Data drives the future, and according to Dinesh Bharadia, an associate professor at UC San Diego, “data will be the next decade’s ‘silicon.’”
As the Internet of Things (IoT) continues to grow, data is easier than ever to gather.
Sensors and smart devices are now everywhere, connecting us to the cloud and making data sharing and analysis possible.
However, many of these sensors rely on batteries and struggle to capture changes in real time.
Now, things are changing. New research presented at the 22nd ACM Conference on Embedded Networked Sensor Systems (SenSys 2024) by Bharadia and lead author Nagarjun Bhat shows that real-time, battery-free sensing is not only possible but can also be affordable and efficient.
They discovered a way to repurpose Radio Frequency Identification (RFID) tags—common, low-cost tags used in inventory tracking—as sensors that don’t need batteries to operate.
Ph.D. student Nagarjun Bhat, working with Bharadia, focused on using RFID tags for passive sensing. These tags are usually inexpensive, costing only a few cents to a few dollars, and are already widely used by retailers and in libraries. An RFID tag typically works by sending data from a small chip to a reader, which then sends the information to a computer for interpretation.
Seeing the potential of these inexpensive tags, Bhat and Bharadia wondered if they could be modified for battery-free sensing. Traditionally, most sensing systems rely on analog-digital converters to collect and process data. However, these converters need a lot of power, often from a battery, limiting their practicality. Battery-powered systems can be bulky and costly, making them hard to use on a large scale.
Instead, Bhat and Bharadia’s approach skips the need for power-hungry converters. By directly sensing changes in the environment—such as shifts in temperature, humidity, or light—these modified RFID tags can send data to a reader without needing batteries. This could enable a wide range of applications without costly or bulky hardware.
Bhat and Bharadia’s battery-free RFID sensors enable immediate data collection, a major step up from previous technology that often only sent information when specifically requested. This innovation opens up new possibilities for practical applications in agriculture, sports, and beyond.
For instance, in agriculture, large irrigation systems often rely on just a few big sensors to cover entire fields. Although effective, this approach doesn’t allow for detailed data. RFID-based soil moisture sensors can be spread throughout a field, with each tag reporting moisture levels at its specific location. This enables farmers to manage water distribution with precision, conserving resources and improving crop health.
Similarly, RFID tags could be used to track athletic performance in real time. Today, many athletes need special facilities with expensive force plates to measure their jumping power or posture. By embedding RFID sensors into shoe soles, these tests could be done in any training environment, making data collection more convenient and affordable.
Another potential use is in parking garages, where RFID tags could monitor occupancy. Placing a light-sensitive RFID tag in each parking space allows the system to detect when a car is parked and instantly report which spots are occupied. This information can then be sent to a central system, helping drivers find available spots faster.
Bharadia and Bhat believe their innovation has the potential to transform data collection, especially with the growing demand for AI-powered insights. AI needs massive amounts of data to function effectively, and battery-free sensors make it possible to gather data that’s otherwise hard to reach. Bharadia noted, “AI is everywhere now, and it’s powered by data collected by sensors. Our battery-free sensors can unlock a lot of valuable information.”
Their breakthrough highlights an important direction for the future of IoT and AI. By transforming RFID tags into low-cost, battery-free sensors, Bharadia and Bhat have shown that data collection can be sustainable, scalable, and accessible.
This work, which they presented at SenSys 2024 in Hangzhou, China, points toward a world where real-time, battery-free sensing could help us understand our environment more deeply and make better decisions.
