowest power mode possible.

With a form factor close to a deck of playing cards, the system interrogator has custom software to interface with and service a population of sensor tags at the required data rates. Each EPCglobal C1G2 sensor tag uses incident interrogator energy to charge its small integrated circuit (IC), which reads an internal memory bank, encodes identification data, and uses that information to modulate and backscatter a reply to the interrogator using reflected interrogator energy.

Two tag interfaces allow the attached processor to power the reading/writing of data to the tag memory and then allows the interrogator to power the reading of the tag memory data. When neither of the two interfaces are engaged, the RFID IC is completely powered down. Reading and writing tag memory consumes relatively little power compared to the power draw of active transmitter/receiver protocols like Bluetooth, Zigbee, and Wi-Fi.

Compared to passive sensing protocols, this wireless instrumentation system enables sampling of a larger population of tags without the computational burden associated with surface acoustic wave (SAW) sensing. RFID-Enabled Wireless Instrumentation technology allows the RFID interrogator to write data through the interface of a sensor tag memory bank using only interrogator power. With only minimal cost to the sensors power budget, the microcontroller unit can read that data out over the serial interface.

This architecture proves useful on long-duration missions and for early sensor tag integration into vehicles during assembly when the sensors may remain dormant years before being operated.

NASA is actively seeking licensees to commercialize this technology. Please contact NASA’s Licensing Concierge at This email address is being protected from spambots. You need JavaScript enabled to view it. or call at 202-358-7432 to initiate licensing discussions. For more information, visit here .