This New Sensor Can Work Underwater, No Need For Batteries

Researchers from MIT have successfully developed a new sensor, along with a communication system that can work underwater without batteries and hardly use any power. According to the researchers, this system could be used to build an underwater IoT (Internet of Things) for monitoring sea temperature and tracking marine life, while it doesn’t require any regular equipment or power swaps.

In the system, the research team uses a transmitter to send out sound waves underwater toward a sensor embedded with receivers. When the soundwave hits the sensor, it transmits a small amount of energy. After that, the sensor sends back an answer using that energy, or it doesn't, corresponding to 1 or 0.This allows the sensor to communicate any information using binary. The receiver decodes a 1 for a reflected wave and decodes a 0 for no reflected wave. This technology can work for multiple sensors at the same time.

Basically, the system relies on allowing piezoelectric resonators to absorb the wave and deform (a 0 bit), or retain the shape and then reflect (a 1 bit). It's dependent on the information contained in the sensor. You can integrate any type of sensor with piezoelectric material. The binary signals will be collected, then interpreted.

The inspiration for the system came from a nature documentary called “Blue Planet.” A researcher worked on this project, Fadel Adib, who is also an MIT Media Lab’s assistant professor, was watching “Blue Planet.” Then he wondered how little we know of the ocean, and we can’t use Wi-Fi or Bluetooth signals or put batteries underwater because that could raise issues with pollution. And that’s how the researchers came with the solution.

Next, MIT researchers want to prove that their system can work at larger distances and communicate with other sensors for simultaneous transmission. It might transmit low-resolution images and sound as well.